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SPArKy_Dave

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  1. SPArKy_Dave

    Deciphering engine number

    It's from an 08/79 Fairlane - JG63WT 15B9 = block casting date code = 15/02/79
  2. Standard Definitions You probably know a lot of these terms already and some others ring a bell, but you may not be clear on their exact meaning. The following explanations are intended to be simple but useful. When you understand the concepts, you can start to apply them, then see how they relate to each other, and finally use that knowledge to improve your muscle car’s handling. Pickup Points Simply put, these are the pivoting points of the suspension. The pivot axis of each bushing, the center of the pivot ball in each ball joint, and the tie rod ends are all pickup points. Invisible lines connecting these points (and also the arcs they swing in) dictate the geometry of the suspension. This forms the foundation the rest of the suspension is built upon. Geometry determines much of the physics, and the physics determine how the car drives and handles. Later in this chapter, I discuss moving some of these pickup points to achieve some big performance gains. Inside every ball joint is a pivot ball. The ball-joint’s pivot or pickup point is at the center of that pivot ball. The pickup points for an A-arm are at the center of each pivot bushing and the one inside the ball joint. Here are the pickup points seen from the front, as the arm would be mounted on a car. The curvature of the arm has no effect on the geometry; it is determined solely by the pickup point locations. Camber This is the vertical angle of a tire in relation to the ground. Zero degrees means perpendicular to the ground, or straight up and down. One degree of positive camber means the top of the tire is leaning outward by 1 degree from vertical. One degree of negative camber means the top of the tire is leaning inward toward the centerline of the car by 1 degree. The two main aspects of camber are static and dynamic. Static refers to the settings when you align the front end. Dynamic camber changes when the suspension moves as a result of the suspension geometry and vehicle movement. Since tires tend to have the best adhesion when their tread is flat on the road (at lower speeds and slip angles) or at negative camber (at high speeds and extreme slip angles), properly setting and controlling camber is very important. For our purposes, positive camber (either static or dynamic) is generally not a good thing. You’ll see why in later chapters. One of the best tuning aids you can buy is a good, portable caster/camber gauge. This SPC Performance Fastrax unit has been a staple at race tracks for years, but is just as quick and easy to use at home. This one is fitted with optional adapters to make accurate toe measurements easier and faster. SPC makes these to fit everything from go-karts to monster trucks. (Photo Courtesy SPC Performance) Caster The tilt of the spindle, more correctly called the steering knuckle or upright, toward the front or rear of the car in relation to the ground is its caster angle. If the top of the spindle is tilted toward the front of the car, it’s called negative caster. If it’s tilted toward the rear of the car, it’s positive caster. Mild or negative caster settings tend to make manual steering cars easier to steer, but more positive caster provides better on-center feel, more steering feedback, and much better straight-line and high-speed stability. Guess which one you want to shoot for in your performance car? Note that since caster is measured in relation to the ground, changes in the car’s rake or ride height from front to rear alters the caster. Modern cars tend to run a lot of positive caster, with 7 degrees being common and some cars running as much as 12 degrees. Only specifically designed suspensions work well with such high numbers, but older cars can still benefit greatly from higher-than-stock positive caster settings. Roll Center (RC) This one is a little harder to explain because you can’t see it or easily demonstrate it. But it’s still very important. When any car corners, it grips the road with the tires at ground level, but the body and weight of the car are much higher off the road. There is a certain amount of lean (or roll) caused by centrifugal force. Think of the leaning car as an upside-down pendulum. The roll center is the pivot point of that pendulum. Every car has both a front and rear roll center and they are seldom the same height. In traditional front-engine cars with solid rear axles, the rear roll center is usually higher. A line drawn between these two points is referred to as the roll axis. Think of this as if the car’s body is put on a rotisserie and the roll axis is a shaft going through the car that it pivots on. Why do you care about this? Because the height of the roll centers and roll axis partially determine how much spring rate and roll rate the car requires to handle well. They also determine how body roll affects suspension loading. In many cars (and traditional muscle cars certainly fall into this category) the roll centers actually move around quite a bit while you drive. If you’re thinking that sounds like a bad thing, you are right! It means that the spring rate and roll rate requirements of the car can change dramatically mid turn. Since it’s rather difficult to swap out your springs or sway bars while your car is moving, you want to have the roll centers in a favorable location and keep them there if possible. Roll center movement is called migration, and it can move vertically and laterally. This diagram displays extreme negative camber. The top of the tire is angled inward toward the centerline of the vehicle. Here you see extreme positive camber; the top of the tire is angled out and away from the centerline of the car. This diagram shows zero camber. The tire is straight up and down. Zero caster is when the pivot axis of the spindle is straight up and down inside view. Positive caster is when the top of the spindle is tilted rearward toward the fire wall in side view. Positive caster is always desirable in performance suspensions. Negative caster promotes directional instability which makes it undesirable. This diagram shows the roll center (black dot). Notice that in dive and roll the RC has migrated about 6 inches laterally. You can also see the instant center (blue dot), which is at the convergence point of the upper and lower A-arms. When you’re talking to your car buddies about your suspension improvements, mention that you’ve minimized lateral roll center migration and you’ll instantly become the new local suspension guru. Just make sure you read the rest of the book before you say it because lots of questions are sure to follow. It’s generally difficult to alter roll center locations on a factory-built car, but advancements in aftermarket suspension parts have made it much easier, and I address how and why to change them later on. Note that some race car books have said that moving the roll centers to tune the suspension isn’t the best idea due to its complex repercussions on other aspects of the suspension geometry (such as the camber curves). That’s true in a way, as it is complex and it shouldn’t be toyed with casually. But, they’re assuming you have a very competent suspension design to start with and that it only needs fine tuning. Read on to see that it’s often very beneficial to change more than just the roll center on some muscle cars, so this can really work in your favor. Center of Gravity (CG) This is the top-to-bottom, side-to-side, and front-to-back balance point of the car. In other words, if you could hang the car from a chain at this single point, it would be perfectly balanced. That may not seem important, but this point determines the car’s front-to-rear weight bias and also affects how much the car rolls in the turns. The vertical distance between the CG and roll center (RC) forms a moment arm. In physics, a moment is loosely defined as torque caused by load applied some distance from a pivot point. In this case, it’s basically an invisible lever, like a pry bar that causes the car to roll in the turns. The upper end of the moment arm is pushed on by the mass of the vehicle and centrifugal force. Shortening this lever reduces its leverage and reduces body roll. This can be done by lowering the CG, raising the RC, or both. All else being equal, a lower CG is generally a good thing. Lowering the ride height of a car is the easiest way to do it. It can also be done by situating heavy components, such as the engine and transmission, lower into the chassis. Instant Center (IC) This is another one you can’t see, but it’s pretty easy to visualize. If you draw an imaginary line through the pickup points of two suspension arms, the instant center is the point where those lines converge. There can be a lot more to it, but that’s as complicated as we need to get for now. This is a handy piece of information for everything from helping to determine tie rod location (for minimizing bump steer) to making a car hook better at the drags. Roll Stiffness Plain and simple, roll stiffness is defined as the car’s resistance to body roll. It’s determined mainly by the rate of the springs and anti-roll bars (sway bars), and it plays a big part in determining how many degrees the car rolls on its roll axis when cornering. Here you see the rear instant center (or IC) of a 4-link rear suspension in side view. By moving the pickup points of the rear trailing arms the location of the IC can be moved to obtain the desired performance from the rear suspension. Spring Rate Spring rate is a measure of stiffness and is generally expressed in the number of pounds it takes to compress a given spring 1 inch. This measurement is then multiplied by the number of inches the spring is compressed. So, a 500-pound-per-inch (lb/in) spring requires 500 pounds to compress it 1 inch, 1,000 pounds to compress it 2 inches, 1,500 pounds to compress it 3 inches, and so on. Some springs have a progressive rate. It’s very common on multi-leaf springs, but some coil springs are of the progressive-rate type as well. If a coil spring has its coils spaced much closer together on one end when compared to the other, it’s a sure sign that its rate is progressive. For example, a progressive-rate spring may start out at 500 lbs/in, but the next inch of compression may increase the rate by 550 pounds, the next by 600 pounds, and so on. At 3 inches of compression, this spring’s rate would be 1,650 lbs/in. This is often touted as an advantage, but it has its pitfalls as well. (See Chapter 3 for more details.) Shock Rate Shock rate is a way to express the amount of dampening provided by a shock absorber. Shock rates aren’t as easy to express as spring rates because, like progressive-rate springs, shock dampening rates vary throughout their travel. Shocks also have different rates in jounce (compression) and rebound (extension). Additionally, these rates can vary with shock piston speed. As a result, accurate shock data is generally expressed in charted curves. Adjustable shocks have different curves for each setting or combination of settings. Tire Slip Angles Due to cornering forces and tire distortion under load, the actual direction that a car travels in and the direction the tires are pointed in are different during cornering. The difference between these directions is called the slip angle. Equal slip angles, front and rear, yields a neutral-steering car. Higher slip angles in the front cause understeer. Higher slip angles in the rear cause oversteer. This is a progressive-rate coil spring. They’re easy to identify due to the different spacing between the coils. Progressive-rate springs are generally reserved for certain specific applications. (Photo Courtesy Total Control Products) Understeer When a car exhibits understeer, the front end of the car demonstrates some resistance to turning. In other words, the car feels like it wants to go straight when you want it to turn. This is often referred to as push. Understeer is present in most factory cars because people seem to react to it naturally. If the car’s not turning enough they just turn the wheel some more. Understeer can be increased by dynamic positive camber gain and tire sidewall deformation. In general, more front spring rate or front sway bar rate increases understeer. Excessive understeer tends to make a car feel heavy and unresponsive. As lateral load is applied to a tire it starts to slip sideways. As long as the tire still maintains some grip it continues to function in the usual manner but it moves at an angle to its centerline. This is the tire’s slip angle. If the tire loses grip entirely, the slip angle no longer applies and the tire simply slides out of control. A car exhibiting understeer. The wheels are turned into the turn but the car isn’t responding to the degree that it should be. This is also called pushing. Most factory cars are tuned to understeer because it’s very intuitive to control. When the car doesn’t turn enough you simply turn the wheel some more—at least until you run out of adhesion. Oversteer The opposite of understeer, over-steer is when the back end of the car feels loose and wants to slide out. Sprint cars and the sport of drifting demonstrate extreme examples of oversteer. To a good driver, oversteer in a controlled drift can be a lot of fun, but it can be very disconcerting to average drivers because they’ll need to counter steer and turn the wheel left to go right and right to go left. More rear spring rate and/or more rear sway bar rate generally increase the tendency to oversteer. Oversteer can be influenced by your right foot as well. As you apply throttle to rear-wheel-drive cars, you can often induce throttle oversteer and use it to tweak the car’s balance mid turn. This diagram illustrates oversteer. In this condition the rear of the car is loose and sliding toward the outside of the turn. This is a natural condition in drifting competition but feels very unnatural to most untrained drivers because the steering wheel must be turned in the opposite direction of the turn to negotiate it properly. This is particularly easy on high-horsepower cars. Sometimes it’s too easy!You may set these cars up with a little understeer as a safety net. All the horse-power in the world is no fun if, every time you get on it just a little too hard, the car spins off the road backward. Neutral Steer When a car is neutral, it turns exactly where you point it; no more, no less. When a car has neutral steer characteristics it’s said to be balanced. It is easy to tune and easy to drive fast, so this is something you’re shooting for. No car is perfectly neutral all the time but, if it’s close, you can easily make up for the difference with driving technique. When tuning a car’s balance, always start with settings prone to understeer and work gradually toward neutral handling. The closer you get to oversteer, the less room you have for driver error. Take your time—tuning is fun! Bump Steer More people ask me about this steering term than any other. Bump steer is when the front spindles and tires turn in or out as the suspension moves up and down. When this occurs every time the car goes over a bump or the body leans in a turn, the vehicle steers itself without the driver’s permission. It can also induce understeer or (more rarely) oversteer. Bump steer tends to make cars wander or dart from side to side, which makes them much harder to drive fast and annoying to drive at slower speeds. Under hard braking, weight transfer causes both sides of the front suspension to be compressed at the same time and the bump steer is expressed as toe change, typically toe-out, which makes the car unstable under braking. Bump steer in general is almost always bad. Most muscle cars have a great deal of bump steer by modern standards. (See Chapter 7 for more on diagnosing and fixing bump steer.) Here’s a common occurrence on factory muscle cars. For optimal (minimal) bump steer, the tie rod ends should line up with the gray line drawn through the ball joints and inner A-arm mounting points. Even more importantly, the centerline of the tie rod (the orange line) needs to intersect the instant center. As you can see, it’s way off. The result is bump steer so severe you can see it with the naked eye. A simplified diagram showing the basics of what it takes to attain nearly zero bump steer. The vertical orientation of the tie-rod-end pickup points is extremely critical. Note: a line drawn through them should intersect the IC. The horizontal orientation is determined by lines drawn through the ball-joint pickup points and the inner A-arm mounting points. The tie-rod-end pickup points should fall on these lines. This diagram gets much more complicated when you account for non-parallel A-arm mounting points on some cars, and also anti-dive angles. These basics are the same with conventional (box-based) or rack-and-pinion steering systems. Modern alignment racks can chart bump steer if the tech is willing to take the time to do it. This chart shows the bump steer curve of Tad Banzuelo’s well-modified 1995 Impala SS. SLA suspension cars usually have some deviation toward the extremes of their travel, but you can see the center 3 inches of travel (1.5 inches of compression and 1.5 inches of rebound) are quite good for a production sedan. (Photo Courtesy Tad Banzuelo) It’s common to use bump steer kits like this on race cars to tune out vertical misalignments. These can be a quick remedy for some issues, particularly if the outer pickup points need to go downward. If they need to go up, these aren’t much help. (Photo Courtesy Chris Alston’s Chassisworks) Ackerman This is sometimes referred to as “Ackerman angle.” Named after Rudolf Ackermann and first used on horse-drawn wagons, this steering term refers to the difference in the angles of the front wheels in a turn. When turning, the inside wheels follow a smaller radius than the outer wheels, so it is often advantageous to have the inside wheels turn sharper to follow that smaller radius. In effect, this dynamically alters the toe of the front wheels. Ackerman can be a touchy subject. In road race cars, the high-speed turns and high tire slip angles can favor parallel or even reverse Ackerman. But since street cars operate at much lower average speeds, Ackerman is generally a desirable feature. Most solid front axle cars with the steering linkage in front of the axle have reverse Ackerman. Adding Ackerman to cars that have very little can improve low-speed responsiveness. Although some race car components allow Ackerman performance, it’s generally not easy to alter on production cars. Toe Toe refers to whether the front tires are parallel (zero toe), angled inward toward each other in the front (toe-in), or angled outward and away from each other in the front (toe-out). Toe-in typically adds directional stability, while toe-out can make a car wander or dart from side to side. In most driving conditions, that’s undesirable, so toe-in is most often used. Traditionally, it’s measured at the tire’s outer circumference, front and rear, and at the same height off the ground. This measurement is expressed in fractions of an inch, with 1/8 inch of toe-in being the most common. Newer computerized alignment racks usually express toe-in measurements as degrees. With a 26-inch-tall front tire, 1/8 inch of toe-in equals about .7 degree. tocross is a good exception to the toe-in rule. With its tight, low-speed turns, a little toe-out is generally a good thing to improve turn-in, and helps the car rotate around the cones. (Photo Courtesy RideTech) An example of toe-in. Generally a small amount of toe-in is preferred, but this much is excessive. An extreme example of toe-out. Driving down the road, the tires create drag that takes up some play in the steering components and cause some deflection in the suspension bushings, and this reduces the dynamic toe-in to less than the static measurement. Hard braking also changes the dynamic toe-in due to the same factors, but in most production cars bump steer has a much larger effect. Replacing factory suspension bushings with low-compliance performance bushings reduces the amount of deflection and allow running a bit less static toe-in. Steering Ratio This is a function of the internal gearing of the steering box and any changes caused by the linkage. To determine this ratio in traditional muscle cars, you need to take into account the internal ratio of the box, the length of the Pit- man arm (and idler arm), and the length of the steering arms from the lower ball-joint pickup point to the outer tie-rod-end pickup point. Some cars (like 1967 to 1969 Camaro/Firebird) have interchangeable different-length factory steering arms to alter the steering ratio and the Ackerman. The 1963 to 1982 Corvettes have two tie rod mounting holes in their steering arms to allow ratio and Acker-man adjustment. Others can benefit from aftermarket packages such as the Street Comp-AFX package for GM G-bodies with tall AFX aluminum spindles and redesigned steering arms. These correct the factory bump steer, quicken the steering ratio, and improve Ackerman. In a turn, the inner wheel follows a smaller radius than the outer wheel. To accomplish this, it must turn sharper to prevent tire scrub. Note: At high speeds, pure Ackerman is thrown off by the tire slip angles. One way to a faster steering ratio and better steering geometry is through the installation of a rack-and-pinion kit, like this TCP Mustang unit. There are many rack-and-pinion kits on the market. While some of them are just okay, a few are truly quite good. (Photo Courtesy Total Control Products) Steering ratio is not just a function of the internal gearing of the steering box but also the linkage. A longer Pitman arm makes the steering quicker. Longer steering arms make it slower. The fore/aft location of the steering pickup points also affects Ackerman.