Rebuilding my crossflow

[bigpaulo 239]

ok, im in the planning stage for rebuilding my 300k+ motor.

these are my plans/ideas so far:

 

machine and hone the block

machine and balance the crank

new pistons, (8cc?)

new balancer

get rid of clutch fan and fit thermos

crow cam 14892

shave the head down to achieve 10.1 compression or there abouts?

port and polish the head

bigger valves

roller rockers

heavier valve springs

Aussiespeed 4bbl manifold

holley 465 with vac secondaries

extractors

 

one thing i know absolutely nothing about is ignition. but from things ive read, im thinking run the tfi dizzy off an efi, msd blaster coil, and msd ignition control, either the standard on or the programmable one?

 

anyway, from the information ive gathered, this engine combo should provide me with a fun mild engine that will still be comfortable to drive around the streets on a regular basis. i have no idea what sort of power this will make, but im damn sure it will be better than the 88rwkw ive got going at the moment...

 

Id love to hear your input and opinions on what ive come up with. PLEASE FEEL FREE TO CORRECT ME IF IM WRONG! let me know if ive left anything out or should change anything.

im hoping i can fit this into a 4grand budget...if not, ill just have to work harder!

 

also, if anyone knows any reliable engine builders around melbourne who could do this sort of work, let me know.

 

Cheers!

Paul

 

[bigpaulo 239]

I will no doubt have many more questions to ask, please be patient while im learning! 

[slydog 7,873]

Ask away bro...until you pull yours down you don't know what it has or needs.I have seen cranks with 250,000 that didn't need a polish let alone a grind.Bigger inlets and springs to suit for sure but you need matching rocker gear and valves to suit.But we also need to know what head you have ATM to dictate what pistons and compression.Camshaft is based on drivline,gearing and intended use aswell.So is your auto manual what do you want to achieve...?

 

I like Camtech over Crow but you can use as you wish aslong as the numbers suit you and your needs.Carby could be a 600dp as xflows love carburation and if driven sensibly wouldn't use any more fuel really.I know Jase made his 650vac sec carby run 11's so they can be made work for sure but a dp is just simple to make work and I'm lazy.That said on a mild combo maybe a 500Holley could work well too?Check out the porting thread Seano and the boys smash up and alot of little tips in there show a polish may not be ideal or even needed at all TBH.That said Stumper is the man for your porting needs.

 

The TFI is the go for sure on the xflows but a simple Streetfire CDI box plus a matching coil would do.And some good leads like the ones Q makes as a kit.I know Gerg and others love there adjustable units but it is somthing I cannot add to as I don't use 1 on mine based on it's limited street use.There's a understatement Rob... 

 

Maybe PM Ando76,Pro250 and such to see if they have some stuff to suit your needs or even post up a wanted add so we can try to keep your costs down a bit.But I like the fresh engine,hyd cam and big ignition as a basis.Can't forget extractors and exhaust as a important part of the equation but that can be added later on...

 

Engine builders is something you need to talk to the Vic boys about but getting the work done by someone else will hurt your budget ALOT,but maybe a necessary evil.Again maybe Dave (Pro250) has something he could sell you straight up???   

[bigpaulo 239]

Thats a fantastic response thanks slydog!

The head ive got is a C2. The gearbox is a T5. Diff gears are standard, factory LSD.

I basically want to build an engine with more power, especially a little earlier in the rev range. So maybe im looking for torque? I currently am running a 350 holley on a redline manifold, and i noticed that it picks up nicely as the revs get higher, but not so much boogie in the lower end of the rev range. This is especially noticeable going up hills. Im looking for more throttle response, so that the power is at my foot when i want it, not having to wait until the revs climb before i get any benefit.

That being said, i dont really want to change the diff gears too much as highway driving is quite pleasant at the moment!

The only reason i chose Crow cam is because their website showed a rev range at which the cam operates in. the 14892 cam operates between 1800 and 4800, i figured this would be the best for my situation as i never really rev over 5000 anyway. If theres a better cam company to with im all ears, however i dont understand all the lobe lift and degrees jargon... I also dont want a too lumpy cam. A bit of lope in the idle i would be happy with, but i dont want to sit at the lights while my car shakes itself to pieces...

