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Need advice on msd on worked 250 + carb sizing

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Hi guys, I'm fairly new to this and this has probably been discussed several times..aha

Looking at getting an msd 6al2 for my Crossy. What do u guys think, good choice? Also what dizzy will go with that? Probably need a new coil as well yea?

Any other things I should be aware of..

Engine mods:

Is has a 250 crank that was balanced and polished and knife edged counterweights. A lot of time went into the bottom end. 200 rods were shot peeved and polished with bigger rod bolts. The rotating assembly was blueprinted and Balanced. The block was line bore honed, machined, crack tested, pressure tested, it has oversized pistons (I think 30 thou). Flat top custom pistons (11:1 comp) The block is also machined to zero deck. The head is ported and polished, has oversize valves, has double valve springs and Teflon stem seals. Also has hardened inserts and bronze valve guides

Double row timing chain. All new gaskets and a copper head gasket. TE distributor has been graphed to suit the cam and has a bronze dizzy gear to suit the camshaft also. The fuel pump on the car is also modified and has a stronger spring and diaphragm to maintain enough fuel pressure.

It's running a mustang 5 speed manual..

My plans for the next mods are msd ignition, TFI dizzy, 4brl manifold with 650dp, roller rockers, but before all that I need to swap my 2.77 diff for a 3:45 as it need it..aha

The motor revs to 6500 pretty easy..

Also what size carb would u guys recommend? 465, 600, 650.. Sort of want to go double pumper..

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Nice engine by the sounds mate. The 6al2 will work great for you, and you could look at a blaster HVC2 coil part# 8253. That's the setup I will be using on my solid roller cam crossflow. Speaking of cam you didn't mention anything about the cam in your post but guessing it is a hydraulic as you havent changed to rollers yet. Will need some cam specs and intended use for the car to help with carb selection.

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crank trigger is the go if you want to rev it like that - it is a reasonably cheap conversion and makes a massive difference. 

 

The MSD universal crank trigger unit is the go.  just gets rid of all the problems associated with either dizzy (TFI or EST). 

 

Sounds like a solid combo.  I'll bet my left nut the copper head gasket leaks.  never seen one seal properly yet and really they are overkill with that compression ratio.  I have used standard style gaskets to 14:1 comp without an issue.

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Nice engine by the sounds mate. The 6al2 will work great for you, and you could look at a blaster HVC2 coil part# 8253. That's the setup I will be using on my solid roller cam crossflow. Speaking of cam you didn't mention anything about the cam in your post but guessing it is a hydraulic as you havent changed to rollers yet. Will need some cam specs and intended use for the car to help with carb selection.

Cheers mate.. I don't know the specs of the cam sorry, all I know is it makes power from 2500 - 6500.. Yea it's a hydraulic cam..

Probably just a tough weekender street car.. Want to see how much I can get out of it..

 

 

crank trigger is the go if you want to rev it like that - it is a reasonably cheap conversion and makes a massive difference. 

 

The MSD universal crank trigger unit is the go.  just gets rid of all the problems associated with either dizzy (TFI or EST). 

 

Sounds like a solid combo.  I'll bet my left nut the copper head gasket leaks.  never seen one seal properly yet and really they are overkill with that compression ratio.  I have used standard style gaskets to 14:1 comp without an issue.

Can you explain what a crank trigger is? Never heard of one before.. I rarely rev it to 6500 maybe once a month, most I do when I drive it is around 5000...

Don't think it leaks, never had an issue with it leaking before...

Cheers guys..

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It will leak - they all do.  look for excess breather can deposits or oil in the water.

 

ok well if you are only going to stay around 5000 - leave the dizzy in.  If you want to see what crank trigger is - have a look in the for sale section - glen's engine has it - think Slydog started the post. 

 

basically a crank trigger is a set of 3 magnets that pass by a trigger to give a better signal to the MSD as to the engine's position.  '

 

The problem with either dizzy (TFI or EST) at consistent high rpm is that spark scatter occurs due to the dizzy being driven off the cam shaft via the dizzy gear.  this creates issues at high rpm which leads to inaccurate timing.  With a crank trigger system the MSD gets its signal from the crank and therefore it is much more accurate at rpm because it is not influenced by the harmonics. 