(Photo Courtesy Steve Johnston) Rack-and-pinion systems are subject to the same stipulations, with the exception of the Pitman and idler arms, of course. Note: When installing a rack-and-pinion into a car that didn’t originally have one, the difference in the length of the steering arms can have a major effect on the final ratio. A fast-ratio rack-and-pinion from a sports car with 4-inch-long steering arms, if installed in a car with 7-inch steering arms, doesn’t perform like fast-ratio units because the final steering ratio is quite slow. The steering wheel also has an effect on perceived steering ratio. Most muscle cars came with thin, large-diameter steering wheels that wouldn’t look out of place on a city transit bus. A modern sports car has a much smaller, thicker wheel. If the original wheel is about 17 inches in diameter, you have to move your hands roughly 13 inches to turn 90 degrees. Substituting a 13-inch-diameter wheel, you only have to move your hands 11 inches to turn the same 90 degrees. You still have to turn the wheel the same number of degrees to get the same result but, since your hands don’t have to move as much, it feels quicker. The smaller-diameter wheels also yield a slight improvement in steering feel on over-boosted older cars due to the reduction in leverage. At the same time, it makes manual-steering cars much harder to steer at slow speeds. Front Suspension Relationships Each of the terms above (and many more) form relationships that define how the car handles. Most of the cars you’re dealing with in the muscle-car world have deeply flawed suspension designs by today’s standards. After you understand the relationships between components, geometry, and where the problems lie, then you can fix them and make huge improvements fairly easily. I focus here on the short/long arm (SLA) suspension, which is common in most muscle cars. Picture SLA suspensions as seen from the front of the car. SLA systems use a long pair of A-arms on the bottom and a much shorter set on the top. This allows more room for the engine and exhaust and gives it an elliptical camber curve. That can be a big benefit on a street car because the camber change starts out small, which minimizes tire wear, but becomes more aggressive the farther the suspension moves. In a traditional American muscle car, the lower A-arms usually consist of either a one-piece steel stamping actually shaped something like a capital letter A (as seen on Camaros or Chevelles) or a stamped steel U-channel arm, perpendicular to the car’s centerline, with a separate strut rod forming the other side of the A (like those on a Road Runner or early Mustang). These arms are roughly level with the ground, but with a slight slant downward toward the lower ball joint. The upper arms are usually stamped steel in a true letter “A” pattern. In contrast to modern cars, most of these angle downward toward the upper ball joints. Here lies the start of your problems. As each arm pivots on the bushings mounting it to the frame, the ball joints at the end of each arm swing in arcs prescribed by the length of each arm. With all four arms in the described orientation, the lower ball joints move outward just slightly when the suspension is compressed (also called bump or jounce). The upper ball joints move outward much farther because the arms are at a much lower angle in their arcs. The shorter arms also have more rapid gain due to their shorter length. Because the upright (often called the spindle) is attached to the upper and lower ball joints, it tilts out at the top and causes positive camber gain. An inside look at the rack (the long bar with the teeth) and the pinion gear. (Photo Courtesy Total Control Products) These billet-aluminum ATS pieces are a good example of aftermarket steering arms used to gain some advantages. I designed these to work with the ATS tall spindle package for the GM G-body. They have a unique vertical offset to correct almost all the factory bump steer and have been shortened to correct the factory Ackerman error, quicken the steering, and improve tie rod end-to-wheel rim clearance. These small changes make a dramatic difference in drivability and turn-in. (Photo Courtesy American Touring Specialties) There are some awesome steering wheels on the market today, but you don’t have to spend a fortune on one. I bought this old 13-inch-diameter Grant “Challenger” wheel at a junk-yard for $5 about 25 years ago. It’s been in my hands when I’ve done some of the stupidest things I’ve ever done in a car . . . and we’re both still here. I wouldn’t sell it for $1,000. This fat, leather-wrapped steering wheel and supportive seats don’t make your muscle car handle better, but they can make a huge difference in how well you handle your muscle car! A fast ratio 670 box is a great option. This Chassisworks unit has a slick, billet top cover. Other notable units are available from LEE, DSE, ATS, and others. Many refer to them as simply “600” boxes. There are many steering boxes in the 600 series, including the underwhelming 605 box, which is best used as a door stop. The 600-series boxes are not interchangeable, but most reputable companies marketing them as “600s” are selling the desirable 670 series. (Photo Courtesy Chris Alston’s Chassisworks) There’s still a place for the long-suffering 800-series Saginaw-sourced steering box on high-end cars. They can be tuned to be a good, fast-ratio box, but the 670s are even better. There are some applications where you don’t want a fast ratio box. This Unlimited Class open-course road-race car is running a special Lee Manufacturing 800-series box we custom ordered in an extra-slow ratio and with specialized valving to make the car more controllable at absurdly fast road speeds. (Photo Courtesy Chris Alston’s Chassisworks) This GM A-body suspension is typical of most SLA (short/long arm) suspension designs with true A-shaped upper and lower A-arms. (Photo Courtesy Gary Forman) If the car enters a corner at zero static camber and rolls a few degrees, compressing the suspension on the outboard side of the car, then that tire gains positive camber. Why is that bad? In this situation, the tire contact patch is being lifted off the road and being unevenly loaded. That means much less traction. The angles of the A-arms also dictate the instant center (IC) and RC. To determine the IC, draw a line through the pivot points of the upper and lower A-arms, as viewed from the front. Next, draw a line from the center of the tire’s contact patch on the ground to the instant center, and you’ve got your roll center. If the lower A-arms are either level with the ground or angled down toward the ball joints, and the upper A-arms are angled down toward their ball joints, then the roll center is below the ground. If all four arms are parallel, the roll center is at ground level. If the upper arms angle upward toward the ball joints, the roll center is above the ground. (Remember, when I discuss these A-arm angles, I’m talking about lines drawn through the pickup points, not the shape of the arms themselves.) This brings us back to the relationship between the roll center, the center of gravity, and the invisible moment arm in between them. For example, take two cars identical in every way except that one has a roll center below the ground and the other has its RC well above the ground. Due to its longer moment arm, the one with the lower roll center exhibits more dynamic body roll. This is due to its longer moment arm and its additional leverage on the mass of the car. More body roll means the more heavily loaded suspension on the outside of the curve compresses more, and therefore experiences more camber gain. Since, as you’ve seen above, cars with the upper A-arms drooping downward from the frame mounts also usually exhibit positive camber gain, you also get the tires rolling over toward the outer sidewalls and compromising traction. This makes for a one-two punch that pretty much knocks out any chance of good cornering performance. This type of geometry was very common in the 1960s, and some vehicles built on older platforms continued to use it even into the new millennium. The two-wheel-drive GM S10/S15 pickup is a good example. You won’t find this type of geometry on cars (or even trucks) of modern design, though. That’s why muscle-car enthusiasts are sometimes surprised that their new SUV drives and handles better than their high-horsepower, vintage performance car. Bump Steer Bump steer. Just a few years ago this term was seldom heard outside of racing circles. That’s remarkable when you consider the dramatic impact it has on how well or how poorly a car drives. Bump steer means that the spindles are steering to the left and right as the suspension goes up and down. This occurs due to misalignments in the steering and suspension pickup points. When it occurs on both sides at the same time it’s often expressed simply as toe change. Bump steer takes control of the car away from the driver, making the job of driving more difficult. The car is quite literally steering itself. Modern cars as a rule have very little bump steer. Traditional muscle cars, on the other hand, tend to have a lot of it. It’s no wonder that between the poor suspension geometry and bump steer, the vast majority of these cars have been relegated to low-speed cruising and straight-line drag racing. With a good understanding of what causes bump steer, and a little help from technology and the aftermarket, you can reduce it considerably, or even eliminate it. That yields a huge improvement in drivability and control for these older cars. There’s an old street rodder rule of thumb that says if you want to have zero bump steer (a very optimistic term) you simply have the tie rods level with the ground at ride height. Like many rules of thumb it’s technically not true, but it does have a grain of truth in it. Bump steer revolves primarily around tie-rod-end location and the pickup points within them. This is true with both conventional steering-box and linkage systems and also with rack-and-pinion systems. These tie-rod-end pickup points dictate the arcs that the tie rods swing in. If those arcs don’t match the arcs, the spindle and steering arms swing in the spindles will have to steer to compensate for the difference. A horizontal mismatch in tie rod length causes the arc it swings in to have the wrong curvature, which causes some deviation (bump steer), especially toward the ends of the curves. A vertical misalignment causes the angle of the arcs to change, which causes them to intersect rather than overlap. This causes very rapid divergence between the curves—in other words, really serious bump steer right from ride height. For this reason, 1/8 inch of vertical misalignment can have as dramatic an impact on bump steer as a couple inches of horizontal misalignment. Let’s consider that many classic muscle cars have 5/8 inch or more of vertical misalignment and you can see how serious the problem is. Right about now you’re probably asking, “Okay, bump steer is bad but how the heck can I tell if I have it?” Well for starters, if you have any kind of older muscle car you’ve got it, and probably plenty of it. I get calls all the time from guys who say that they’ve had this 1967 GTO or 1969 Mustang or whatever for 30 years and it’s never had any bump steer. Those guys are swimming in a river in Egypt . . . in denial. Unless Detroit or Dearborn made that particular car different from all the others (they didn’t) it’s an inherent part of the suspension and steering design. Some folks have just gotten used to it and don’t think it’s a big deal. That is until they get rid of it, then they always kick themselves for not doing something about it sooner. Remember the AM radio analogy from the introduction? If you’ve only every listened to an AM radio with one speaker you’d think it was pretty great but once you hear a modern stereo system it’s obvious how much the old AM left to be desired and it’s almost painful to go back. Traditional Ford suspensions have some obvious differences, but if you disregard the different shock and spring mounting, there’s still an upper A-arm. There is a lower A-arm as well—made up of two components: the arm and the strut rod. Together they form a single A-arm and complete the SLA suspension system. (Photo Courtesy Total Control Products) Mopar suspensions share some basic design traits with Ford suspensions, such as the use of strut rods. GM B-bodies and early (pre-1968) Chevy II bodies use a similar format as well. Mopars are unique with their use of torsion bars instead of coil springs, but they’re still a basic SLA suspension. (Photo Courtesy Ray Campbell) Whether your front suspension design is SLA or strut, as long as you have four wheels and suspension at each corner of the car, the same general dynamics always apply. Of course all bets are off with something like this 1936 reproduction Dymaxion (built by my dad, Chuck Savitske, for the Lane Motor Museum). With three wheels, rear-wheel steering, and two separate suspension and chassis (each with their own unique characteristics), the suspension dynamics are simply mind warping. When completed, it will look a bit like a road-going Zeppelin. You don’t need a million-dollar alignment rack to check bump steer. This simple method employing two wheel plates, two levels, and two tape measures is being used by RideTech to fine tune the bump steer on their Velocity Camaro. (Photo Courtesy RideTech) To accomplish the bump steer check, simply zero both levels. Measure the toe by subtracting the measurement of one tape measure from the other. Next, jack the suspension up 1 inch vertically, and measure again. Chart the results, and you’ll have the bump steer curve. Here you can see the bump-steer-adjustable Heim joint tie rod ends. Velocity already runs geometry-correcting tall spindles with relocated steering-arm mounting holes but, due to car-to-car variations and alignment differences, bump steer can usually be honed to an even finer edge. It’s not necessary on most cars; but, for the hardcore, there’s always a small edge to gain somewhere. (Photo Courtesy RideTech) Similar bump-steer-adjustable Heim-equipped tie rod ends were used to fine tune the bump steer of this 1969 Mustang. (Photo Courtesy RideTech) A very slick way of adjusting bump steer is Howe Racing’s QuickBump tie rod ends. These modular, greaseable tie rod ends use a 5/8-inch threaded stud that’s broached on the top for use with a hex wrench. You simply drill out the steering arm and tap it for 5/8-inch fine threads, and screw the studs in. And then, to make your bump adjustments, simply screw it up or down with a hex wrench. No disassembly required. Find your setting and then lock it down with the jam nut (not visible in this picture). This system gives you a high-clearance, greaseable and rebuildable, all-weather, bump steer adjustment system that easily outlasts the very best Heim joints. The ability to make very fine adjustments is also nice. At 60 mph, tiny variations in bump steer are likely unnoticed. At the 200+ mph speeds Steve Johnston’s Camaro is capable of, they may be very obvious! (Photo Courtesy Steve Johnston) The venerable “Guldstrand mod,” with its widely varying modification specs, is an invention of SCCA Trans Am racing. The original intent was to improve front suspension geometry without making any apparent changes to the car. It moves the upper pickup points of the upper A-arms by lowering the cross shaft mounting holes. They were often moved toward the rear of the car to allow for more static positive caster in the alignment. The more the holes are moved away from the stock location, the more grinding needs to be done for upper A-arm clearance. Some versions use more change for the front hole than the rear to reduce anti-dive, which is arguably excessive in first-generation GM F-bodies. Dropping these points also moves the upper A-arms closer to the subframe, and reduces droop travel. After receiving the Guldstrand mod, it’s important to check ball-joint travel on lowered cars using stock upper A-arms to be sure you don’t bind up the ball joints in suspension compression. A more sophisticated evolution of the Guldstrand mod can be seen in this Detroit Speed coil-over conversion. The fixture is used to precisely locate completely new upper A-arm mounts with integrated coil-over mounts. These mounts feature revised A-arm mounting locations, much like the Guldstrand mod, for improved geometry. (Photo Courtesy Detroit Speed and Engineering) If you’d like to verify that you have bump steer issues on your car before you throw time and money at it, just measure your toe-in at ride height, then jack the car up until the tires just about come off the ground and measure it again. The difference in the two measurements is about one half of your total bump steer. On most muscle cars that half is 5/8 inch or more of toe change. On many older cars you don’t even have to measure it; you can literally see the toe change from 10 feet away. Okay, so I’ve established that virtually all of the cars discussed in this book have some bump steer issues. What do you need to do to cure it? If you’re lucky, some aftermarket company that supports your car has already done the research and development for you and offers some kind of correction kit. These can take the form of spindles with relocated steering arms mounting holes, specially designed replacement steering arms, different-height tie rod ends, Heim-joint-style ends with height adjustment spacers, offset rack-and-pinion mounting bushings, or even different-height lower ball joints that relocate the spindles vertically and bring the steering arms and tie rod ends along with them. There’s no single “magic bullet solution.” The solutions vary from car to car and I cover them in more detail in Chapters 8, 9, and 10. As always, caveat emptor, let the buyer beware! Many companies tell you their parts or systems correct bump steer, or that they have “zero bump steer,” even if they do nothing to improve it—sometimes it even causes more bump steer. That’s why it’s important that you know what you’re looking at and what you’re really spending your hard-earned money on. There are two things to look for in tie rod location—the length and the height of each end, which also dictates its angle. In its most simple form, picture the suspension from the front with pickup points in the center of each ball joint and each A-arm’s bushings where they mount to the frame. Draw lines connecting these points horizontally to find the instant center as discussed previously. Remember that no matter what height the tie rod is at, a similar horizontal line drawn through the pivot points in the tie rod ends must intersect with the instant center. That gives you your angle. Now picture a vertical line through the inner pickup points where the A-arms mount to the frame, and another vertical line through the outer ball joint pickup points. The inner tie rod ends should fall somewhere on the inner line and the outer ones should fall somewhere on the outer lines. If one is offset 1-inch inboard the other should be as well and so on. That’s pretty much it. No, really. At least it’s as good as you need to get for general illustration. This basic model works on any SLA front end with arms mounted parallel to the centerline of the car. Some adjustment needs to be made for cars angled in plan view (as seen from above), and for those with a great deal of anti-dive, but this simplified model gets you in the rough ball park. For cars that do have arms angled in plan view or a lot of anti-dive you can rough in those adjustments fairly easily too if you have one very high-tech tool: a yardstick. Say you’re checking a GM A-body with lower A-arm mounting points that angle inward toward the front of the car in plan view. Get under the car and lay a yardstick along the axis of the lower A-arm bushings. Now notice that the inner tie rod ends sit about 5 inches forward of the lower A-arms. Where the yardstick intersects that line is roughly where your vertical line between inner pickup points should end. Likewise, if the car has a lot of anti-dive (the upper A-arms are angled upward at the front in side view) you can lay a straightedge on top of the cross shaft to extend this line fore or aft over the steering linkage to fine tune your vertical pickup points. Steering misalignment has predictable results. If the outer tie rod ends are too low or the inner ones too high, the front wheels will toe out when the suspension is in compression. This means when the front end dives under heavy braking, you lose toe-in and sacrifice straight line stability. Certainly a less-than-ideal circumstance. Conversely, the wheels toe in when the suspension is in droop. Scrubbing off speed under acceleration is also less than ideal. In a drag car that carries the front wheels off the line, the right front wheel generally touches down first. If it’s toed in, the car steers to the left. You don’t want that either. If the outer tie rod ends are too high or the inner ones too low the car will be unstable under heavy acceleration when the wheels toe out and will jerk to the right after a hard launch. As you can see, be it a street car, road race car, or drag car, bump steer has ill effects on all of them. You can also troubleshoot bump steer by simply checking toe change at different heights. If you use vertically adjustable tie rod ends or similar components to correct bump steer issues you can use these measurements to rough in their adjustments. You’re shooting for as little toe change over the full range of travel as possible. With this method you need nothing more complicated than a tape measure. Of course, it won’t be as accurate as a true bump steer gauge but it’s easy and free. If you become afflicted with severe “Bump Steer Correction Disorder” (BCD) and decide to buy a professional bump steer gauge, I suggest the Long-acre style with a single-dial indicator. They are much quicker and easier to use than dual-indicator gauges and usually less expensive as well. My last word on the subject of bump steer gauges (because I think we’re getting a bit beyond the scope of this book) is to make certain that it is absolutely, positively rock solid before you start taking readings. The very smallest amount of movement at the base of the gauge will throw all of your readings way off and drive you nuts. That said, for the vast majority of muscle car owners, buying a bump steer gauge will only result in a) eventually hurling it across the garage, or b) endlessly obsessing over bump steer minutia. So if you can locate a well-designed bump steer correction package for your car, go for it. Don’t say I didn’t warn you. SLA vs. Strut When I first sat down to write this book I have to admit that I didn’t give much thought to MacPherson-strut-equipped cars. I had always planned to cover the G-body GMs from the late 1970s and 1980s since their suspension basically trickled down from the early A-bodies, but an IROC or Mustang GT still doesn’t seem like a vintage muscle car to me. I suppose that’s because I remember when those models were introduced and how thoroughly new and modern they seemed at the time. Of course some of them are nearly 30 years old, and they are certainly muscle cars, so they do have a place here.