I highly doubt ill ever use the car for track. Maybe one day at a strip just to see what time I get, but not in competition. I would still like to drive it on the street on a regular basis. That being said, I still want a car that will hold its own against other modified street cars. (cough holdens cough)

The reason i listed a holley 465 is because of its smaller size and the fact it has vacuum secondaries. That way while im putting around the streets it will run econimcally on 2 barrels, but when i stick the boot into it all 4 will open up. But i really have no idea what size carby will suit this engine combo, that was just a guess.

As much as id love to tackle the build myself, i dont have the tools, the space or the know how. And i figured if an engine builder does it and something goes wrong, ill have some sort of guarantee on the build...

I also know nothing about head work ie machining, polishing etc. and wouldnt dare tackle that myself.

 

[gerg 10,871]

The cross flow head is a pretty good unit and has a bit of headroom to work with before it becomes a limitation. Certainly for your application, it's pretty much spot-on without too much modification. Maybe a tidy up of the bowls and short-turn and that's it.

 

Sounds like you need a towing cam or one above that, say a 208/208 @ 0.050" but with no more than 0.500" lift to keep your stock valve train. Stock crossies run out of flow above 0.450" lift anyway. If you're after a really good deal, go with Precision International for all your bits. They sell a cam called "Dynotec" and are very cheap. When compared to a Crow I bought, it looked identical, they even use the same blanks!

 

Compression should be below 9.5 with a mild cam like that. Just a light skim off the head and deck will get you there, depending on what comp you're starting with.

 

You may benefit from a couple of tricks that the V8 crowd like to use, like dividing the barrels between cylinder groups to get better low-end response. In your case, you'd simply put a divider between the two halves of the throat in the manifold, separating 1-2-3 from 4-5-6 evenly. You could fab one out of sheet ally and epoxy it in or get it welded. This in effect turns your setup into two single barrel carbs. Your idle will be sweeter and torque should improve. Also you could put a 2-hole spacer under the carby to straighten out the flow from the barrels into the manifold.

 

The 350 is a well-sized carby for this application. However some old Holden boys at work talk of the old Stromberg WW-2 found on 253s and some 302 Fords and how they felt this was a better carby all round. I used one briefly on my Corty and it went well but went to LPG not long after. Good luck finding one now though.

 

You didn't say what manifold you had, but I'm assuming that it's something like a Redline. These aren't that good for fuel distribution but could be helped along with a but of tickling on the tight corners both on 1 and 6 and into the plenum from the carby. If you really want to get into it, find a single point EA manifold and graft it into the cross-flow port flanges. These are nicely shaped and would make a nice street manifold.

 

Go with 6-2-1 extractors for more space and better torque. 6-3-1s sound nicer though.

 

Yes Slydog is very correct in everything he mentioned, including my love of MSD programmable. It really wakes up any pre-efi engine and in conjunction with a GM map sensor, eliminates all mechanically variable timing, plus has other features like switched retard (say you come across shit fuel) and rev limit, plus a whole lot of other stuff. There are folks on here who know how to make the TFI dizzy talk to them so there's a wealth of info for you.

 

Sorry for crapping on, it's a bit much to take in but we're all sharing whatever knowledge we can. Have fun!

[bigpaulo 239]

All information is good information! The more detail the better!

Id be interested to hear what type of cams you guys are running in your modified motors, and where in the rev range the cam really shunes. Also what your idle is like. I think the cam I choose is going to be the major factor in this build, as thats what will truly change the performance of my engine beyond the bolt ons, ie caby, manifold, extractors.

And yes my current set up is a 350 holley into a redline manifold and extractors. So ive gone as far as I can without opening the engine up. But I will change the manifold to an aussiespeed, as they seem to have the best flow design.

[slydog 7,873]

Prob only benifit if you turn the carb east west...which I would do if I stayed 4 barrel anyway.For what your talking about I think a 2 barrel is better suited TBH and your current Redline would be fine to keep costs down but the Aussiespeed better.