(I’ll touch on the differences in their strut front suspensions versus a short/long arm suspension and then go into a lot more detail in Chapters 8, 9, and 10.) There are some fundamental differences between these cars and their older counterparts. One of these differences is a switch to the MacPherson strut instead of keeping the more familiar (at the time) short/long arms, or SLA, suspension. In a MacPherson front end, the upper A-arms are replaced by what is essentially a coil-over shock that has been designed specifically to tolerate side-loading forces. These are used to locate the top of the spindles laterally. This format is simple, light, and often less expensive to produce than an SLA front end so it has become the standard in most modern production cars. It looks like a strut, but it’s not a strut. Struts are used in lieu of upper A-arms, and this car has upper A-arms. The 1993 to 2002 GM F-bodies went back to SLA suspension. Note the tall, Studebaker-esque spindles and tiny upper A-arms. What looks like a strut is in fact a coil-over shock. The factory DeCarbon coil-overs are non-adjustable, while the one in the photo is sporting Spohn Performance A-arms and QA1 coil-overs. (Photo Courtesy Spohn Performance) Fords have a similar geometry modification, often referred to as the Shelby mod. The holes directly above the cross shaft mounting bolts are the originals. Drilling jigs are available from Total Control Products for 1964 to 1966 and 1967 to 1973 Mustangs and other Ford vehicles. (Photo Courtesy Total Control Products) Here’s the DSE package installed. It’s more work than the Guldstrand mod, but makes for a very beefy and clean installation with the added bonus of integrated coil-over mounts. (Photo Courtesy Detroit Speed and Engineering) The outboard pickup points in an SLA suspension are the ball joints, so using ball joints of a different height can directly influence geometry. Note the different heights and configurations of these ball joints, all for the same model of car. These can be powerful tools when used as part of a complete suspension package. Raising the upper ball-joint pickup point with a taller-than-stock spindle, taller ball joints, or even lowering springs, can result in a gain in positive static camber. This is an alignment issue, not a geometric one. Without aftermarket arms designed to work with this type of revised geometry, it can be difficult or impossible to attain a good performance suspension alignment with negative static camber. This lack of adjustment range can influence and compromise caster settings as well. Determining the geometry of a strut suspension is similar to determining that of an SLA suspension with a few variations. Rather than using upper A-arm pickup points, you draw a line perpendicular (90 degrees) to the center axis of the strut to help define the instant center. Horizontal lines are still drawn through the lower A-arms pickup points and from the center of the tire contact patch to the instant center to determine roll center location. This format, combined with the packaging constraints of the tall struts and their large strut towers, can impose some limits on the range of geometry a strut suspension can achieve, but it’s also hard to design a strut suspension with poor geometry. They tend to have very efficient spring-motion ratios, which means lighter spring rates than SLA cars, so don’t try to compare the rates to each other. The newest generation of strut suspensions sometimes use two lower ball joints, which form a virtual pivot point that allows for more dynamic camber gain when the wheels are turned, but that’s well beyond the scope of this book. It should be noted that 1993 to 2002 F-bodies, Camaros/Firebirds, are not strut-equipped cars. They use very small upper A-arms and large lower A-arms (think Tyrannosaurus Rex) and a long, non-adjustable coil-over shock that is often mistaken for a strut. Lastly, MacPherson strut suspensions don’t leave much latitude for geometry modification so it’s a good thing that they’re generally pretty decent to begin with. Rather than tweak their geometry you usually just tune a strut front end with the alignment settings, spring rates, and dampening. SLA Suspension Fixes Now that you know a little about the problems, you’re probably wondering what you can do about them. Well, you can ignore them and hope they go away, or you can move the pickup points that define the geometry and you can fix it. There are a number of ways to do this. If you were building a chassis from scratch, you could simply move the mounting points of the upper and/or lower A-arms to alter the geometry to your liking. That’s easier said than done when working with a production car, though. This is especially true when working with an original SS 396 Chevelle or K-code Mustang or any other rare car where you’d rather not ruin its potential collector appeal or value. There are a couple of modifications that can be done to the frame side-mounting points that don’t require major surgery. One is the Guldstrand mod (or G mod), named after racing leg-end Dick Guldstrand, for 1967 to 1969 Camaros and Firebirds. Another is the so-called Shelby mod for 1964 to 1965 Mustangs. (I address each of them in Chapters 8, 9, and 10.) Generally speaking, modifications of the frame side-mounting points require extensive cutting, welding, and fabrication beyond the scope of most hobbyists and even most professional garages. This leaves you with the option of modifying the outboard side of the suspension. These components are all bolt-on pieces that can easily be changed back to stock in case some poor, misguided individual ever wants to put the car back to 100-percent original and make it drive poorly again. The most common parts to get changed are the A-arms. That’s because they look cool and advertising implies that they’ll improve the geometry. This is only true to a very small extent. A-arms only connect pickup points; they don’t define them. They’re only capable of making changes in static alignment, which is important, but it’s not the kind of drastic geometry change you’re looking for. (See Chapter 2 for more information on aftermarket arms.) Upper and Lower Ball Joints These are the two outer pickup points that affect the camber curves, roll center location, etc. If you’re dealing with a car on which the lower A-arms are more or less in the proper orientation, but the upper ones are drooping down to meet a pair of short spindles, then it’s easy to see how a taller set of spindles might be a big improvement. A taller spindle moves the pivot point of the upper ball joint higher in relation to the frame mounting points, changing its angle and offering potential geometry gains. The same is true of taller ball joints. Although circle track racers have been using variations of this trick for years, SC&C was the first to use it to reengineer the front ends of muscle cars with purpose-built components. In the past, the degree of improvement has been severely limited by the selection of factory ball joints that would both bolt into the application and give some kind of gain. But, with the introduction of CNC-machined modular ball joints (from Howe Racing, mainly) offered with interchangeable studs of different heights, much more profound changes are possible. Caution should be exercised with these because it’s possible to create as many (or more) problems as you solve with them due to the thousands of possible combinations. Properly integrated into a complete package (such as the Street Comp packages I have developed and offer for sale through my company), they can yield serious geometry gains. Why does it have to be a package? Why can’t you just slap a pair of tall spindles or some tall ball joints on the car and go? Because any real change in geometry requires some other changes to go along with it. As the upper ball-joint pickup points are raised by taller spindles or ball joints, the upper A-arms have to swing upward and outward in their arcs. If the car is lowered (with springs or coil-overs) they swing up and out even farther. This adds positive camber, which has a negative effect on handling. Since the stock upper A-arms were designed with poor alignment specs in the first place, there’s no chance of putting in enough alignment shims to fix the problem. Also problematic because the shape of the stock arms is also intended to mount the ball joints at the proper angle to maximize suspension travel, a lowered ride height and taller spindles (or ball joints) can put the upper ball joints near the limit of their travel, even while resting at ride height. When the suspension is compressed, it can over-travel or bind the ball joints, putting extreme stress on them and the upper A-arms. This can lead to component failure and having a very bad day. Nobody wants this, so don’t try to cut corners. Do it right and do it once. Spindles Also known as steering knuckles or uprights, spindles are the next most common parts to replace. These fall into three basic categories: stock (or stock reproduction), dropped spindles, and tall dropped spindles. Stock or stock reproduction spindles are self explanatory. They’re the baseline from which the other types evolved. Simple dropped spindles share the same overall height as the stock spindles, but have the actual spindle pin raised (usually 2 inches) in order to lower the car. They’re usually installed just for looks and their claim to fame is that they drop the car but don’t change the factory suspension geometry. Well, considering that most muscle cars could benefit from some thoughtful geometry changes, I wouldn’t consider that a selling point. It’s also technically not true. They do alter the geometry, and can even provide a few benefits, albeit small ones. The lower ride height lowers the CG a bit. The new stance raises the RC on some cars just a fraction of an inch, shortening the front moment arm only slightly. The difference is so small, though, that it’s only academic. The camber curves are unaltered and lateral RC migration can either go up or down, depending on the car. There are also some downsides, though. Lowering a car without increasing the spring or shock dampening rates is often a recipe for the headers or other low-hanging components to bottom out on the road. For example, it may take the stock springs and shocks 3 inches of travel to absorb a bump and keep your exhaust headers 1 inch off the road surface. Drop the car 2 inches with no other changes and things may get ugly when it tries to move that same 3 inches! Also, most of the cars in this book see more geometry improvement from a set of performance rate-lowering springs that further reduce body roll. If you combine a rate-lowering spring with a 2-inch dropped spindle, you may end up with a ride height that’s too low and you’re bottoming out again. Raising the spindle pins has another consequence as well. Moving the pin up moves the wheel and tire with it, and puts the wheel rim much closer to the outer tire rod ends. This can limit the amount of wheel back spacing you can run and ultimately limit the front tire width. It’s important to take things like this into consideration so you don’t end up with a really cool set of new wheels that won’t fit on the car! Drop spindles typically don’t do any-thing to improve geometry, but they can still be a valuable tool. Mopars don’t respond to the same modifications as GM cars. Drop spindles (like these from Magnum Force Racing) can prevent messing up the geometry and bump travel resulting from lowering the car too much with the torsion bars. The arms allow a much better alignment to make the best of the new, lower stance. (Photo Courtesy Magnum Force Racing) Stock spindles vary in size, shape, and description, but the one thing they all have in common is that you probably already have them, so you don’t have to buy them. Some (like these first-generation Camaro GM spindles) are actually not so bad. They’re lightweight, compact, and have a modular format, allowing the use of different steering arms and brakes. Their major failing is that, in their original application, they’re much too short in relation to the rest of the suspension pickup points. This means very poor overall geometry and performance. (Photo Courtesy Chris Alston’s Chassisworks) Aftermarket tall spindles can be a great solution to geometry issues. They also come in a variety of styles, so make sure that all of their features complement your package before you buy. This billet aluminum Chassisworks tall spindle is a replacement for 1968–1972 GM A-Body cars and 1967–1969 GM F-Body cars (with a different steering arm). It offers improved suspension geometry as well as corrected bump steer with new steering arms. This is a non-drop spindle so it works very well with lowering springs. Many tall spindles are also 2-inch drop spindles. Combined with performance lowering springs, they may result in a car that is too low to be functional. Tie-rod end to wheel/tire clearance is also reduced; be sure to check how much room you have before you select drop spindles. (Photo Courtesy Chris Alston’s Chassisworks) The GM B-body spindle swap, popular in the 1980s and 1990s, has a serious bump steer issue that’s easy to see in this simplified diagram. The A-body inner tie-rod end is higher than the mounting point of the LCA. Because of this, the outer tie-rod-end pickup point needs to be higher than the lower ball-joint pickup in order for the tie rod to be in line with the instant center, for good bump steer. As you can see, the B-body spindle drops the outer tie rod ends even more out of line than they were from the factory. This results in the tie rod being grossly out of line. It doesn’t come close to intersecting the instant center, causing a significant increase in unwanted bump steer. Even if this could be cured, there is still a significant Ackerman issue caused by the steering arms being much too long. (Photo Courtesy Beaux Thompson) MacPherson struts have been all the rage since the 1980s. They’re inexpensive and speed up vehicle production time when compared to comparable SLA systems. Their geometry is arrived at differently than an SLA system but their performance can be similar. It’s hard to design a MacPherson strut suspension with poor geometry, but it’s also challenging to design one that’s truly outstanding. Engineers at BMW and Mercedes found they could improve upon the strut geometry by using dual lower ball joints and virtual pivots. This engineering is clever but well beyond the muscle-car-based scope of this book. Believe it or not, these AFX spindles are for classic A-, F- and G-body GM muscle cars. AFX 2.0, the latest version, is forged from 7075-T73 aircraft aluminum and is fitted with massive C7/ZR1 Corvette hub/bearing packs. A clean-sheet design, it generates outstanding suspension geometry when used with the proper support components. Even some of the best modern performance cars can sometimes benefit from geometry modifications. Take these gorgeous Raceseng C5 Corvette billet aluminum tall/drop spindles, for example. The drop may not be very practical on a street-based car, but they’re almost a must-have in World Challenge road racing. I liked the AFX tall spindles so much, I partnered with ATS to design application-specific steering arms and modifications to use them on A-body and G-body GM applications, like this Savitske Classic & Custom (SC&C) StreetComp-AFX package. (Photo Courtesy Gary Forman) This VariShock adjustable-rate strut is for 1982 to 1992 Camaros and Firebirds. There are no spring seats on it; these cars use struts in conjunction with conventional springs. (Photo Courtesy VariShock) Strut-equipped cars are particularly well suited to coil-over conversions, like this double-adjustable 1979 to 2004 Mustang unit.(Photo Courtesy VariShock) The last type is the tall dropped spindles. The term “tall” refers to a unit that’s taller than the original spindles for the purpose of correcting/improving the geometry. The actual height increase is generally between 1 and 2 inches. Most are still designed with a 2-inch drop, with the same pros and cons of any 2-inch dropped spindle. This class of spindles is most prevalent for GM A-body, G-body, and first-generation F-body cars. These tall spindles should be used with an appropriate set of upper A-arms that complement their non-stock geometry. The improvement in geometry and performance can be very impressive with spindles of this type. They’ll all improve negative camber gain, raise the roll center, and help stabilize it laterally. The degree to which they do so depends on the individual spindles chosen, the car they’re used on, and the rest of that car’s setup. Some improve bump steer by relocating the factory steering arms or by supplying new steering arms. But some actually make the bump steer much worse. Most are based on stock spindles, are made of cast iron, and accept stock brakes, bearings, etc. A notable exception is the American Touring Specialties (ATS) AFX tall spindle. It’s a forged 6061 T6 aluminum spindle designed to retrofit modern geometry, modern C5/C6 Corvette brakes, and massive C5 hub/wheel bearing packs to older cars. It’s not adapted from anything; it’s a clean-sheet design that allowed its designers to optimize every aspect to the last detail. This unit is a 1-inch dropped spindle, which is still enough to yield geometry gains but with better tie-rod end clearance than a 2-inch dropped spindle. Which spindle best suits your car depends on what brakes you intend to run, your target wheel size, and your budget, of course. (I address the specific attributes of the various spindles in Chapters 8, 9, and 10.) It’s always a good idea to ask questions before you buy spindles or any other aftermarket suspension part. How much of a change in negative camber gain can you expect when running your tall drop spindle of choice with 1-inch-lowering springs? Roughly, what will the new roll center height be? If your supplier of choice doesn’t know the answers, or if they’re the wrong answers, you might want to keep looking. If they’re not willing to take the time to answer your questions, they don’t deserve your money. How does installing a tall spindle package, tall-ball-joint package, or doing the G mod or Shelby mod affect the relationships of different aspects in the front suspension? As you change one thing, you know you’ll also be changing a lot of other things in a sort of chain reaction. As you change camber gain from positive to negative in bump, the instant center locations change as well, and the roll center is raised. This shortens the moment arm between the RC and CG. The front view swing arm (FVSA) is shortened as well, and must be prevented from getting too short. In conjunction with a higher roll center, it could induce too much suspension jacking and make the front end porpoise during heavy cornering. A well-designed system won’t let that happen, but it is one example of why more isn’t always better; just right is always better. The combination of changes results in a car with a lot less body roll, much better lateral grip, and much more precise and predictable behavior. Provided you also use the appropriate tires, springs, shocks, and alignment, it can now drive and handle like a new performance car. All suspension systems are a compromise between what’s ideal and what’s practical to build. In years to come, we’ll probably see dynamically adjustable suspensions that can alter not only shock dampening (as we have now on some high-end cars) but also spring rates, suspension arm length, camber and caster, and roll center location to fit the ideal requirements for a given situation at millisecond intervals. But that’s way beyond the scope of this book. Written by Mark Savitske
  3. x-series Fords - Front Suspension and Steering Guide Alignment There are three main settings of front suspension that affect the performance and drivability of your car: camber, caster, and toe. If your front suspension bushings and steering components are loose, worn, or broken, you should have them replaced before considering an alignment. An alignment performed on a car with worn-out tie-rod ends or deteriorated control-arm bushings is a waste of time and money. The settings will most likely change before the car gets out of the shop. Worn suspension and steering components are also a safety issue, so take care of these things as a matter of course. A worn steering gear won’t affect the alignment between the two front tires, but it will keep the driver from enjoying the benefits of the alignment. The worn gear will cause steering to be sloppy, less responsive, and even dangerous in some cases. This front suspension is a mix of off-the-shelf stock-car racing parts and custom fabricated and machined parts. Suspension analysis software and experience were combined to pull off this feat. Even the frame is completely fabricated. (Photo Courtesy John Parsons, Photography by John Ulaszek) Caster On a car with upper and lower control arms (as opposed to some strut suspensions that have only a lower control arm), the spindle pivots on the axis determined by the upper and lower ball joints. Caster is the forward or rearward tilt of the spindle on this axis as viewed from the side of the car. On most cars with this type of suspension, caster is changed by adjusting the strut rod or moving the upper control arm on its pivots using shims. A strut front suspension without an upper control arm uses an adjustable upper strut mount known as a camber plate to adjust camber and caster. When viewed from the side, if the upper ball joint is behind (toward the back of the car) the lower ball joint, the car has positive caster. Negative caster is when the upper ball joint is ahead of the lower. Caster has a tendency to cause the tires to move vertically a small amount as they are steered right or left from the centered position. This vertical movement acts to push the weight of the car off the ground, while gravity tries to pull it back down. The force of gravity, which is trying to pull the car down, pushes up on the tire. This upward force on the tire causes the spindle to rotate about its axis to the point that the forces on both the right and left spindles find equilibrium. This equilibrium is found when both tires are pointing straight ahead, assuming, of course, that the caster is the same on both sides of the car and there is nothing bent or out of alignment on either side. Both negative and positive caster can induce this self-centering action of the wheels and give the car more stability at higher speeds. Rubber suspension bushings deflect and distort under hard driving conditions. This distortion helps isolate road shock under normal driving conditions. This movement also allows the suspension geometry to change, hampering handling characteristics. Notice how the spindle is tilted and the tire is barely contacting the ground. Urethane or solid suspension bushings transfer road feel to the chassis. Solid suspension bushings also help the suspension keep its intended geometry. Notice how the tire is contacting the ground more evenly for better cornering traction. The top of the illustration shows the front spindle in extreme positive-caster position. The bottom of the illustration shows the front spindle in extreme negative caster. Positive caster is preferred over negative caster. The self-centering effect does not come from caster alone. It can also come from steering axis inclination. This is the same basic principle as caster, but in the front view of the suspension. If the axis of the upper and lower ball joints leans inward at the top, as a lot of cars do, there will again be a force trying to push up on the car. Some cars get this selfcentering effect using only steering axis inclination and zero caster. Camber Camber is the inward or outward tilt of the top of the tire as viewed from the front of the car. Negative camber is when the top of the tire tilts inward, and positive camber is when the top of the tire tilts outward. Positive camber is not desirable for handling, because it makes the outer edge of the tire dig into the pavement. If only the outside edge of the tire is on the ground, it does not produce as much cornering traction as having the entire width of the tire on the ground. With negative camber, when the top of the tire is tilting inward, the entire width of the tire has a better chance to evenly plant on the road surface for optimum traction. As with anything in life, negative camber is only good in moderation. Too much negative camber will have the inside edge of the tire trying to keep your car from sliding with unwanted understeer. Camber can be set on your car with an alignment. Camber-curve is something completely separate from the camber adjustment you get with an alignment (except in the case of a racebred suspension with adjustable controlarm pivot points). The camber-curve is affected by the length of the control arms and the control-arm pivot points. A positive camber-curve actually increases the outward tilt of the top of the tire during suspension articulation, which is completely undesirable and intensifies understeer. A negative camber-curve tilts the top of the tire inward during suspension articulation, which is much more desirable for improved handling around corners. I mention articulation because when your car is steered into the corner, the body leans. When the body leans, the outer front tire articulates upward in the fender opening. An extremely aggressive negative cambercurve can be bad, too. The key to a car that handles well is to keep the largest amount of the tire tread on the road surface, if possible. Negative camber settings help compensate for tire distortion under high lateral loads. This photo shows a front tire exhibiting positive camber; the top of the tire is pushing out. If you took a hard corner in this car, it would have understeer. Only the outside edge of the tire is biting the ground. This front tire is exhibiting slight negative camber. The top of the tire is tilted slightly inward. This car corners well. The entire width of the tire tread is able to get traction on the ground. It’s possible a little more camber would increase cornering performance. Toe Toe is the relationship between two tires on one end of the car as viewed from above. If, when viewed from above, both tires are parallel, there is zero toe. Toe-in is when the front of the tires are closer together than the rear, and toe-out is when the rear of the tires are closer than the front. Now that you know what zero toe, toe-in, and toe-out are, you need to know how the settings affect your car. If you aligned the tires with zero toe, the motion of the car moving forward will actually pull the front tires to a toe-out position from the distortion of the rubber suspension bushings and from road friction on the tires. To compensate for the road friction and movement of rubber suspension bushings, most factory cars are designed with a small amount of toe-in. The goal is to have the tires at zero toe for the intended average speed of the car. Factory alignment specifications are intended to minimize premature tire wear and to lower the rolling resistance of the tires. Since factory specs create less rolling resistance, fuel economy is increased. So, if you are planning on driving your Restomod across the United States on the Hot Rod Magazine’s Power Tour, you may want to have your car aligned to factory specs. With excessive amounts of toe, whether in or out, your tires will wear out faster and your fuel economy will decrease. Most cars are aligned with around 1 ⁄16-to 1 ⁄8-inch of toe-in. A setting of a 5 ⁄16-inch toe-in is quite a bit, but the small amount of extra toe-in increases high-speed stability. Consider 1 ⁄32-inch over the factory setting as a practical maximum. Toe-out has a tendency to make the car turn in faster. People looking for the fast way around corners will find benefits from careful experimentation with toe-out settings. Too much toe-out will cause the car to wander back and forth on the straights because the two tires are trying to steer in different directions. Wandering will get worse with increased road speed as a result of toe-out. Keep in mind that altering the factory alignment specs should only be done at the track. A little toe-out will help your car’s turn-in around corners and can also help to minimize understeer. What type of driving or racing you plan to do will determine what toe setting is correct for your application. Just as a warning, beware of the condition of your front suspension components. Worn or damaged bushings, ball joints, bearings, tie-rod ends, and other suspension components will act to alter your alignment settings. Getting your car aligned will not compensate for broken or worn parts. Street Alignment If you want your car to handle predictably on the street and your tires to wear evenly, you should go with the stock alignment settings. However, if you have replaced your rubber controlarm bushings with urethane or solid bushings, you may need less toe-in than the factory’s specs. The factory toe-in compensates for the flex and distortion of rubber bushings. Without the flex, you could try changing the toe-in to closer to zero. You may have to look around for a shop that does performance alignments to get the adjustments you want. A street performance alignment will wear the tires a little more quickly than normal, but the car will grip better on the street. For cars like the early Mustangs, what you’re looking for is the most positive caster you can get while keeping the camber between zero and about 11 ⁄2 to 2 degrees negative. For toein, stick with the factory specs unless you have firmer bushings. With polyurethane and similar replacement bushings, you may be able to move the toe closer to zero. You may need to experiment a little to get something that works for you, but these specs should get you in the ballpark. The caster recommendation above is done to increase high-speed stability and will increase turning resistance at the steering wheel. The camber is to increase cornering potential, but the further away from zero you get, the twitchier the car will be above about 50 mph or so. Racing Alignment If you plan to run your car on an open track or at an autocross event, the alignment can be more aggressive. A racing alignment is not good for street use. It will cause the tires to wear very fast, and it will be hard to control in a straight line or over rough roads, which makes it very dangerous on the street. If you are going racing, use common sense and trailer your car to the track. For tighter tracks, you may want to experiment with a little toe-out, but remember, a little goes a long way. On the longer, faster tracks, you may find that zero toe is a better choice. Again, experiment to see what works. Too much toe-out will increase the drag on the front tires and cause the car to wander at higher speeds. Anything over about 1 ⁄16 to 1 ⁄8-inch of toe-out is probably too much. The top of the photo shows the front tires in zero (neutral) toe. The car will drive straight and have very little rolling resistance. For demonstration purposes, the middle photo shows the front tires in extreme toe-in, and the lower photo shows the front tires in extreme toe-out. On the street, you will probably not be throwing your car into the corners as hard as you do on the track. The increased cornering speed increases your body roll and suspension articulation, so increasing the camber a little for extreme conditions may benefit your handling and your lap times. Adding a little bit of negative camber is good for increasing traction to your front tires. You can experiment with a little bit at a time. When driving on the street, negative camber increases your rolling resistance and will wear the inside section of tire tread, so the extra negative camber should be left at the track. Bumpsteer Basically, bumpsteer is the toe-in or toe-out caused by upward and downward movement of the suspension. Typical symptoms of bumpsteer include needing a steering correction if one wheel hits a bump; needing steering correction under hard braking; or needing wheel correction when cresting a hill. Bumpsteer comes from inadequacies designed into the suspension. Most cheap, economy cars designed in 2005 have less bumpsteer than sports cars designed in the 1960s. Suspension engineering has come a long way since then. Before explaining the technical aspects of bumpsteer, you need to learn about instant center. Visualize an imaginary line that travels through the upper control-arm inner pivot point and the upper ball joint, and then visualize another imaginary line that travels through the lower control arm pivot point and lower ball joint. These imaginary lines intersect at a point called the instant center. To have the ultimate front suspension and a steering system with zero bumpsteer, the imaginary line that travels through the inner and outer tie-rod assembly must intersect the instant center from the upper and lower control arms. That seems fairly simple, but there’s more to it. There are two more imaginary lines. The imaginary line that runs through the upper control-arm pivot point and the lower control-arm inner pivot point must intersect with the pivot point of the inner tie-rod end. The imaginary line that runs through the upper and lower ball joint must intersect the pivot point of the outer tie-rod end. This is all drawn out for you in the illustration supplied by Longacre Racing Products. A car with bumpsteer, which is almost every car, will have a change in toe when the tire encounters a bump or a dip in the road. (Illustration Courtesy Art Morrison) To eliminate bumpsteer, which is almost impossible with stock Restomod suspensions, the suspension parts all need to line up like this illustration shows. Even when the components are lined up, there is still a little tuning necessary from that point. (Photo Courtesy Jeff Butcher and Longacre Racing Products). Most factory suspension designers for mass-production vehicles have done a good job designing out bumpsteer, but limitations hinder their ability to eliminate it. Racing cars and high-dollar super cars have to perform well and demand a high level of engineering, so engineers go to extraordinary lengths to design steering systems without bumpsteer. Measuring bumpsteer can be done with some basic tools, but it is much easier with a Longacre Bump Steer Gauge. The gauge makes it easy to measure the amount of toe change during upward or downward travel of the front suspension. Bumpsteer is checked with the car properly aligned, with the wheels steering straight ahead. Start at ride height, and then move the suspension up 3 inches and down 3 inches. If the tie-rod assembly does not intersect the imaginary lines of the pivot points and the instant center, it will cause the spindle to turn inward or outward during suspension travel. This is bumpsteer. If you get your street car down to only hundredths of an inch of bumpsteer during its 6 inches of suspension travel, you’re doing awesome work. With stock suspension systems on most production cars, it’s almost impossible to attain zero bumpsteer. Most people try to get as close to zero as possible. Eliminating Bumpsteer There are several companies that offer bumpsteer checking equipment, as well as other alignment equipment, including Longacre Racing Products and Pole Position Racing Products. You can also build your own low-tech devices. These devices check the amount of fore and aft movement of the tire through the entire range of suspension articulation. Measuring bumpsteer is made easy with this Longacre bumpsteer checking equipment. With the springs removed, the suspension is jacked 3 inches up and 3 inches down from ride height. A dial indicator shows the amount of bumpsteer per inch of travel. The highlighted part is a bumpsteer correction kit offered by Baer Brakes. The kit is called a Baer Tracker and it replaces your tie-rod end with an adjustable rod end. A special, tapered stud for bolting the steering arm is included. Rod Ends Bumpsteer can be corrected, or at least minimized, by using spherical rod ends in place of the outer tie-rod ends. Shims of different thickness are used between the rod end and the steering arm to adjust the rod ends up or down, as desired to correct bumpsteer. In the past, it was necessary to drill out the taper in the steering arm and use a bolt to attach the rod end to the steering arm. In 2001, Baer Racing Inc. started offering adjustable tie-rod ends called Baer Trackers, which utilize spherical rod ends. They offer it for rack-and-pinion and reciprocation ball-steering systems. It takes the guesswork out of bumpsteer adjustment because it comes with special tapered bolts, shims, rod ends, and adjustment sleeves. Baer Trackers are available for early to latemodel Ford Mustangs, late-model Thunderbirds, Cougars, and more. Baer adds new kits to its Tracker line all the time, so if you don’t see your application covered, call and ask about it. Putting together the bumpsteer kit on your own isn’t worth the hassle of finding the correct heavy-duty tie-rod ends, customlength adjusting sleeves, and other adapters. However, if you want to correct or minimize your bumpsteer, and your application isn’t covered by Baer, it is possible to make your own system. You could attempt to get the necessary parts by looking at parts offered by stock-car racing parts suppliers. These suppliers offer tapered tie-rod adapters with “bump” spacers and rod ends to dirt track and asphalt racers. Be careful, because if the taper on the adapter is not correct for your steering arms’ taper, the adapter could break and cause serious damage to you and your car, or worse. Not all racing parts are appropriate for use on street cars, so proceed with caution. Bumpsteer Corrector Kits The bumpsteer can be corrected on some model year Mustangs, Falcons, and Cougars with a Bumpsteer Corrector Kit from Pro Motorsports Engineering and Mustangs Plus. When lowering these cars, the tie-rod angles change to become less than desirable. The kit moves the outer tie-rod pivot point forward and down for an improved angle. This kit changes the Ackerman angle, which quickens steering response, so it is great for handling. On the street, the quick steering and increased steering effort may be too much, so these kits are suggested for track use only. Rack-and-Pinion Bumpsteer can be corrected or minimized on cars equipped with rack-andpinion steering. The steering rack can be adjusted with shims to space it to the proper position. If shims won’t fix the bumpsteer, you may have to modify the steering rack mount, which can be costly and time-consuming. In some cases, the engine or other accessories will limit the amount you can move the steering rack. The first thing to check is the inner pivot points of the steering rack and outer tie-rod ends. They should intersect the imaginary lines of the front suspension and the instant center. Most likely they don’t, so you should attempt to move the rack to a position where they will be as close to those points as possible. Some aftermarket companies offering rack-and-pinion conversion kits for older cars try to adapt rack-and-pinion assemblies from late-model production cars. Some of those racks don’t come close to reducing bumpsteer; in fact, they may even make it worse. Control Arms and Front Suspension Kits When it comes to handling, upperfront control arms play a large factor. A few Fords are known to benefit from relocating the mount on the frame. Upper control arms can also be shimmed to adjust camber and caster. Many companies offer tubular upper control arms, but not all aftermarket control arms are created equal. Some front suspension kits completely do away with upper control arms for improved geometry and suspension leverage. Stock Control Arms Stock upper control arms are great for low-budget Restomod build-ups. Stock lower control arms can be used by drivers on any size of budget. Vintage racing historians have pointed out that the early Trans Am Mustangs had stock control arms with added bracing. If you are on a budget, you can add some bracing under the upper and lower control arms for added strength. Finding new replacement suspension components, such as steering components and control arms, is a common problem with building up older Fords with less popularity than Mustangs and Cougars. A company called Rare Parts, Inc. offers parts that are not reproduced by any other company. Rare Parts performs manufacturing, destruction, and cycle testing at its facility. Pictured here is a 1970-1971 Gran Torino control arm and a 1965-1968 Galaxy steering arm. (Photo Courtesy Rare Parts, Inc.) Control-Arm Relocation – Shelby mod Probably the most common suspension modification is the Shelby controlarm relocation, also known as the “Shelby mod.” According to history books, Ford engineer Klaus Arning came up with the idea and passed it onto Shelby American, which applied it to the Shelby Mustangs. Since then, people have applied this modification to early Ford Mustangs, Falcons, Rancheros, and Cougars. The modification moves the upper control arm down, which lowers the center of gravity, lowers the car approximately 5 ⁄8-inch, reduces body roll, and increases negative camber gain. These are all considered positive enhancements to most front suspensions – especially for front suspensions that were adapted from early 1960s-engineered six-cylinder cars. Aftermarket companies and Internet websites offer templates and directions that show where to drill 17⁄32-inch holes in the shock towers to move the upper control-arm cross-shafts. The diagrams for performing the Shelby mod on 19641 ⁄2 to 1970 Mustangs are included in this chapter. These measurements were designed and used back in the 1960s and were also designed for cars using stock upper control arms. Today, aftermarket suspension companies have similar diagrams, but with different measurements. Companies offering aftermarket control arms and other front sus pension parts have found better placement of the control arms to get the ultimate benefits out of their modified geometry. In some cases, the relocation holes interfere with the Shelby mod hole. If you haven’t purchased upper control arms yet, but you plan to do so in the future, it might be best to wait on performing the mod. If you’re planning to keep stock upper control arms, and plan on performing the Shelby mod, you should take a few things into consideration. Since the mod lowers the car approximately 5 ⁄8- inch, it’s enough to cause problems with the tire fit for larger- than-stock tires. It also puts the upper ball joint at a severe angle and increases the unwanted bumpsteer problems already present with the stock suspension’s pivot points. This illustration shows the dimensions for performing the Shelby mod, including lowering the upper control arm to improve the camber curve of the front suspension. These examples are for the driver’s side of the car, but the passenger side would use the same dimensions. The Shelby control-arm relocation has been performed on this Mustang shock tower. The upper holes are in the stock location, and the lower ones are the Shelby mod holes. The big notch in the lower section of the tower brace was performed by Griggs Racing during serious modifications. The Shelby mod also requires you to use different alignment specs. You may need to find a reputable shop that specializes in custom alignments because some shops don’t like to align vehicles with modified suspension geometry. As long as you follow the Shelby mod diagram, the Shelby “R” alignment specs will apply. Shelby Mustang specs (with the Shelby mod) are from 2 to 3 degrees (depending on whom you talk to) positive caster, 1 degree negative camber, and 1 ⁄8 inch toein. If you perform this mod on a vehicle other than a Mustang, you’ll need to consult a specialty shop for the correct alignment specs for your application. The mod lowers the control-arm shaft, which increases the angle of control arm and pivots the upper ball-joint stud close to its limit at full “bump” (the upward movement of the tire and suspension when the tire hits a bump). In some cases, the upper ball-joint stud can bind and break. Pro-Motorsports Engineering and Mustangs Plus offer Negative Wedge Camber Correction Kits, which change the angle of the upper ball-joint and allow for more aggressive control arm relocation for an increased negative camber curve. This mod works best with less shock travel to limit droop because the droop has an adverse effect on steering geometry Aftermarket Control Arms and Suspension Kits Most Restomods are driven harder than the Ford engineers ever intended. The torsional stresses that come from cornering and braking forces can wreak havoc on the stamped-steel stock control arms. You may think, “Why would I need aftermarket control arms on my car? Shelby’s racecars worked fine for road racing with stamped steel control arms.” With tire technology and braking force from satellite dish-sized rotors, you will be demanding more from a stamped control arm than Shelby and Bud Moore cars did during good days at the track. Since the 1990s, aftermarket companies have been building control arms designed to handle more stress and include better ball-joint angles. These are great for people who want to drive in a straight line and drive hard through the corners. Be careful, though; there are some aftermarket control arms designed for street rods and air-bag suspension systems that lack integral strength for Restomod applications. The companies mentioned below are the current companies offering performance control arms for Mustangs, Falcons, Comets, Cougars, Cyclones, Fairlanes, Montegos, Rancheros, Torinos, and Mavericks. Some companies offer control arms that are part of a whole kit, or offer coil-over systems that use their control arms or completely replace the upper arms with the coilover unit. Those will be mentioned later in this chapter as suspension systems. Total Control Products If you have a Restomod or even a slight interest in one, you probably know about Total Control Products. The company started back in 1995 and offered high-quality performance suspension parts designed for street and track use. At that time, the Ford guys were not willing to cut up their cars or modify them in any way that couldn’t be easily reversed. Total Control took this to heart and built top-notch suspension systems with strictly bolt-on parts. You can see that the Shelby mod relocates the upper control arm, which lowers the car about 5 ⁄8 of an inch due to changing the spring-perch position. It also puts the upper ball joint at an extreme angle when using the stock control arm. Total Control Products offers a fully adjustable coil-over front suspension system with tubular upper and lower control arms, and heavy-duty strut rods. The kit uses Kevlar-injection molded rod ends to achieve movement without the deflection found in original rubber bushings. This kit installs without irreversible modifications. Global West offers upper and lower tubular control arms with its Category5 coil-over kit (shown here). The kit requires the installer to drill a few holes in the shock tower, so Global West includes quality metal templates and detailed instructions. (Photo courtesy Global West Suspension Systems) Total Control Products offers tubular upper and lower control arms for muscle car-era Mustangs, Falcons, Comets, Cougars, Cyclones, Fairlanes, Montegos, Rancheros, Torinos, and Mavericks. You get what you pay for with these parts – they don’t cut corners. Total Control Products control arms are designed to have less flex than the stock control arms because they’re assembled from the best materials and components, and they’re TIG welded for strength and durability. The upper control arms have strong mount provisions to use the stock coil-spring set-up (if you choose not to use their coil-over conversion kit). The upper ball-joint angle has been designed to safely operate with the suggested lower cross-shaft location for increased negative camber gain. For strength and durability, the upper and lower control arms are equipped with high-quality injection-molded, Teflon-impregnated Kevlar rod ends. These do not distort like the factory bushings, so your handling will not be erratic. The lower ball joint is a heavy-duty screw-in type (common in stock-car racing) for easy serviceability and replacement. Global West Global West is one of the most diversified aftermarket suspension companies. It makes parts for Fords and GMs, and the performance of its products shows that the company is familiar with both manufacturers. The Ford years span from 1964 to 1973 and 1978 to 2002. Global West calls its suspension systems Negative Roll Systems. This refers to the negative camber gain designed into its systems. Muscle car-era models were plagued with positive camber gain, and the Global West systems are designed to fix that problem. Global West upper control arms are made from tubular steel, and they improve suspension geometry by not deflecting under heavy cornering loads like stamped stock control arms. The length of the arm is modified from stock, so the front tire will be kept on the pavement over the complete camber curve. Global West suggests lowering the control arm location, similar to the Shelby mod. The upper arms are equipped with billet cross-shafts and Del-a-Lum (Delrin and aluminum, pronounced Dellaloom) bushings, which allow smooth, deflection-free control arm articulation. Global West offers two different lower control arm options. One option is a stock lower control arm with welded boxing plates for strength. These control arms also feature spherical aircraft bearings in place of the control-arm bushings for non-binding, full-range motion, and a new standard ball joint. The second option is a full tubular control arm with a spherical aircraft bearing, along with a screw-in ball joint, like the ones used in stock-car racing. Global West also makes coil-over kits for 1964 through 1973 Mustangs; 1962 through 1967 Falcons and Rancheros; 1967 through 1973 Cougars; 1968 through 1971 Montegos; 1967 through 1971 Fairlanes/Torinos; 1970 through 1977 Comets/Mavericks; and 1975 through 1980 Monarchs/Granadas. Global West calls its coil-over kits Category 5 (or Cat 5) suspension kits. It still requires the use of an upper control arm, but one with a specific design. The extralong coil-over shock assembly replaces the conventional short shock and coil spring combination. The shock angle was changed for increased performance and leverage. Global West also offers this kit with large-diameter rotors and multiple-piston Wilwood disc brakes for a more complete package. Revelation Racing Supplies (RRS) Revelation Racing Supplies (RRS) is an Australian-based company with new distribution in the United States. Don’t let its new arrival throw you for a