 

Cam choice is something alot of people have different opinions on and it comes down to personal choice...I prefer lift over duration as it add's torque but others like duration.It's about finding the happy medium for you...

 

Compression and camshaft need to go hand in hand and as such I'd suggest talking to actual cam grinders like Camtech,Clive Cams and so on.Your 350 carb can be made to work well and as you want a low reving unit it maybe be better suited TBH.

[bigpaulo 239]

a few questions for you slydog:

lift and duration, is that how far the valve opens and how long it stays open?

also you mentioned more lift adds torque, what does more duration do?

[slydog 7,873]

Yes how far the valve is raised off the seat...duration for how long.

 

Lift=torque duration=HP in simple terms but finding the combination of both to work best for your needs is the tricky part.Seeing as you will most likely be using a closer to stock valve train and not revving it much creates it's own problems in that lift requires stiffer springs and stronger valve train gear but a bigger duration cam means the valve is just open longer,that has it's drawbacks as well.

[gerg 10,871]

If using stock bits, your cam selection may be limited to the first 3 or 4 rows down from the top of the list of specs. They generally start at mild and get wilder from there. Although mine is a 302C, the characteristics would be the same for a crossy, and my specs are 206/214 @ 0.050" (the most important spec for duration) and mine idles like a silly stocker and will go down to 500 rpm if adjusted so.

 

Being a smaller motor than the 351 the cam's designed for, things happen a bit later in the rpm range. Mine starts waking up at about 2500, really gets up at 3500, continues to 5000 and slowly tapers off to my 5500 limit. That said, I can easily pull in 4th from 1000 rpm no sweat. A crossy would do it even easier than that, having a dirty big stroke for more leverage (torque). Would you like an explanation of cam specs? You just might learn something....

[bigpaulo 239]

Explain away Gerg!

This is the kind of stuff they SHOULD teach in schools.

 

Also im quite happy to modify the valve train as required to suit the cam.

[bigpaulo 239]

http://www.crowcams.com.au/media/catalogues/19.0%20XF_all.pdf

 

the 14892 is the one im leaning towards...

The only reason im looking at crow cams is because they have this chart thats simple enough for me to sort of understand!

[slydog 7,873]

Look here...I like the 517 my self as you are running some stuff and will have a bigger ignition.It has more lift but is still safe with stock gear but bolt on roller rockers would be better and some new valves,retainers locks and stuff and a multi angle valve cut.

 

http://www.camtechcams.com.au/ford_6cyl_xflow_hyd.html

 

Q runs the 528 and his car runs the qtr in 14.7 @ 92mph which if we insert perfect world data it should be a 14.2.Q's car is a basic EFI 250 T5 3.23 diff geared full weight XF with everything and it embarrassed a few v8's and held it's own in the street drags @ Heathcoate last year after driving 10hrs both ways.Not many others did that I can tell you...

[bigpaulo 239]

ah nice thanks sly.

that 517 looks pretty good, quite comparable to the crow 14892 except with a wider rpm range...wont say no to that!

[bigpaulo 239]

would that cam require better compression also?

[slydog 7,873]

ah nice thanks sly.

that 517 looks pretty good, quite comparable to the crow 14892 except with a wider rpm range...wont say no to that!

 

Thats because it has some lift.And yes I would like to see it have 10.1 minimum... 

[wagoon 2,429]

Paul, I was looking for pretty much the same as you not so long ago. I broke a major rule of modification: make a list and don't change it. If you change your focus you will pay ALOT more, doesn't mean you will be worst off but you will pay more.

Some cheap extra insurance is these bolt on non adjustable roller rockers which are perfect for a hydraulic cam which you are looking at. They come with a lifetime warranty and are a very nice bit of gear, I had a set until I broke the above underlined rule. Part number SCP-1069BL but you have to order direct from USA as it's for an american V6 but will fit a crossflow, $205US from summit racing.