loop; these guys have been around for years. Every product RRS produces is tested by Australia’s stringent standards to actually perform and be stronger than the part it is replacing. It would be interesting to see how American products would perform on these tests. RRS front-suspension kits allow you to ditch old, inferior technology and replace it with a coil-over strut set-up. RRS offers different levels of front strut kits for Mustangs, Falcons, Comets, Cougars, Fairlanes, Rancheros, and Mavericks. The kits all replace the existing upper control arms, coil springs, and shocks. In the place of the old equipment, the kits include coil-over struts that bolt in the stock shock mount location, late-model spindles, disc brakes, calipers, brake hoses, and all necessary hardware for an easy bolt-in application that does not require any fabrication. Slotted disc-brake rotors are available in diameters ranging from 11.3 to 13.2 inches. The brake calipers are available in single- and dual-piston floating calipers, as well as four-piston fixed calipers. As for struts, you can choose between KYB heavy-duty and Koni adjustable units. RRS also offers a strut-rod kit with bearing ends to complement the strut kits. Revelation Racing Supplies (RRS) offers different levels of front suspension systems for shock-tower-equipped cars. These completely do away with the upper control arm. The kit doesn’t require any fabrication and uses serviceable factory tie-rod ends. (Photo Courtesy Revelation Racing Supplies) Since the RRS strut front suspension kit totally negates the need for the upper control arms, you can modify the shock tower with an RRS shock-tower notching kit. It creates enough room for the big-block or modular motor you’ve always wanted to install. (Photo Courtesy Revelation Racing Supplies) Griggs Racing coil-over front kit totally relocates all suspension pivot points and features weld-in uppercontrol-arm mounts and a lower K-member. The new steering rack mounts in front of the spindle centerline and uses a racing-style sway bar. (Photo Courtesy Mustang Don’s) RRS front suspension kits offer improved suspension geometry, reduced (if not eliminated) bumpsteer, adjustable ride height, and up to 5.5 inches of clearance per side with an RRS shock-tower notching kit for big-blocks and Modular engines, all without changing track width. The system works with the stock steering linkage, or it can be used with the RRS performance rack-and-pinion kit. Fat Man Fabrications Fat Man Fabrication is probably best known for its Mustang II-type front suspension systems. The company now offers a front strut kit for select shocktower-equipped Ford models from 1964 to 1973. Fat Man’s new set-up is a bolton kit, instead of the invasive Mustang II kit that requires moving the engine up and forward, which adversely affects weight distribution and handling. Fat Man claims that this kit allows an adjustable drop of up to 4 inches (with optional parts) and it is designed to operate with zero bumpsteer. That’s quite a feat, and a far cry from the undesirable bumpsteer characteristics of the stock Mustang. The kit also allows you to use a stock oil pan and stock sway bar without welding. Since the springs are smaller in diameter than the stock spring, this kit allows the builder to trim the shock towers for wider and larger engines. The kit includes a tilt steering column, coil-over springs, tubular lower control arms (with new ball joints and bushings), upper strut mounts (with adjustable camber), a steering shaft (with U-joints), special steering arms, a rackand-pinion mounting bracket, and mounting hardware. You supply a steering wheel with GM splines; a 1981 to 1986 Escort rack-and-pinion system; and 1994 to 2002 Mustang disc brakes, spindles, and struts. Griggs Racing Products, Inc Known more for late-model Mustang racing parts, Griggs Racing Products also has a full line of performance suspension parts for the early Mustangs. Griggs Racing sells different kits for different types of racing, including street, autocross/open track, and American Iron (Pro-Road Race). Each version is specifically designed for the intended purpose. Bruce Griggs advises having a good idea of what you are going to do to a car before purchasing a kit. Changing your mind halfway through or at the end of a project gets very expensive, and this advice applies to all parts of a project. It is especially true with Restomods. The Griggs packages are more invasive than just bolting on a pair of control arms. These kits take front suspension to a whole new level. The kits completely replace and relocate the front suspension components and pick-up points. In fact, you can completely remove the shock towers if you choose. The suspension pieces are much stronger than the original equipment, so you get precise geometry for predictable handling. Anti-dive, roll-center, and camber-gain problems associated with the stock suspension are addressed with this kit. If you don’t mind breaking out the welder and cutting torch, this kit is a great improvement, and it works best with the rear suspension kit Griggs offers. The front-suspension kit is called the GR-350 kit. It comes with a tubular K-member, bumpsteer adjustment kit, upper and lower tubular control arms, mini-tower brake kit, coil-over shocks and springs, adjustable racing-style sway bar, spindle and hub assembly, and a rack-and-pinion steering assembly. The kits come in three different levels: Street, Autocross/Open Track, and American Iron (Pro-Road Race). They are designed for the 1965 through 1970 Mustangs. Martz Chassis Gary Martz of Martz Chassis builds drag race and road race subframes for all kinds of cars, including a weld-in subframe unit for Mustangs. Martz’s Rally and Road Race chassis for the Mustang is the center of attention for this section. The installation is a little more involved, but you might feel the results are worth it. Not only is the Martz set-up a huge leap in suspension geometry engineering, it also has a much stronger and more rigid frame. Martz offers an optional Wide-Track frame, so you can run latemodel offset wheels. The frame has extra-long transmission mounting pads, so you can mount just about any available transmission. There are also different mounts for most Ford engines. The customer can choose from production or aftermarket brakes from Baer Racing or Wilwood, and the sway bar is a custom 1- inch stock-car-style unit. The rack-andpinion is a Mustang unit, and it’s available in manual or power versions. Martz Chassis saw there was a market for upgrading the front suspension to something other than a Mustang II set-up. This front clip replaces the weaker stamped-steel frame for increased strength. (Photo Courtesy Martz Chassis) Martz Chassis doesn’t use any Mustang II suspension parts; it makes its own spindles using heat-treated 4140 chromemoly. There is no anti-dive built into the subframe, but some feel anti-dive is overrated anyway. The range of caster and camber is unlimited, but typically the suggested caster ranges from +2 degrees to +6 degrees, and the camber range is zero degrees to + or – 4 degrees. Martz tested its subframe for bumpsteer, and found none for 3 inches of travel. The set-up can be ordered with heim joints or with urethane bushing ends. Martz has been in business for 33 years, so replacement parts are readily available and the system has been street- and track-tested. Springs Your front coil springs are one of the most important contributors to the handling characteristics of your Restomod. For this reason, it is crucial that you decide on a spring rate that is right for your ride. A spring that is too soft for the weight of the vehicle is great for drag racing, where racers need the weight of the vehicle to transfer from the front suspension to the rear suspension for ultimate traction. Yet, Restomods do more than just drive in a straight line— they rely on the front tires to keep them on track while entering and exiting a corner. A soft front coil spring will also give you excess body roll and cause your inside tire to lose traction in the corners. Restomods are intended for street use, just as much as the track, if not more. If your front coil springs have a rate that is too high for the weight and set-up of your car, they will give you a harsh ride on the street. Springs that are too stiff may not allow your car to have the body roll it needs to plant the outside tire in a corner. Without traction of the outside tire, the car can push and generate uncontrollable understeer. Choosing the right spring for your application is not easy. If I told everyone to run a 650-lb front coil spring, I’d be performing a disservice. To make an accurate recommendation, I would need to know your rear spring rate, front and rear shock dampening, bushing types, tire compounds, etc. Every car is different. Sure, you could throw a set of 650- lb front coil springs in your Maverick. You might get lucky and they might be perfect. In the end, consulting the technical department of your favorite suspension company could help you get the exact spring you need. If your suspension company doesn’t have an educated spring recommendation for you, you may want to just get in touch with a reputable spring company. Coil Spring Basics There are two different types of coil spring: linear and progressive. They can be identified by looking at the windings. A linear coil spring has equally spaced coils throughout, except at the very end of the spring. The progressive coil spring has coils that are wound tighter on one end of the spring than the other end. Coil spring rates are identified by how much weight is required to compress the spring 1 inch. A 600-lb spring will require 600 lbs to compress it one inch. A 600-lb linear rate coil spring would require 1,200 lbs to compress the spring 2 inches. A 600-lb progressive rate spring might require 1600 lbs to compress the spring 2 inches. Linear rate coil springs are used on most production cars. Typically, progressive springs are used in racing applications. Coil springs are available in 400 to 3,200-lb rates. The higher the rate, the harsher the ride will be. Typically, only purpose-built road-racecars need more than 800-lb front coil springs. The spring on the right is linear; i.e., its coils are uniform throughout. The spring on the left is progressive; notice the change in winding density. Both types can be used in the front or rear, depending on the suspension type and application. When you’re trying to increase the performance of your suspension and lower the stance of your car, you should buy some springs designed to perform both tasks at the same time. If you are simply looking to lower your car, you can do it the old-fashioned way by cutting them. Heating your coil springs to lower your car is unsafe and a bad idea. The image of the coil springs in this section shows the ends of the spring are slightly bent to keep the ends fairly flat. The ends fit into pockets in the frame, shock tower, or spring retainer. When cutting coil springs, don’t start out cutting two complete coils, because you may end up lowering your car 5 inches by accident. Cut the spring in one-half coil increments. You may need to install the spring a couple of times before you achieve the desired ride height. Safely remove the springs from your vehicle. Use an acetylene torch to cut half of one coil. Now you need to bend the end of coil so it will seat in the spring pocket. Heat one-half coil leading to the end of the spring where you made your cut and quickly bend that section down toward the rest of the spring. If you can, turn the spring over and push the spring down onto the concrete to bend the coil. Warning: Don’t quench your coil spring with water or oil! Let the spring cool slowly in the air. If you quench it, the spring will lose its ability to support the weight of your vehicle. After changing ride height, you will need to have your suspension aligned. Stock Springs Stock front coil springs typically deliver a comfortable ride for the majority of the population. For Restomodders, the rate may be too soft or the ride height might be too high. In the past, it was a cool trick to run “air conditioning” or “big-block” springs for better handling. A stock coil spring for a car equipped with air conditioning and/or a big-block typically has more spring rate to help compensate for the extra weight. Since this is not an exact science, aftermarket springs may be a better choice. These parts are from a 1965-1966 Mustang steering box. Ball bearings roll around the worm gear and recirculate in and out of the ball nut through the transfer tubes shown. As the steering shaft turns, the ball nut moves up and down the shaft. The teeth on the outside of the ball nut turn the sector gear and steering arm. Aftermarket Springs – Available Rates There are so many companies offering different springs with different weights that it makes sense to tune your suspension with aftermarket springs. Some companies prefer lower-rate springs than others; each company has its own idea of what is best for each application. One company may believe a car should be set up with more oversteer, while another company may believe a car should be set up with more understeer. Since each company has a different idea of what rate is best for each application, you may want to pick a reputable company to ask for help. If you talk with too many companies, you may get too much information for your own good. If you aren’t building a full-on competition racecar, you don’t need too much information. Keeping it simple is not a bad thing. With the right help, you can get your optimum coil spring rate within 100 lbs, which is more than adequate for most Restomods. Ball Joints Serious racers have been replacing stock-style bolt-in ball joints with screwin ball joints. The welding and machining required to perform this modification should be done by a professional. The screw-in ball joints are stronger and easier to replace in a hurry at the track. Cobra Automotive offers control arms already modified with screw-in ball joints for early Mustangs and Cougars. Compared to the stock Ford ball joints, the screw-in racing-style ball joint has a larger body and stud. The only way to accomplish this installation is to purchase screw-in ball joints and ball joint adapter rings. You have to weld the screw-in ball joint sleeves into the lower control arms. Since the screwin ball joint may have a different taper (depending on application and ball joint used) on the stud, the spindle will have to be re-tapered. A reputable machine shop should be able to perform this task, but they might have to buy the special drill-bit to perform the modification. Keep in mind that the screw-in ball joint has a different pivot point than the stock Ford ball joint. This modification will change the suspension geometry. Installing a suspension part designed for the stock ball joint might not benefit from the changed pivot point, so be aware of this before you do the modification. Steering Car builders often overlook the steering system. The stock steering is great for a family cruiser, but if you’re going to drive your Restomod on a road course or just want better performance on the street, aftermarket steering systems are available. You may have either a manual or power-assisted steering system on your car. There are two types of steering systems: recirculating-ball gearbox and rack-and-pinion. The power steering system consists of a steering pump, fluid reservoir, hoses, and in some cases there is an add-on power steering cylinder and control valve. Manual steering gearbox systems don’t work very well on Restomods, since the Restomod tires are generally wider than stock which makes them more difficult to turn. Upgrading your recirculating-ball manual system to a power-assisted system requires a power steering box, power steering pump, and in some cases, you’ll need to upgrade to power-steering-specific tie rods, center links, idler arms, and pitman arms. You can buy these specific parts from Moog and Rare Parts. Most Restomod candidates came with the kind of power steering that used a recirculating ball steering box. The steering boxes in 1964 to 1970 Mustangs, Comets, Falcons, and Cougars, and in 1967 to 1968 Fairlanes and Montegos were non-integral units. They all had an add-on assist-type power cylinder and a control valve. The only difference between the actual power and manual steering boxes were the ratios. The fast ratio manual box was the same as the power steering box. In a recirculating ball steering system, the steering shaft (attached to the steering wheel) turns a worm gear inside the gearbox. Inside the gearbox, there’s a nut (a cage that surrounds the worm gear) with teeth on the inside and on the outside. The nut moves forward and backward inside the gearbox. The internal threads on the nut coincide with the external threads of the worm gear. The worm and the nut are separated by a trail of ball bearings that recirculate in and out of the nut, while creating a rolling screw-like thread. The ball bearings allow the worm to turn inside the nut with very little bearing surface area for smooth operation. The teeth on the outside of the nut pivot the sector shaft, which attaches to the steering pitman arm. A power-assisted steering gear puts fluid pressure on the nut to assist its movement inside the steering gearbox. Less effort is needed for applying to the worm gear (meshed with the steering shaft, attached to the steering wheel) to move the nut forward and backward inside the steering gearbox. Every steering system has a steering ratio. The ratio of the steering box or rack determines how much the wheels turn in conjunction with how much you turn the steering wheel. A wide-ratio (compared to a close-ratio) steering system will require more full steering-wheel revolutions to turn from lock to lock. This could mean as many as six complete revolutions on a 22:1 wide-ratio manual box for a 1967 Fairlane. A typical Ford 16:1 close-ratio steering box will require 3.75 full revolutions of the steering wheel to turn from lock to lock. This might not seem like a big difference, but considering how much less the steering wheel needs to be turned on a road course, a close-ratio box makes driving much less work. Road-course driving can be physically draining, so the less energy spent on turning the steering wheel, the better. Power-assisted steering systems have a high- and low-pressure circuit. The power steering pump pressurizes the fluid up to 1,350 psi and forces it through the feed line into the steering gearbox. The low-pressure circuit is the return line from the steering gearbox to the fluid reservoir. From the reservoir, the fluid is sucked back into the pump. The terms “rear-steer” and “frontsteer” refer to the location of the steering linkage or rack-and-pinion. The linkage on a rear-steer system is located behind the centerline of the spindles, and the front-steer linkage is located in front of the centerline of the spindles. Before the introduction of rack-and-pinion steering, Ford had been a big proponent of the front-mounted strut rod suspension. Due to space constraints caused by strut rods, most of the early Fords are rear-steer cars. Most newer Ford cars have front-mounted rack-and-pinion steering systems. Until 1966, most Fords (except fullsize Fords) had long-shaft steering boxes, identifiable by their approximately 30-inch-long shafts, when Federal Motor Vehicle Safety Standards required a collapsible steering column. In front-end collisions, the long shaft could be pushed toward the driver with terrible results. In 1967, Ford switched to using very short shafts that used a rag joint to interface with the collapsible steering column. If you need a replacement for your worn steering box, check out this offering from Flaming River. The company offers completely new steering boxes—not rebuilt— for 1965-1970 Mustangs. (Photo Courtesy Flaming River) A power steering gearbox can be set up with custom-tailored efforts. The effort is the resistance you feel in the steering wheel when you turn it. If the steering box is not built with efforts, you’ll be able to turn the steering wheel with one finger, even when the car is sitting still. This might sound good, but it’s much better to have a little feedback from your steering so you know how your car is reacting to track conditions. Contact Flaming River Industries if you want to replace your old, worn Mustang 19.9:1 or Falcon 22:1 ratio steering boxes with a close-ratio 16:1 recirculating-ball steering box. Flaming River saw a void in the 1965 through 1970 Mustang steering market, so they started building gearboxes from brand-new parts. Even the cases are new. They used better materials and re-engineered a few of the areas of the box for better performance. SCOTT CHAMBERLAIN’S 1985 FORD LTD LX When you mention something about a “hot rod,” most people don’t envision a four-door. To go a little further, most people wouldn’t think of an LTD as a “hot rod.” Jefferson Morris is a guy who thinks outside of the box. He built most of this LTD before Scott Chamberlain took ownership. Since then, Scott has made this car his daily driver and has taken the performance even further. This is not your grandma’s LTD, or an LTD II, or even a Fairmont – it’s a Ford LTD LX. A total of 3,260 were built between 1984 and 1985. Ford took the LTD and dropped in a 5.0 HO engine, AOD transmission, 3.27:1 limited-slip rear end, sport-tuned suspension with larger sway bars, upgraded bucket seats, center console with floor shift, factory tach, special interior trim, and blackened external trim. That’s how the car started. It’s been taken further into the performance spectrum since the day Jefferson Morris had the keys in hand. Since the Fox-bodied LX shares many parts with the 5.0 Mustangs, many performance parts simply bolt on. Parts are from the aftermarket as well as Ford. One of the first things to get swapped out was the AOD for a T5 5- speed with a 1987-93 Mustang pedal set, 1993 Cobra clutch, Forte’s adjustable quadrant, and MAC short shifter. The car has 140,000 miles on it, so the engine had to be updated sooner or later. The current engine is a 1994 Mustang GT 5.0 with AFR 165 heads stuffed with Crane 1.7 roller rockers. The intake manifold is a Ford Motorsport Cobra intake with ported lower runners. Feeding the intake is a MAC cold air kit, Pro-M 75-mm MAF sensor, 65-mm Ford Motorsport throttle body, and 24-lb/hr injectors, all handled by a stock 1987- 1993 Mustang A9L-calibrated ECM. Scott Chamberlain’s 1985 LTD LX is one of 3,260 LXs made from 1984 to 1985. The LTD is built on a Fox-body platform, so many production and aftermarket Mustang parts simply bolt on. In current form, it rivals performance cars of its time, but it has four doors. (Photo courtesy Dave Moore) The LX is subtle. If you didn’t know better, you may think it’s just an LTD with 17×8-inch Cobra wheels. The car has all the performance angles covered and Scott’s not afraid to drive it, so watch out – this may be the only end of the car you will see. (Photo courtesy Dave Moore) This LX is powered by a modified 5.0-liter HO engine from a 1994 Mustang. It knocks down 20 mpg, runs the quarter mile in 13.79 seconds, and glides down canyon roads with speed and confidence. (Photo courtesy Dave Moore) The exhaust is handled by MAC shorties connected to a stock 1987-1993 Mustang H-pipe to 3-inch single pipe (due to clearance constraints), Dynomax Ultraflows, and 1999 Cobra dual tips. The cooling is handled by a Mark VIII fan (with a trimmed shroud) hooked to a Delta Current Controls FK-35 unit, which takes the high amp surge out of the Mark fan ramping up. The air conditioning is still intact and works great. The battery has been relocated to the trunk, and gets its juice from a 3G 130-amp 1994 Mustang alternator. The front suspension was upgraded with 1996+ Mustang spindles, 1996+ Mustang lower control arms, inner and outer tie-rod ends, MAC adjustable caster plates, LX springs (high-rate from the factory), and polyurethane bushings throughout. KYB shocks and struts adorn all four corners. The front sway bar is still the stock unit since it was so stout to start with. The rear suspension consists of a Ford 8.8-inch with 3.73:1 gears and an axle girdle differential cover, box-welded stock control arms, and a 1998 Cobra rear sway bar. The LTD features 1994+ Mustang Cobra 13-inch front rotors, PBR dualpiston calipers, and late 1980s Lincoln Mark VII 10.5-inch rear discs, all controlled by a Lincoln Mark VII master cylinder and an adjustable proportioning valve. Scott notes that with Lincoln Continental parking-brake cables, the parking brakes actually work. Bolted to the brakes are stock 1999-2001 Mustang Cobra 17×8 wheels wrapped with 245/45R17s all the way around. The interior currently has most of its stock luster, but it was upgraded with a Momo Monte Carlo steering wheel, 140- mph police speedometer, AutoMeter gauges, CD/tape player combo from a 2000 Ford truck, modified console for new manual shifter, Cobra floor mats, and a dead pedal from 1987-1993 Mustang. Scott’s car sticks out in a crowd because it’s not your typical late-model Restomod, but it’s subtle enough to avoid attracting undue attention from white-and-black four-door sedans. It’s a great mix of luxury, hot rod, and corner carver. It has enough room to transport more than just a driver and one passenger, while knocking out 20 mpg and running a 13.79 in the quarter mile. Power Steering Pumps Power steering pumps provide the pressurized fluid necessary to drive power-assisted recirculating-ball steering gearboxes and rack-and-pinion steering units. Stock pumps are decent for normal street driving. When you start running your car at track events, you may want to look into upgrading your pump. Upgrading a power steering pump is rarely a simple bolt-in procedure, due to hose and bracket configurations. In some cases, you can utilize factory brackets from a different application. Thompson Slipper Pump The Thompson “slipper” pump was offered from 1965 through 1977. It has been called “a bucket-type pump,” as well as a few other names I can’t print here. The pump worked well for stock applications. The racers who didn’t ditch it put up with it because there wasn’t a good performance system available. The term “slipper” comes from the eight slipper pistons that are spun around by a rotor inside the internal chamber, somewhat like a vane-style pump. This pump will work fine for most applications, but if you’re going to start running 20- minute sessions on track days, where the fluid can reach 250 degrees, you may want to think of upgrading to a latermodel pump. Those kinds of temperatures can wreak havoc on the pump’s internals. The engineering team probably never envisioned a high-revving 500-hp small-block Maverick running around a road course. This is a Thompson “Slipper” power steering pump. The name comes from the design of the internal slipper pistons. If you’re planning on periodically running 20-minute sessions at your local road course, you might want to think about upgrading to a new-style pump. Ford Corporate II (C2) Pump The Ford Corporate pump used on V-8s from 1978 through 1995 (later on V-6s) is known as the C2 or CII pump. The C2 pump was designed to work better in conjunction with power-assist rack-and-pinion systems. It is known to have problems aerating the power steering fluid, which causes it to groan in some cases. Other than that, it performs great for most Restomods. If one of these fails on you, you might try replacing it with a Saginaw P-series pump (a GM part) with the Ford #F4UZ3C511A pump bracket, the correct pulley, adapter hoses, and some shimming. If you are sticking with the C2 pump, and you have had problems with fluid blowing out of the vent in the top of the filler cap during racing conditions, you may need to modify the neck of the pump to add a little more expanding room. Cut the top half of the plastic neck off, add a 9-inch heat-resistant 5- ply silicone hose to the neck on the body of the pump, then install the top half of the neck (with the filler cap) to the hose. Use high-quality hose clamps and don’t over-tighten them. Basically, you just want to add length to the filler neck to keep the power steering fluid away from the bottom of the vent in the cap. Don’t plug the vent hole. That will cause a whole new set of problems—the system needs to breathe. Saginaw TC Pump This power steering pump is produced by Saginaw for many auto manufacturers, including Ford and GM. If you plan to race your car on a road course, you might want to take a serious look at upgrading to a Saginaw TC pump (transverse-bearing compact pump). These pumps are well suited for racing and high-performance street applications. TC pumps are used on most domestic cars produced after 1993 with powerassisted steering. It’s easy to find a TC pump to use on your car, but be careful. Saving a few bucks might cause you some headaches. Factory production TC pumps are built specifically for the pressures needed for the steering boxes or rack-and-pinion units they were mated with from the factory, so not all TC pumps are the same. Most have lowdrag bearings on both ends of the shaft. One TC pump in particular has a front bushing instead of a bearing. The bushing creates more friction, causing pow er-robbing drag, and wears out faster than a bearing. Luckily, it can be easily identified by its 3 ⁄4-inch shaft. Using production TC pumps can be challenging since not all of them have the necessary fittings needed to adapt them to your system. Some come with plastic reservoirs mounted directly to the pump, while others use remote-mounted plastic reservoirs. If you want fewer headaches and better performance from your steering system, spend the extra money to get one of the many available aftermarket TC pumps, which are available in cast-iron and aluminum for weight savings. Aftermarket TC pumps usually come with high-temperature seals and O-rings, as well as low-drag bearings (check with the individual company for specifics). A few companies build TC pumps with different pressures and flow rates that match the performance steering boxes. In that case, get matching components from one manufacturer for best results. This is a Ford Corporate II power steering pump. It’s also known as a “C2.” This pump has been modified by a road racer to prevent fluid from blowing out of the vented cap. The high-temp silicone hose moves the cap further away from the splashing fluid. The pump on the lower right is a cast-iron Saginaw TC power steering pump built by AGR. The pump held in the hand is an aluminum KRC Racing pump. Aftermarket TC pumps are available with all the proper fittings, pulleys, and hardware you will need to hook them up to your steering system. To save you headaches, there are aluminum-mounting brackets available for the 289, 302, 351, and 400 engines. There are even universal brackets if you can’t find one that suits your needs. Not all brackets give you room for the locally mounted reservoir in the position you need, so a little research could pay off, or you could run a remote reservoir. Some options for aftermarket TC pumps are listed below: DSE Modified TC Power Steering Pumps Detroit Speed & Engineering builds brand-new (not rebuilt) pumps for performance applications. DSE has extensive experience with power steering systems and builds each pump by hand, not on an assembly line. DSE offers TC pumps in cast-iron (electroplated for corrosion protection), chromed castiron, and aluminum. They are available with and without a custom DSE racetested integral reservoir. The pumps are built to flow 3.0 to 3.4 gallons per minute at 1,500 rpm. They offer a special pressure valve for use with a Mustang II rack-and-pinion that lowers the flow to 2 gallons per minute, while keeping proper internal system pressure. Without this fitting, your steering may have too much flow, which can make the steering feel too twitchy and over-driven. DSE also offers custom hard-lines, braided lines, fittings, and pulleys for a perfect fit on your custom application. KRC Power Steering Pumps KRC Power Steering is a racing power-steering products manufacturer. The company took a good look at the TC pump for racing applications in 1996. KRC could not improve upon the TC design to make it suitable for the grueling abuse of dirt and asphalt racecars, so it designed original aluminum and cast-iron power steering pumps to meet the stringent requirements. The lightweight aluminum pump weighs just 3.2 pounds with the pulley. It operates up to 70 degrees cooler than other pumps, and it can save up to 3 hp. It features adjustable flow rates with optional flow valves. The cast-iron KRC pump meets the same durability requirements and has the same flow features, but it’s less expensive. The KRC pumps have the same mounting pattern as the Saginaw TC pump, so they use the same mounting bracket. The KRC pumps are fitted with the necessary AN fittings. KRC pumps require the use of an external steering fluid reservoir. Read more about reservoirs later in this chapter. KRC offers aluminum power steering pump brackets for 289, 302, 351, and 400 engines. If KRC cannot locate the pump in the correct location of your engine, it offers a universal bracket you can cut to custom-fit it. Rack-and-Pinion Steering A rack-and-pinion unit is also known as a “steering rack.” American auto manufacturers have been using rack-and-pinion units in most of their car lines since the 1980s due to the compact, weight-saving design. The aftermarket community saw the performance benefit of the weight-saving, compact design coupled with closer steering ratios, and knew they could be offered as an upgrade for older muscle cars. Flaming River, Revelation Racing Supplies (RRS), Total Control Products, and Wurth-it Designs offer rack-andpinion conversion kits for many 1960 through 1970 shock-tower-equipped cars. These kits work for cars originally equipped with and without power steering. The rack is located in the same location as the original steering linkage (and assist ram on power applications), so oil pan clearance remains almost the same. Flaming River Industries offers a bolt-in rack-and-pinion steering system for 1964 through 1970 Mustangs. It can be installed within hours because it bolts in using original factory holes. The kit replaces the heavy recirculating-ball steering system with a lightweight steering rack. A new steering column and steering shaft is included to further follow the bolt-in features of this kit. They offer a model to be used on 1965 through 1970 Mustangs with Granada spindles. Total Control Products is another well-known company in the market producing rack-and-pinion steering kits. The company offers kits for 1960 through 1965 Falcons, Rancheros, and Comets as well as 1965 through 1970 Mustangs and Cougars. Kits are available in manual and power-assisted models. The kits are designed to bolt in using as many of the factory bolt locations as possible. Trimming the end of the steering column is necessary on the Mustang kits. There is some cutting and welding to slightly notch the frame when installing the Falcon, Ranchero, and Comet steering-rack kit. The reward of responsive steering outweighs the work necessary to install these kits. Flaming River offers this bolt-in, front-mount rack-and-pinion conversion kit for your 1965-1970 Mustang. These racks offer a quicker turning ratio; it’s only three 3 ⁄4 turns from lock to lock. (Photo courtesy Flaming River) Flaming River also offers this bolt-in, rear-mount rack-and-pinion conversion kit, for 1965-1970 Mustangs. These systems are available with or without steering columns, as well as with a variety of different Header Clearance Kits. The Header Clearance Kits help you avoid fitment problems with different header and engine combos. (Photo courtesy Flaming River) RRS offers power and manual rack-and-pinion steering systems for many shock-towerequipped cars. They are well-designed bolt-in kits that install with minimal bumpsteer, if any. They also use factory serviceable tie-rod ends. (Photo courtesy Revelation Racing Supplies) Wurth-It Designs has answered the prayers of 1955-1956 T-Bird and 1954- 1964 full-size Ford owners who want latemodel rack-and-pinion steering systems. The Wurth-It bolt-in systems have little to no bumpsteer and they work with stock or Granada spindles. (Photo courtesy Wurth-It Designs) The RRS rack is a complete bolt-in system that can be fine-tuned to correct bumpsteer. It’s also the only system available with a patented linear tracking design to minimize wear, while decreasing deflection. These design features, combined with 2.88 turns lock-to-lock, combine to give you accurate and durable road reel that is comparable with modern sports cars. The RRS kit also has a low roll center, making it possible to eliminate understeer on most applications, including big-blocks. The steering geometry has a complete camber, arc, and steering axis inclination to suit different applications. The kits are available for 1965 through 1970 Mustangs; 1967 through 1970 Cougars; 1962 through 1970 Fairlanes; and 1966 through 1970 Torinos, Rancheros, Falcons, Comets, Montegos, and Cyclones. Wurth-it Designs offers bolt-in rack-and-pinion kits designed with allaround driving in mind. Kits are offered for 1954 through 1964 full-size cars, wagons, and Galaxies, as well as 1955 through 1960 Thunderbirds. Wurth-it’s rack-and-pinion is a true bolt-in kit; it requires no welding or cutting of the stock frame. It doesn’t hang down under the crossmember, so it’s not a clearance hazard and it doesn’t suffer from bumpsteer problems. You can use it with stock spindles or with Granada upgrade spindles. This kit allows you to get rid of your sluggish and bulky stock steering system and the leaky steering ram. It updates your car to modern-day steering feel with 3.5 turns lock-to-lock. The kit will fit any engine with a front-sump oil pan. What if you want to use headers on your engine? Wurth-it worked with FPA to build some high-quality headers that will clear the steering rack, Z-bar clutch linkage, frame, and bell housing. Racing Rack-and-Pinion Woodward Machine Corporation and Appleton make rack-and-pinion units for dirt, pavement, and road-racing applications. There is quite a bit of planning and knowledge involved in choosing the right unit for your application. When you get the parts, there’s some design and fabrication that needs to be done to correctly mount the rack to your frame and suspension system. There are over 20 different styles of Woodward racks. For help picking the correct rack for your application and installation information, contact either of these manufacturers. You would find a Woodward or Appleton rack used on an extreme Restomod with fully fabricated suspension, such as the suspension shown in the first photo in this chapter. As seen in that image, a ton of fabrication is required to install it. A bolt-in steering rack was not an option. Remote Power Steering Reservoir When running a Saginaw TC pump, it’s possible to use a stock plastic latemodel-style baffled local or remote reservoir. Remote reservoirs give more options for mounting the pump, since you don’t need to mount the pump in a specific position. There are good and bad remote reservoirs on the market, so it is important to be aware of the differences. The return line and the feed need to be placed in proper locations. If the return line is too close to top of the reservoir, the fluid will act as a vacuum and pull air in. This is called aerating. The aerated fluid can cause damage to the steering components. The symptoms will be groaning noises and jerky steering when turning the wheel at low speeds. The return line should be located at the bottom or at least 11 ⁄2 inches below the surface of the fluid. Woodward Steering and Appleton both make racing power-steering racks. With the right knowledge of steering geometry and moderate fabrication skills, these racks can be adapted to just about anything. They are typically found on racecars and Extreme Restomods. All power-steering reservoir tanks are not created equal. The cheap circle-track tank on the right is not fit for street use. The inlet is up too high. The KSE tank on the left has a superior design. If the inlet on your power-steering reservoir tank is too high, it can cause the power steering fluid to aerate. Air in the steering fluid causes loud groaning and erratic steering-box operation. Power Steering Hose There are high- and low-pressure hoses in the power steering system. It’s important to use the right power steering hoses in the right places. If you’re running stock power steering accessories and brackets, you can use stock replacement hoses. The stock high- and low-pressure hoses will be made to the right lengths and have the correct pressure ratings. If you’re using aftermarket hose on your stock steering system or a custom installation, you’ll probably need custom hoses. Whether you’re building your hoses, or someone else is doing it for you, make sure they are using the proper hose and fittings for the job. The pressure spikes on the high-pressure side are too much for standard stainless-steel hose and standard anodized aluminum fittings. Using them for custom powersteering hoses is a common mistake, especially on the high-pressure side. A common mistake in building custom power-steering hoses is using standard steelbraided rubber hose and aluminum fittings on the high-pressure side of the system. Pressures there can reach 1,350 lbs. This hose is only good for a fraction of that pressure. The proper power steering fittings are high-pressure steel, and the hose should be specifically made for a maximum operating pressure of 1,750 psi. A performance power steering system can operate upwards of 1,350 psi, but there are spikes in pressure during operation. There are many high-performance hose and fitting companies, like XRP Inc. They offer power steering hose made of elastomeric tube, polyester inner braid, single wire braid reinforcement, and a polyester braid cover. They also offer a full line of steel fittings and hose ends to make just about any power steering hose for your Restomod machine. Power Steering Coolers Power steering systems can generate plenty of heat, even on the street. While on the track, the temperatures can soar to over 250 degrees. The heat sources are abundant under the hood. In most cases, the power-steering box is close to the headers, which can reach over 1,000 degrees. There are ways to cool down the fluid. People have noted a 30-degree drop in steering system fluid with the addition of a remote reservoir. The addition of an inline power-steering cooler is another way to cool the system. There are right and wrong ways to install an inline cooler. Don’t install a cooler in the high-pressure side; it puts too much stress on the cooler. Plus, if the cooler were to get nicked by a rock, there would be 1,300 pounds of pressure pushing fluid out of the system really fast. Just about any lubricating fluid in contact with hot exhaust is a bad idea. Put the cooler on the low-pressure return side of the system between the power steering box or rack and the reservoir. Coolers can be stacked-plate, extruded-cylinder, or round-tube designs. A stacked-plate cooler is made up of many flat plates (tubes) stacked on top of each other, which looks much like a miniature engine coolant radiator. The extruded aluminum cooler comes in many different forms. They are made of extruded, finned aluminum and are typically at least 8 inches in length with a fitting on both ends. The round-tube cooler is basically a round tube in a straight line, or Ushaped with small cooling fins to help disperse heat. Each design has proven effective in street and track conditions. Be sure the cooler is designed for at least 60 psi and high-heat conditions. A cooler with a 3 ⁄8-inch or -6 AN inlet and outlet is best suited for power steering applications. If it’s a tube-style cooler, make sure the fittings are not soldered to the tube. The solder will melt and you will have a mess on your hands. Top racecars run Setrab coolers. If they can endure competition racing conditions, they can work well on a Restomod. Setrab offers stacked-plate coolers like this one in different sizes. The close-up on the right shows the cooling fins. (Photos courtesy Setrab) This is an extruded aluminum powersteering cooler. Detroit Speed & Engineering offers these to mount between the outlet of the power-steering box and the return port on the steering fluid reservoir. Mount it where air will move around it, but make sure road debris won’t rip it off. Size matters, too. A small 8x4x2-inch stacked plate or 6-inch round-tube cooler will be more than adequate for most Restomods, even on a road course. Anything larger, and the cooling efficiency of the system will be hampered. Some production cars and trucks have been equipped with little in-line coolers. Installing one of these little coolers can reduce the fluid temperature by 30 degrees. The cooler fluid temperature will increase the life of the fluid, the pump, and steering assembly. As with any cooler, if it’s not placed where moving air can come into contact with the fins, it will be less effective. Place the cooler in a safe place where a rock off the tire or debris from an unplanned off-track excursion won’t cause damage to any part of the system. The factory usually places its powersteering coolers on the frame rail in the engine compartment. Unlike with radiators, some moving air for the power steering cooler is better than none at all. Placing the cooler in front of the radiator where cool air is flowing is not always convenient. These sequence photos show a fairly simple bracket bent up to mount the Setrab cooler to the front of a Chevy Camaro. This cooler could be used for power steering, engine oil, and transmission fluid. For some reason, most people typically mount coolers to the radiator, where it can put undue stress on the radiator core. This cooler is mounted between top and bottom brackets made out of aluminum. I used light-tack masking tape to protect the paint surfaces and hold the brackets in place during installation and fabrication. Here is the same Setrab cooler viewed from the front of the car. It gets more than enough air flowing through it. This idea can be applied to any car. Shelby Cobras have been taking advantage of this for decades. The aluminum brackets were hardanodized for protection against the elements since this is a street-driven car. This tie-rod adjuster is offered by Detroit Speed & Engineering. It’s made of 4140 1-inch hex stock, and it is much stronger than the stock unit. The hex allows for easy adjustment over stock adjustment sleeves. The stock sleeve adjusters are flexible sheetmetal. When they flex or bend, your suspension geometry and alignment changes. Why spend good money on aligning your car and not fully utilize the settings? Tie-Rod Adjustment Sleeves Tie-rod adjustment sleeves are a weak link, but they are often overlooked as an upgrade. The stock adjusters are just sheetmetal formed into tubes. They flex under hard driving conditions, which causes variances in suspension geometry. The stock adjusters can also bend, causing the front suspension to be out of alignment. The stock adjustment clamps also make aligning a tough job at the track. A couple of aftermarket companies offer beefy tie-rod adjusters. They’re stronger than stock sleeves because they completely wrap around the tie rods and have full thread engagement. Their strength maintains more accurate alignment and suspension geometry under hard driving conditions. Hard driving conditions don’t just happen on the track. The street is full of potholes, train tracks, and debris that can knock the suspension out of alignment. All performance-driven cars should upgrade to these adjusters. Adjusting the aftermarket sleeves is much easier for last-minute track adjustments and alignments at your local shop, because the adjustment sleeves and nuts can be turned with common wrenches. Written by Tony Huntimer
  4. SPArKy_Dave