When I started looking for info on crossflows I had owned several high performance cars but never had undertaken a major rebuild project before. Since talking to people on this forum I have ported this cylinder head which is the same as yours

and I am now working on deburring a cylinder block and modifying oil galleries. People here are more than willing to help, I would have never been in the position I am in today if it were not for this forum. I now own a solid roller cam crossflow that made 347 flywheel horse power and ran 11.5 in a cortina with a previous forum member. Another forum member found a cylinder head for me that cost $200 to buy(it flowed 330HP (209cfm) when I purchased it) I have spent a further $600 on porting the head (the machine shop and machinest was recommended by a forum member) and will flow 230-240cfm. I have had to rebuild this solid roller cam engine(this is the cost for breaking the above rule) but it will end up being an engine from my dreams.

The most important thing I have learnt from the many years of false starts on projects I have had is be honest with how you are going to use the car and be honest on your budget. These 2 things will be the biggest deciding factors on building your car.

Mate best of luck building your car and never be afraid to ask questions.

[PRO250 1,506]

Im a big fan of the crow 214 214 cam. super maga drag cam we call it LOL, They work well in a stock engine. Ive made 170rwhp with one in my old black corty it was a beast for the junker it was. I got 14.5 out of it at the drags street tyres and 2.92 gears it would pull a tree out of the ground but would not rev very hard. My mate tryed to rev it and it droped a valve killing it, still hate him for it cause it was such a good thing for a $500 buck engine in cluding stock valve springs hence why it droped a valve

 

Heres little randys car same cam. it only makes 158hp but its been 14.6 on slicks like that, but likes to skid it more then race it. He is still learning but having a go as wes would put it

 

 



 

[gerg 10,871]

<br />Explain away Gerg!<br />

 

Ok some teminology:

 

• Advertised duration - the actual length of time (in crank degrees) the cam lobe raises the lifter off the base circle. It is for reference only, and is not the hard-and-fast rule for determining a cam's characteristics.

 

• Duration at 0.050" - the one you should really look at. It's measured when the valve is actually off its seat by 0.050", which is the industry-accepted standard at which air flow is enough to be measurable for this purpose. It also allows for all flex and clearance in the valve train to be taken up so you're actually measuring the end result.

 

• Lift - how far the valve is lifted off its seat. A general rule for crossies and Clevos, anything much over 0.500" lift needs roller rockers and good valvesprings/retainers. If you go heavier with valvesprings, then your flat tappet cam and lifters will wear out more quickly. This is why we say plan your engine well from the start so you don't build it twice.

 

• Overlap - on an engine with good breathing ability (ie bigger carb and extractors) there is more scope for the cylinder to be "scavenged" by using the inertia of the exhaust gas rushing out to create a vacuum in the cylinder to pull in more inlet air/fuel. This happens when both valves are slightly open at the same time, due to a longer duration of each cam lobe. This is called "valve overlap". It is most beneficial at higher rpm when there is less time for things to happen. A larger overlap at lower rpm gives over-scavenging, where under load, inlet charge can be pulled straight out the exhaust, unburnt. Also kills idle vacuum because exhaust gas is being sucked back in to the inlet manifold with both valves being open for so long. So less overlap = more tame street manners

 

• Lobe Separation Angle - drawing an imaginary line at the halfway point of each lobe, and measuring the included angle of these lines between inlet and exhaust gives you this number. It can alter the "personality" of your engine as much as any other aspect. For a given duration, a narrow angle gives a lopey idle and narrow rpm band, lots of overlap, is more "racey". Needs more compression as some cylinder pressure is bled off. A wider angle gives more sedate low-rpm behaviour and a wider torque curve, but needs less compression as cylinder pressure is higher (less bleed-off). A narrow LSA would be 106 deg, a wide one would be 112 deg. This is not necessarily a way of determining overlap but is an indication of where the "meat" of the valve openings occur.

 

• Advance/Retard - adjustable via multiple keyways on your cam sprocket, this aspect will raise or lower the rpm at which your cam will work in its optimum torque band. Advancing brings it on earlier, retarding brings it later. Sprockets are mostly made with +4, 0 and -4 deg keyways. Most cams should be installed "straight up" (0 deg) unless you're looking for a particular characteristic not available with any other choice in cam profile. They've done the homework for you so it's best go with their advice.