    Long Term Engine Storage

    Buy some Soft-Seal from your local industrial suppliers, or even Repco/Bursons may stock it? The stuff I bought, is made by CRC. It's basically a non-drying wax/grease substance, in a spray can - designed specifically for rust protection, of metal machinery parts in storage.
  5. Please excuse the fragmented nature, of the below info... I progressively update this post with copy/paste info, as I find it across the net. (latest update - 09/03/20) _____________________________________________________________________________________________________ https://www.hemiperformance.com.au/shop/shop-by-category/transmission/manual-4-speed.html XB, all models including GT with 2v heads had the BW 0503-003. XC/XD 4.1/4.9 had the BW 0503-009 XC/XD 5.8 0503-008. 003 is 1st 2.82, 2nd 1.84, 3rd 1.32, 4th 1.00 009 is 1st 3.06, 2nd 1.84, 3rd 1.32, 4th 1.00 008 is 1st 2.46, 2nd 1.78, 3rd 1.27, 4th 1.00 Ford never published the codes for XE and XF but the 1st gear ratios are XE 6 cyl. carb 3.43 XE efi & 302 3.06 XE 351 2.46 XF efi 3.40 XF carb 3.50 Other numbers XB Single Rail - 74DA-7003-AB 0503 006 3192 0503-006-3013 XD Single Rail? 78DA-7003-CB 0503-014 (8096) 76 DA 7003 AA 05 03 009 84 DA 7003 BA 0503 038 xd/e/f 0503 carby 1st-3.43 2nd-1.99 3rd-1.43 4th-1.00 rev-3.29 0503 efi 1st-3.50 2nd-1.99 3rd-1.32 4th-1.00 rev-3.47 0506 1st-3.47 2nd-1.96 3rd-1.26 4th-1.00 rev-3.37 0507 5spe 1st-3.47 2nd-1.96 3rd-1.26 4th-1.00 5th-0.79 rev-3.37 xa/b/c 0503-009 (4.1/4.9) 1st-3.06 2nd-1.84 3rd-1.32 4th-1.00 0503-008 (5.8) 1st-2.46 2nd-1.78 3rd-1.27 4th-1.00 A 250 or 302 single rail is rated to 285lb/ft, similar to a stock T5. A 351 single rail is rated to 325lb/ft which is the same as a Z-type T5. A std. wide ratio Toploader is rated at 375lb/ft and a bull nose 425lb/ft. BW single rail differences. All have same mounting flange, which is the same as the 3 speed box except for one bolt. Valiant has longer, finer input shaft, same output I think. Valiant has a short shifter shaft with a dogleg intermediate rod to clear the Valiant crossmember. Valiant has 2.84 first gear, so does cortina. Cortina has foward mounted shifter and short shift shaft with no intermediate shaft, extension housing is different to cater for this. Falcons all have rear mounted shifter and long shift shaft with no intermediate shaft. There are several ratio sets in falcons, from 2.54 first gear fitted to 351s, to 3.47 on xf type sixes. The highest torque rated box is the 351 at around 350lbsft. BW single rail. Valiant has 23 spline input shaft which is longer than the Falcon/Cortina box Valiant has different extension housing with different mounting and shifter to Ford types. P76 single rail is very similar to Valiant type, not seen many so couldnt say exactly what the differences are, if any. Repair kits should be the same, but you'd need to be a bit carefull when its comes to extension housing output shaft seal. As far as I know all Valiants had same 2.84 first gear ratio gearset. Falcons and Cortinas have quite a few gearsets, I know of:- 2.54 first gear (for 351s) also highest torque handing because of larger input gear. 2.84 first gear seen in Cortina six 3.06 first gear in 302s and sixs untill xe 3.54 first gear in later sixes. One extension housing in Falcon with cooresponding shifter position. One extension housing in Cortinas with cooresponding shifter position. This is what I was able to find off the net, and from books in the local library, for the 0503 :- Falcon XA & Leyland P76 2.78/1.93/1.36/1.00 Falcon XB & Charger E48 2.82/1.84/1.32/1.00 Falcon XC/XD/XE 3.06/1.84/1.32/1.00 Valiant VJ-CM 3.32/2.00/1.43/1.00 Falcon XE (4.1 carb only) 3.43/1.99/1.43/1.00 However, Ford used a 10-spline 1&1/16th" input shaft, but Chrysler and Leyland used a 23-spline 1&1/32nd" input shaft. Other XE Falcons got the "new" 0506 4-speed, or it's relative the 0507 5-speed. Single rails came in 4 variations depending what engine they were designed to be fitted behind. All are physically identical on the outside and are interchangable. To check which type you have, look at the small tag on the side of the box. 74DA 7003 A (up to 11/74) 74DA 7003 AB (11/74 onwards) 0503-006 (3.3/4.1) 0503-003 (4.9) 0503-009 (4.9) 1st-3.06 2nd-1.84 3rd-1.32 4th-1.00 74DA 7003 BA 0503-008 (5.8 inc GT) 1st-2.46 2nd-1.78 3rd-1.27 4th-1.00
  6. SPArKy_Dave

    Crankshaft Inspection and Machining 101

    Inspecting crankshafts October 17, 2012 • by Mike Mavrigian After the used crankshaft has been cleaned, the very first check should be for cracks. Here a crank is passed through a magnetic field on a particle inspection station. Regardless of which crank you choose to use during a customer’s engine rebuild or fresh build (used OE or new aftermarket), take the time to inspect the crankshaft. In the case of a new crankshaft, check for dimensions and runout. With a previously used crankshaft, you’ll also need to check for flaws (cracks). Inspecting the crankshaft before installation verifies its condition and allows you to avoid problems and/or comebacks. First and foremost, especially when dealing with a used crankshaft, clean the crank thoroughly, preferably in a jet wash or hot tank. Once clean, always inspect the crankshaft for flaws/cracks. This is best done on a magnetic particle inspection station (commonly known as a magnaflux machine (even though “Magnaflux” is actually a brand name, other equipment makers, such as DCM, for example, make magnetic particle inspection equipment). The crank is mounted horizontally on the inspection bench and passes through a large diameter circular magnet and inspected with an ultraviolet (“black”) light. Any cracks are easily found, visible as whitish lines. If a crank is cracked, don’t even debate the issue — sell it as scrap metal and buy a new one. By crack-checking first, you’ll avoid wasting time by performing further dimensional inspection. Next, check crankshaft runout. With the crankshaft mounted level on a pair of level V-blocks (resting on the front and rear main journals), set up a dial indicator at the center main journal, placing the indicator probe slightly offset to avoid hitting the journal’s oil feed hole. Preload the indicator by about 0.050-inch and then zero the dial. Once a magnetic field has been obtained, an ultraviolet light is used to inspect for cracks. Slowly rotate the crankshaft while observing the gauge. Record your reading. For example, the maximum OE-spec for allowable runout may be listed as 0.000118-inch. If the indicator gauge doesn’t read in the hundredths of a thousandth of an inch, you’ll be hard-pressed to actually determine that tiny number. Generally speaking, if the crank shows less than 0.001-inch runout, it’s probably fine. If the crank shows more than 0.001-inch runout, it needs to be either straightened or replaced. Crank straightening is a precision task that should only be handled by a skilled specialist. Not all cranks can be successfully straightened, by the way. Using a micrometer, measure the main journal diameter (at the center of the journal) of each of the main journals. Record your measurement and compare this to the specifications for that particular engine. Published specs will include a tolerance range (max/min), usually of about 0.001-inch (for example, 2.558- to 2.559-inch). Bear in mind that, if using a reconditioned crankshaft, the main journals may have been re-ground to a smaller diameter in order to maintain serviceability (for example, the mains may have been ground –0.010-inch undersized). [PAGEBREAK] Also measure each main journal for taper (measure the journal area at two locations, toward the front of the journal and toward the rear of the journal). Maximum allowable journal taper is generally about 0.0004-inch. Also, be sure to measure each main journal at several radial locations to check for journal out-of-round. Maximum allowable out-of-round is usually around 0.000118-inch or so (check the make/model engine specs). If the crank passes the crack-check, next inspect for runout. Here a crank rests on a stand that allows rotation. A dial indicator is set up at the center main journal and the crank is slowly rotated to inspect for runout. Next, measure each rod journal diameter at several radial locations on each rod journal. The tolerance range (min/max) will generally be around 0.0008-inch or so (for example, rod journal diameter might be listed at 2.0991 – 2.0999-inch). Measure each rod journal for taper (at each end of the journal surface). Maximum allowable rod journal taper is generally around 0.0002-inch. Also measure rod journal width (base of fillet to base of fillet — in other words, the front of the journal and the rear of the journal relative to crank length), and compare this to the listed spec. If journal width is too tight, you’ll have insufficient connecting rod sideplay. If any beyond-tolerance areas are found in terms of journal diameter, taper, width or out of round, this can be corrected by re-grinding on a dedicated crankshaft grinding machine. In order to correct journals, you’ll end up moving to an undersize (smaller diameter than original), in which case you can easily purchase a set of undersized-I.D. main and/or rod bearings (bearing pairs with a smaller I.D. and thicker walls). Whether the crank is new OE, reconditioned, used, or new aftermarket, measure each main and rod journal diameter with a micrometer and compare your readings with specifications. In order to check crank endplay, you’ll need to temporarily install the crank to the block. Install upper main bearings dry (block saddle and the rear of the bearing must be dry). Once the bearing has been installed, then apply a lubricant to the exposed bearing surface using oil or assembly lube. Just remember that bearing size needs to be uniform — if one main journal must be re-ground to then accept an undersize main bearing, then all of the main journals should be ground to that same size. The same holds true for rod bearings. If even only one rod journal needs to be undersized, then all rod journals need to be ground to the same diameter. Always check with your bearing supplier to first find out what undersize bearings are available (-0.0005-inch, –0.005-inch, –0.010-inch, –0.020-inch, etc.). This will determine the diameter of the re-grind. [PAGEBREAK] In order to check crank endplay, you’ll need to temporarily install the crank to the block. Install upper main bearings dry (block saddle and the rear of the bearing must be dry). Once the bearing has been installed, then apply a lubricant to the exposed bearing surface using oil or assembly lube. If a used crank checks out OK and you intend to re-use it (with no need to re-grind), each journal can be polished on a crankshaft belt polisher, using 400 grit, stepped up to 600 grit. Small surface scratches can also usually be eliminated by polishing. NOTE: Different equipment makers may specify different grit-grade abrasives for polishing. The journals should not be “mirror” polished, since microscopic scratches are needed to provide oil cling. Buying a replacement crankshaft Your customers have several choices when purchasing a crankshaft, including a new OE crank, a reconditioned OE crank or an aftermarket crank. OE crankshafts are available in the original stroke dimension, while aftermarket performance cranks are offered in a range of strokes from the OE spec through increments of longer strokes. Quality aftermarket crankshaft makers include Scat, eagle, Lunati, Crower, Ohio Crankshaft and others. Depending on the application/design, some journal oil holes may feature an extended chamfer to promote oil transfer. General tips 1. If the journal surfaces are damaged (scratched, scored, gouged, burnt), further inspection is required. If the scratches are light enough, the journals may be saved simply by re-polishing with 400 grit, followed by 600 grit abrasive paper. This should be done on a dedicated crankshaft polishing stand, where the crank rotates at a slow speed while an arm-mounted abrasive belt is lowered onto the journal. If the surface damage cannot be eliminated by polishing, the journals mayneed to be re-ground with an abrasive stone wheel on a crankshaft grinder. The installed bearings do not actually provide a uniform round inner diameter surface. The bearing shells feature a slight taper (thinner near the parting line and thicker at top and bottom). This promotes a “squeeze” ramp for the engine oil, allowing the oil to provide the needed support film to support the journal. 2. If a crankshaft’s mains, rods or both are re-ground to an undersize, the crankshaft MUST be labeled to easily identify any undersizing by stamping or etching the undersize on the forward face of the front counterweight. For example, if the main journals are fine but the rod journals are re-ground to, say, 0.010-inch undersize, the stamping or etching should say “ROD 010,” OR “R –10”, etc., to clearly identify the rod journals as having been undersized by 0.010-inch. A negative symbol (-) preceding the number makes it clear that the re-grind factor of 0.010-inch has been removed. Main (and rod) bearings feature a slight bit of extension when installed (where the bearings ends protrude slightly beyond the parting line). This provides the proper bearing “crush” to achieve bearing retention and the proper inside diameter profile for correct oil clearance and lubrication delivery. 3. Also make sure to inspect all fillets (the shoulder area where the journal surface blends into the counterweight or throw area). A journal should never be ground to create a sharp corner, since this can lead to an eventual stress riser, which can result in crank failure. [PAGEBREAK] 4. Inspect all threaded holes (the center hole in the front snout and the flywheel holes in the rear flange). Make sure that the threads are clean and are not damaged. A chaser tap (as opposed to a cutting tap) can clean these threads without cutting and removing too much thread material. 5. Inspect all main and rod journal oil feed holes to make sure that they’re drilled through, and that they’re not plugged up with debris. As a journal rotates, an oil film “wedge” is created, which centers the journal within the bearing I.D. during engine operation. This oil film provides the support for the crankshaft, so that the journals do not actually contact the bearing surfaces as the crankshaft rotates. 6. As far as crank oil holes are concerned, simply deburr the holes to break off any sharp edges. It was commonplace for years for builders to radius-sweep the holes, but you get too much bleed-off doing that, so it’s better to simply deburr the holes, removing as little material as possible. A note about undersize grinding If a crankshaft (rod and/or main journals) is to be re-ground to an undersize, this is done on a dedicated crankshaft grinder, using specific-width abrasive stone wheels. When main journals are ground, the crankshaft is mounted and rotated “straight” with zero runout. When rod journals are ground, since they are offset from the crank centerline, the crank is adjusted on the machine to run at an offset, with the rod journals positioned at zero. Cooling fluid is applied during grinding to cool and clean the journal surfaces. As far as crank service life is concerned, if a crank’s rod or main journals need to be re-ground, say – 0.020-inch, you’ll lose the initial surface hardness. While some builders (or customers) may assume that the crank is no longer usable simply because the surface hardness has been lost, in reality this isn’t a problem. Simply send the crank out for nitriding after the corrective grinding has been accomplished. General clearance recommendations Start with 0.0010-inch of clearance per inch of journal diameter. For example: 2.100-inch journal diameter X 0.0010 = 0.0021-inch clearance. For high performance applications, add 0.0005-inch. If, for example, initial clearance is determined to be 0.0021-inch, add 0.0005-inch for a final clearance of 0.0026-inch. From this point, tighten clearance as your experience dictates in specific applications. NOTE: Use of a dial bore gauge is always the recommended method of measuring oil clearance. Instead of measuring journal diameter and then measuring installed bearing diameter, zero the bore gauge at the actual journal diameter. When you measure bearing diameter, you’ll obtain a direct clearance reading without the need to perform math procedures, avoiding potential math mistakes. If clearance modification is needed, do not increase or decrease clearance by modifying housing size outside of tolerance limits. An undersize housing will over-crush the bearing; and an oversize housing will reduce crush and bearing retention. Once the main caps have been installed, follow the specs for torque value (or torque-plus-angle for OE fasteners). Tighten all primary (vertical) main cap fasteners first, in stages and in proper sequence, then tighten main cap side bolts if applicable. Today’s leading bearing manufacturers utilize finite element analysis computer modeling to examine the elastic deflections of all bearing-related areas. EHL, or Elasto-Hydrodynamic Lubrication, allows engineers to more accurately determine the effects of dynamic forces in relation to forces and oil clearances. This understanding of loads, metal deflection and effects on clearance has allowed a more precise view of what the bearings are subjected to, and furthers engineers’ ability to develop bearings that will function properly in high-stress dynamic racing applications. [PAGEBREAK] If you really want to get nit-picky with regard to bearings, pay attention to not only suggested clearance, but also take into account the bearing surface are from an anticipated load standpoint, as well as bearing speed, based on journal circumference. Once the main cap fasteners have been tightened to specification, the crank may be rotated. Check for free rotation. If a bind exists, re-check bearings clearances, main bore alignment and/or crank runout. If the crank rotates freely, then set up a dial indicator to check for crank endplay. Using a flat-blade screwdriver (prying between a counterweight and main cap), carefully move the crankshaft fully rearward. Adjust the dial indicator with about 0.050-in. of preload, then zero the indicator gauge. Using the screwdriver, pry the crankshaft fully forward and note the amount of movement on the indicator. Perform this step several times to verify your results. Compare the measured endplay/thrust movement with the OE specifications. In higher end engines, where you plan to run smaller journals sizes, you really need to pay attention to the load carrying capabilities. In order to provide adequate oil delivery, some high-end race engine builders sometimes drill extra oil holes in the bearings and partial-radius grooves in the housing or saddlearea of the mains to create multiple oil supply points. This is especially important in engines that use smaller bearings and will experience higher loads (don’t try this at home). As far as bearing clearances are concerned, for street engines that see higher loads, some builders tend to run somewhere around 0.003-inch for mains and around 0.0025-inch for rods. For engines that will see lots of heat for extended periods, such as endurance engines or marine engines, tighter bearing clearances are the norm, to compensate for the fact that clearances will loosen under hot conditions. If the crankshaft features a reluctor wheel (also called a tone wheel) for crankshaft timing position, it is possible that you’ll need to either replace a damaged wheel or install a wheel to a new crankshaft. This must be done with a dedicated locating tool in order to achieve the correct clock position of the tone wheel. Shown here is Goodson’s reluctor wheel positioning and installing tool. In a high-speed, high-load engine application, experienced builders tend to run a fairly high crush (where bearing shells mate together), while maintaining this within an acceptable range. Considering bearing load and journal and housing deflection, you want to make sure that the bearing is securely held in place. Where you have oil films that are in the tenths of thousands clearance, the bearing gets very hot. If you don’t have adequate crush, you won’t get enough heat transfer. Avoid taking housings to their maximum size, to avoid inadequate heat transfer. Crankshaft main and rod journals are machined to size (diameter and width) on a dedicated crankshaft grinding machine. Abrasive stone wheels rotate against the rotating crank while lubricated by the machine’s coolant supply. The main journals are ground with the crank set-up to rotate at its main centerline. Connecting rod journals are ground with the crankshaft offset-positioned to rotate on the rod journal centerline. When a builder opts for smaller journal diameter crankshafts (to reduce mass) they sometimes modify the crankshaft journal oil holes in order to drive more oil to the rods. As you shrink the rod journal diameter, the load goes up. In order to get extra oil to the rod bearings, they create a slight teardrop groove to the crank main oil holes. The leading edge (attack side) of the oil hole is slightly grooved. As the crankshaft rotates, this slight teardrop-shaped cavity fills with oil and is then force-pumped into the oil hole, increasing boost pressure. This can cure problems with rod bearings that were otherwise seeing too much load. This can be done with a grinder, but is best performed on a CNC machine. However, you need to pay strict attention to the dimensions of the teardrop groove, in terms of width, length and depth. Generally speaking, this teardrop groove is usually around 0.300-inch to 0.400-inch in length. If the groove is too aggressive, you could start starving the mains for oil. The specific profile of this groove controls the amount of oil pressurizing into the rod. Again, this is nothing for the weekend builder to mess with, and is certainly not necessary for street applications. ●
  7. SPArKy_Dave

    Micrometer Tech

    By Lyle Haley on Mar 1, 2019 Tenths Are Not For Camping I was told a few times that “tenths are for camping” when I was “chasing tenths” in my early machining career. We had micrometers with “tenths” reading on their spindles but the tolerances we had for our “vintage” engines allowed us to be fairly sloppy and still produce what was considered a quality product. Keep in mind though; this was the era when we all walked the 5 miles to school uphill both ways. There is a big difference in newer engines – today, we can expect engine life of 300,000 miles or more. Early failures in most modern engines can probably be avoided with good maintenance practices. But working on a precisely built modern engine requires measuring in “tenths” as mandatory. Since measuring in tenths is now a way of life, let’s take a look at your measuring equipment. You must consider that even with the best of care, micrometers, dial indicators, etc. can wear and become inaccurate. Just occasionally checking your outside micrometers with the reference standard that comes with them is not nearly enough to ensure the accuracy you need. Whether you are using a micrometer for setting dial bore gauges, inside micrometers or snap gauges, you are relying on the micrometer’s accuracy for the size. For example, when you use an outside micrometer to set a dial bore gauge, the bore gauge is used as a “comparator” to establish a tolerance. The exception to this is when some type of calibrated setting fixture is used instead of a micrometer to set a bore gauge. Since outside micrometers are usually what most shops rely on for an accurate dimension, let’s focus on their use and care. Regardless of the brand or type of micrometers you have, how often do you check them for accuracy with the reference standards that are usually supplied with them? Keep in mind that using your supplied standards is not considered “calibrating” your micrometer. You are just confirming that, by using the standard made for it, the micrometer is accurate at that size. How accurate it is for the rest of the one-inch travel of the barrel should be confirmed by using gauge blocks. There are lots of published technical papers out there telling you how critical your calibration procedures are. One of my favorites is a paper titled “Calibration Guidelines for Micrometers Using a Five-Point Calibration Method.” Under these guidelines a micrometer that is sent to a qualified calibration lab is first checked for obvious damage and that the barrel runs the full length freely. The condition of the spindle and anvil faces are checked, and any wear of the threads in the barrel is recorded. To check for thread and barrel wear, traceable gauge blocks are used to measure five different sizes. An example of the micrometer being checked with gauge blocks would be a -0.997˝, +0.611˝, 0.502˝, 0.246˝ and 0.128˝. The different sizes mean that the barrel of the micrometer will be stopped in a different position for each measurement. Any error more than +/- 0.00005˝ would show there is wear on the internal threads of the micrometer. These are not the only dimensions used for calibrating micrometers – most any combination will work as long as you are certain they are accurate and consistent. Gauge blocks must have a certificate of traceability from the National Institute of Standards and Technology (NIST). This means that they can be used to meet the 4:1 rule of calibration, the common rule of thumb first published in 1960. Gauge blocks are considered the highest in the hierarchy of precision – the accuracy of a gauge block is typically +/- 0.000002˝ and the accuracy of a micrometer is typically +/-0.0003˝. This difference exceeds the 4:1 ratio. The other area to be checked is the flatness and parallelism of the face of micrometers. You’ll never even notice it by looking but wear on the face of a micrometer from normal use can cause the face not to be flat. Physical damage, like dropping a micrometer, can cause the faces not to be parallel. Accurately checking the flatness and parallelism is done using an optical flat or optical parallel and a monochromatic light. The optical flat is a specially ground piece of glass that shows errors by using light bars reflecting off the faces of the micrometer. This picture shows a micrometer face being measured with an optical flat using a monochromatic light source. The space between the light bars is approximately 12 millionths of an inch. The straightness of the lines indicates that the surface is virtually flat. A simpler way for checking flatness is to use a ball or the sphere from a CNC probe. Accuracy matters – the heat from your hands can cause the metal sphere to grow enough that it will give erroneous readings. I have had success determining if a micrometer face is flat by using a tenth reading dial bore gauge. Carefully moving the contact point around the micrometer faces can show if it is dished out from normal wear. Even companies that have a dedicated gauge department will usually have an outside lab periodically certify their instruments. The cost of traceable gauge blocks, optical flats, the monochromatic lighting and a temperature-controlled room can be significant. But when you add the training and competence of people doing the checking you can see that it takes a very large company to justify a complete in-house lab. How a shop keeps track of the condition of their measuring equipment depends on many factors, and paying attention to the accuracy of your equipment is paramount to producing a quality product. However, when you add in the human element to doing precision measuring, you should realize you have another variable to work with. An outside micrometer can be used very accurately to get a dimension, but it can also be used as a crutch to confirm a dimension the machinist wants to see. Not only do you need to check the accuracy of the micrometer but that of the user as well. One method of checking the accuracy of employees using micrometers is to put a piece of tape over the dimension of a gauge block, then have everyone who uses micrometers measure the gauge block and record what they see for size. Once again, care must be used when doing this as just the heat from handling a gauge block can change its dimension. To be more practical, in an average shop you could use a freshly ground and polished crankshaft for checking. When outside micrometers are calibrated by labs they use the spring-loaded ratchet on the micrometer to get equal pressure on the part. Whether I am right or wrong I have a problem measuring a round surface like a crank journal using a ratchet on the micrometer. Establishing the “feel” of the micrometer passing over a journal is critical to getting a consistent, accurate measurement. However you do it, getting all micrometer operators to not only understand the importance of consistency but also the importance of understanding the consistency of size can be an obvious benefit for producing a consistent product.
  8. Minimizing spark scatter in the Vintage race engine by admin | Jul 29, 2015 | News, Top Stories | 0 comments By Sam Logan Photography by Moore Good Ink & V&B Engines Often Vintage racing engines exhibit excessive spark scatter caused by torsional vibration in the distributor drive system. To correct it Virkler & Bartlett adds a miniature flywheel to the system. They mold a series of rubber couplers with a range of Shore A hardness, which allows them to tune the system. Note rubber coupler glued within steel ring. How to get the best from a Vintage engine ignition system Aided by the latest King 16-T distributor machine Virkler & Bartlett check the distributor’s performance, its parts, including bearings and point’s cam, as well as coil, condenser and plug wires. Particularly useful for complex Vintage engines with two distributors and four sets of points, its advanced technology not only allows them to analyze and tune the ignition system but also to break-in all the ignition components on the machine rather than on the engine. Chatham, Virginia: Vintage racers are often forced to live with points-and-coil ignition. But the most successful know the shortcomings of the ignition system and have it corrected. For the past forty years or so electronic ignition has been the standard, but most Historic race cars produced before the 1970s are equipped with something other. Unfailingly, coil-and-points ignition systems work best when optimized mechanically and electrically. But how is it achieved? Vintage racers seem to run a little faster each year, and as compression ratios and engine speeds creep up, deficiencies in points-and-coil ignition systems can precipitate the perfect storm of performance problems. Bob Bartlett verifies spark advance for each cylinder and adjusts advance curves. Today’s Vintage engines are often run at higher RPM and power levels, putting additional demands on the points-and-coil ignition systems. Background Just over one hundred years ago, the brilliant engineer Charles Kettering invented the ubiquitous battery-powered “points-and-coil” ignition system that first appeared on the 1910 Cadillac. Remarkably, it was used in most cars until the mid-1970s. An engine-driven mechanical cam operated a set of breaker points, switching electrical current to the coil which converted it to high voltage required to fire spark plugs. A rotor within the distributor routed high-voltage impulses to the correct spark plug. The condenser had the dual function of extending the life of the points by quenching the arc across the points and forming a resonant circuit with the coil that boosts peak voltage. Old timers remember tune-up kits consisting of spark plugs, points, rotor, and condenser, which were duly installed at 12,000-mile intervals. Invariably, engine performance deteriorated as tune-up time approached. The eight major elements in the points-and-coil ignition system: Common problems and some of the solutions Race engine builders Virkler & Bartlett have become an authority on point-and-coil ignition. They use a King distributor test machine that allows them to examine and make adjustments to the entire ignition system. Their engine dynamometer includes a video system with timing light, allowing them to observe ignition timing across the range of engine speeds. • Spark Scatter – refers to any random and unwanted variation in ignition timing at a constant engine speed. Mechanical components are examined first. The entire drive system from the crankshaft to the distributor must be sound and the distributor bearings free of play and points unworn. The distributor shaft must be straight and the advance mechanism clean and lubricated. • Advance Curve – Mostly older race engines use a mechanical advance system, which consists of centrifugal weights and springs. V&B check the advance curve with their King distributor machine and adjust if necessary. • Dwell – the number of degrees the points remain closed is critical to ignition system performance. It is a function of the point’s gap and point’s cam design. Sometimes V&B observes misfire or phantom, unwanted ignition events occurring with misadjusted dwell. • Points – The rubbing block of the point’s assembly wears-in after installation and consequently effects dwell. It’s important to examine dwell and re-lubricate the point’s cam after wear-in. V&B executes this on the distributor machine. Further, they discovered it’s best to use Mallory Cam Lube Grease. It’s made for the purpose. • Wires – Even vintage racers use radios, data acquisition systems and other electronic gear. Solid conductor wires are not compatible with electronics, but some of the better RFI suppressed wire will still deliver a hot spark. Keep ignition wires clean; lacquer thinners works well for the purpose. • Condensers – As reliable as bricks in the old days, regrettably, today’s off-the-shelf condensers are prone to failure. As a result V&B supply specialty high-reliability condensers. The symptoms of a bad condenser are reduced life expectancy of contact points, high-speed misfiring, low-speed back firing and missing, increased spark scatter or some combination of the four. Some condenser problems are thermally linked. Sometimes V&B use a heat gun and freezing spray for diagnostic purposes. • Coils – As a general rule, 3-ohm coils work well at lower engine speeds and with fewer cylinders. Low impedance coils of 1.5 ohm or less, shorten point life and require more current, but work better at higher engine speeds, increased compression ratio and more cylinders. Always use a coil designed for points and use a ballast resistor if required. Like the condenser, some coil problems are thermally linked. • Spark Plugs – Avoid exotic metal plugs such as platinum. The humbler metals in standard plugs have lower ionization voltage—meaning it’s easier to set up an arc with them. Don’t use giant spark plug gaps prevalent on today’s new cars; consider 0.025” as a good starting point. Old-time racers would often start and warm-up their cars with a hotter set of plugs to reduce fouling then replace them with a colder set for the race. Finally, electrical arcs like to propagate from sharp corners. So don’t race with an old set of spark plugs with rounded center electrode. Call (434) 432-4409 to speak to V&B’s Bob Bartlett personally
  9. SPArKy_Dave

    NC Fairlane with watery fuel?

    If the Coil is visually cracked, it will likely be no good. If the hall-effect sensor has failed in the closed/power-on position, it can overheat the coil. You can easily test the primary/secondary winding resistance on any coil, using a multi-meter.
  10. SPArKy_Dave

    NC Fairlane with watery fuel?

    Ignition issues are quite often caused by a dodgy hall effect sensor. It can also cause the coil to fail, yeah. You need an oscilloscope to confirm what's actually happening though.
  11. SPArKy_Dave

    Cleveland HEADERS - anyone used these?

    I got factory ceramic coated Pacemaker headers, for my XG some yrs ago. They're pretty fancy looking.
  12. TBH, it should just work, with a key off/on reset, and maybe a battery reset. Also - check your wiring loom where it runs over the Aircon pipe, near the ECU in the engine bay. B-series are known for wearing right through the conduit covering, and damaging the wires. Especially ones with lots of km's/run-time, etc. It happens on the underside where you don't see - friction against the metal pipe.
  13. Going by the fault-codes, it's most likely a wiring issue. Have a close look at the transmission wiring loom, from the engine bay, back to where it plugs into the transmission. It's only a short wiring loom, so will be easy to check. I'd say either the wiring has been damaged, a transmission loom plug is not seated correctly, or one of the plugs has a pin fitment issue.
  14. SPArKy_Dave

    stumped

    You need 1,2,3,4 connected Pin no.5 is not needed. 1 and 2 is the relay coil - energised by the ignition circuit. 3 and 4, is the power from battery, and out to the fuel pump. If you haven't chopped any wiring yet, you can de-pin the plugs without cutting any wires - using a tiny screwdriver or connector de-pin tool. Then push the existing connector pins into the new plastic plug shell.
  15. Some technical info, on sizing turbo's correctly. (credit goes to Garrett Turbochargers) Turbocharger TECH - wheel trim and housing Area/Ratio.
  16. SPArKy_Dave

    stumped

    There may be some pin-out differences, between the EL and ED(XG) ECU. Have you tried re-fitting the original ECU? I would also double check you have the relay plug wired correctly. Sounds like you do, as the fuel pump primes. Start by determining what you're missing - ie, spark, or injector pulse. If the distributor is not sending a pulse to the ECU, it won't energise the injectors.
  17. SPArKy_Dave

    3.9l xg problems

    Check obvious things, like firing order maybe?
  18. SPArKy_Dave

    3.9l xg problems

    The map sensor has an electrical plug, and a vacuum line. I've found the vacuum line/s can sometimes come adrift from the manifold TEE, down low on the end of the log manifold. Did you check there too?
  19. Originally posted by user DEANKDX Copied over from another forum, due to importance. I bought this set http://cgi.ebay.com....rack=true��last August 2011 figuring the main issue would be wear sooner than TRW branded stuff. i did not expect a FAILURE in a part i assumed was one solid cast. seems they are manufactured in 2 parts... and the thin section of the broken part is approx 1mm which surprises me it lasted the 10,000km it did. this failed on a slow intersection turn without warning(approx 15kmh). you could only imagine what could happen if it failed at highway speeds. i'll be changing at minimum the other side one as precaution to a TRW brand which are closer to $50 each(still cheaper than a tow truck let alone a life or injury) THIS DISGUSTS ME TOTALLY, And although i know you get what you pay for.... you shouldn't be able to buy at any cost something so inferior (worn originals would be safer) if you have any suggestions for AUTHORITIES to contact regarding this i'd like to get the word out to prevent this crap from ending up on our roads. i plan to contact vic roads and RACV to pass this on to whoever will listen.
  20. That's why Ford called them CenterFold bench seats! They have extremely comfy fold-down arm/elbow rests. The cushion/arm rest is also a nice handy grip, for when doing your typical x-series one handed steering - whilst going around corners at a brisk pace. I have x5 x-series with bench seat column auto. XF's have the comfiest bench seats, XG's are a bit firm, and XH's are an in-between.
  21. SPArKy_Dave

    3.9l xg problems

    Sounds like the MAP sensor may be un-hooked - lives near the coolant bottle/tank. LPG stalling like that, often means a vacuum leak.
  22. I've always purposely bought column shift Auto x-series utes/panelvans. They are awesome! Column Auto, Bench Seat, Rubber floor mat.
  23. SPArKy_Dave

    FC LTD centrecaps

    I've always liked the LTD factory tinted tail lights. Which tyres did you choose?
  24. SPArKy_Dave

    Panko's Mk1 Escort (Round 2)

    My understanding, is that's correct operation for HEI coils. Coil dwell time is altered to reach the same coil current, no matter the rpm. https://www.autospeed.com/cms/a_113140/article
  25. SPArKy_Dave

    Panko's Mk1 Escort (Round 2)

    The GT40 coil has a primary resistance of about 3.4 ohms so doesn't require a ballast resistor and must get full battery voltage at all times. The GT40R coil has a lower primary resistance of about 1.4 ohms so must be used with a resistor, whether it's a ballast resistor or a factory resistance wire in the wiring harness. Points ignition systems, supply full battery voltage to the coil whilst cranking, and circa 9v to the coil whilst engine is running. This is to account for voltage drop during cranking, so a strong spark is provided, (and to limit current through the points, so they last longer). The resistance wire/ballast resistor, is often 1.6 - 1.8 ohms. The coil positive terminal, may have two wires running to it, through one connector - one supplies straight battery voltage ONLY when cranking, the other supplies 9v through the resistance wire (or ballast resistor), via the ign/run circuit. Electronic ignition conversions shouldn't be too fussed on voltages (12/9v), but the coil must suit the supply voltage configuration - ie, resistor or non-resistor type. However, some conversions, require a HEI coil - which has a very low internal resistance - circa 0.7ohms. Check what coil resistance, your electronic ignition system expects to see. A low resistance (High Energy Ignition) coil, will draw alot more current (circa 20A) so check existing wiring is suitable. My suggestion is (if possible) leave the wiring as is, and confirm the correct GT40R (resistor) coil is fitted, and will work happily with your conversion.  Coil dwell (aka charge time like a capacitor) also plays a big factor in correct operation. Electronic ign with short dwell-time, will not energise non-HEI coils correctly. Examples: GT40R, no ballast resistor… 14V / 1.4 ohms = 10 amps. (will overheat/fail) HEI coil, no ballast resistor… 14V / 0.7 ohms = 20 amps. GT40, no ballast resistor… 14V / 3.4 ohms = 4.1 amps. GT40R with 1.6 ohm ballast resistor… 14V / 3 ohms = 4.6 amps. GT40R with 1.6 ohm ballast resistor... 9V / 3 ohms = 3 amps. GT40 with 1.6 ohm ballast resistor... 14V / 5 ohms = 2.8 amps. (no good/weak spark) GT40 with 1.6 ohm ballast resistor... 9V / 5 ohms = 1.8 amps. (no good/weak spark) Part number Primary Primary Primary Turns Secondary Secondary Secondary Output KV Peak VOLTS Turns Ratio Ballast Short Resistance Inductance Resistance Inductance Turns 50pf/1 Meg Current resistance Order Ohms mH K Ohms Henries @ 100Hz Amps number 9 220 061 100 3.1-3.4 13.8 - 15.2 345 6.8-9.2 56.7 22200 26.3 3.4 12 64.3:1 SU120 9 220 061 308 3.2-3.5 14.0-15.5 345 8.0-10.0 68.8 24500 26.3 3.3 12 71:1 GT40 9 220 061 400 1.45-1.55 6.3-6.7 240 6.8-9.2 50 22200 32 5.24 9 92.5:1 1.5 SU120R 9 220 061 430 1.25-1.35 6.3-6.7 240 8.0-10.0 66.1 24500 29.1 3.7 9 102:1 1.8 GT40R
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