 

• Hydraulic/solid - cams are ground with different lobe shapes. Solids have a gentler ramp up than hydraulics to ease the shock on the other components. Hyd/solid cams are not interchangeable.

 

• Flat tappet - not quite flat but the lobes are actually ground with a slight (2.5 deg) taper to match the convex shape on the lifter face. The lobes also don't sit square to the lifter bores, but rather to one side. All this is to ensure that the lifter rotates, and so it and the lobe get even wear throughout their lives. Cams are made from heat-treated iron. Always use high-zinc engine oil with flat-tappet cams. They took a lot of zinc out of engine oils as it damages cats over time. You can get additives instead

 

• Roller cams - sit square in the lifter bore to line up with the roller on the lifter. Made from billet heat-treated steel. Lots of OEM manufacturers went with them since unleaded came about, not because of their "high performance" image, but because oils can no longer have the required additives that they used to have to prevent wear on high pressure areas like with flat-tappet cams/lifters.

[bigpaulo 239]

Gerg that was fantastic. That was by far the best explanation of cams ive ever read!

[gerg 10,871]

No probs, helps me understand it better when I explain it to someone else

[bigpaulo 239]

Now ive got my head around cams, I just need someone to explain to me how these aftermarket ignition systems work...

Im struggling to wrap my brain around the fact that you lock the dizzy when running a MSD. Having a locked dizzy that doesnt advance when the revs pick up or retard when starting and idling doesnt make any sense to me. Wouldnt it just make your car run like crap unless its screaming down the freeway??

Remember, explain this to me as if you were explaining it to your grandma...hahaha

[ando76 4,354]

If you use the programmable MSD (6al2 programmable) the ignition box takes care of the ignition curve.  you programme the amount of retard into the box. 

 

So you lock your dizzy out to say 32 degrees total and then the MSD box retards the signal from there at given rpm points - which you can alter to suit your application - cam and intended use. 

 

we use them in racing because of this feature but they are definitely at home on the street.  Think of it as an endlessly adjustable dizzy - no more sending your dizzy away to be re-graphed to suit cam etc. and they are far more accurate than any dizzy re-grapher can get and they don't wear like springs and weights in a Dizzy. 

 

Really they are just soooo good.  I love them as I have make awesome power gains with just this little box and the matching coil.  Best $500 odd dollars (US) you will ever spend.

[gerg 10,871]

Ok easy one that...

 

Your stock dizzy advances the spark timing in relation to both rpm and vacuum. As you modify your engine, the timing requirements change drastically. You could either "recurve" your dizzy to suit (trial and error) or use a programmable ignition unit like those you mentioned. It's still trial and error but the difference is instead of pulling your dizzy apart for every little change you want to make, you can tailor the curves exactly to what your engine wants at the click of a mouse.

 

The ignition unit cannot predict when the spark will happen, so in order to get the spark timed correctly, it retards it back from the maximum you set the timing at.

 

Say the absolute most timing your engine will need is 45 deg. You would set the locked dizzy at that and the computer will hold back the spark to the preset value you've put in. This is why the MSD program only ever mentions "retard" and not "advance" because that's all the computer is doing. The graphs on the MSD program show this too, with a maximum of 30 deg total able to be adjusted. The reason why only 30 is allowed is not because the computer has such a small range of adjustment, but because your distributor cap has only so much distance between terminals. Any more timing variation would cause problems like cross firing between cylinders and spark degradation from having to jump such a large gap between rotor and terminal.

 

So my example is 45 total, and you program your dizzy at a particular point to knock it back by 15 degrees. That makes it 30. Another point might need less again (say when cranking) so you take it back a full 30 deg, that would then be at 15. Are you catching my drift?

 

What I did was go to the MSD site and download the software for free. It's their way of marketing it in a way but it got me familiar with it before buying the product. See what you think.

[bigpaulo 239]

Yeah I understand that. Makes sense if you're running the programmable MSD. But about the other ignition modules like streetfire? They dont have any programing available, yet they appear to be marketed at your street level modifier...where I would have thought adjustable timing would be a hell of a lot more useful on a daily driver...