 

It makes HP in those applications because of the more consistent timing.  Been proven more than once now.  For your application - probably overkill.

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I know all the folks in the know swear by carbies around the 600 mark, but here's an article where they test a whole bunch of Holleys on a stout 383 SB Chev, and the results are very interesting.

 

http://www.superchevy.com/how-to/148-0403-seven-holley-carbs-test/390-cfm.html

 

The smallest one they chucked on, (the 390) despite obviously choking an engine that size, still made 409 hp and got good torque all the way up to it.

 

So if you plan on making anywhere near that power (and i doubt you will) maybe a smaller carby like a 390 or 465 is a smarter choice.

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It will leak - they all do.  look for excess breather can deposits or oil in the water.

 

ok well if you are only going to stay around 5000 - leave the dizzy in.  If you want to see what crank trigger is - have a look in the for sale section - glen's engine has it - think Slydog started the post. 

 

basically a crank trigger is a set of 3 magnets that pass by a trigger to give a better signal to the MSD as to the engine's position.  '

 

The problem with either dizzy (TFI or EST) at consistent high rpm is that spark scatter occurs due to the dizzy being driven off the cam shaft via the dizzy gear.  this creates issues at high rpm which leads to inaccurate timing.  With a crank trigger system the MSD gets its signal from the crank and therefore it is much more accurate at rpm because it is not influenced by the harmonics. 

 

It makes HP in those applications because of the more consistent timing.  Been proven more than once now.  For your application - probably overkill.

I had a look and couldn't find oil anywhere.. Must just be lucky..ahaha

Thanks for the info dude, yea sounds a bit overkill for what I'll use it for..

 

Would I notice any difference if I used different coils? Like the blaster 2 or the hvc2 coils?

 

If using a dizzy, use a TFI. Easiest way to run it is to remove the module on the side and replace it with an EST plug or connect directly to the prongs. Very easy. A new Bosch coil is fine or get one from MSD.

Any good carb over 570cfm. I would use a nice choke-less 600 DP.

Thanks for the suggestions so far I think I will go 600..

I'll get a TFI dizzy too.. Would swapping the plugs just make it easier to install?

Thanks

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I know what your saying gerg, but these engines love big carbies - it goes against all the theories and I think it is because of the oversquare design that makes them throw all those carby calculators out the window. 

 

On a tough crossy used in anger I agree with Matt's recommendations.  On the same engine used as a commuter with the occasional stab I would go with the 465. 

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Apologies for the Hijack, so it's best to run a TFI dizzy without the module when running it with a MSD 6aL? I have heard of people running it with the module just fine.

 

And how do you get the EST plug to work with it? Unscrew the plug adaptor off EST dizzy and bolt to the TFI dizzy?

 

Back to OP's question. I have just run a Bosch HEC716 Coil (OEM spec) with a EST dizzy, this is on a worn out stock 250 though.

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Apologies for the Hijack, so it's best to run a TFI dizzy without the module when running it with a MSD 6aL? I have heard of people running it with the module just fine.

 

And how do you get the EST plug to work with it? Unscrew the plug adaptor off EST dizzy and bolt to the TFI dizzy?

 

Back to OP's question. I have just run a Bosch HEC716 Coil (OEM spec) with a EST dizzy, this is on a worn out stock 250 though.

 

The module is just another thing that burns out on a 30 year old part that is not needed when used with a MSD that accepts Hall effects input. The module is just a sink to trim the volts back to 5volts logic and WILL fail eventually.

 

Undo the 2 screws holding the Grey motorcraft plug on and fit the EST uni in it's place to go from 6 wire out to 3 and no module. Now the only thing that can fail is the pickup but there few and far between.

 

HVC coil doe's make a difference on an banger engine for sure.   

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Good work Sly. Couldn't have written it better.

 

Agree that a smaller carb could be used for a more commuter friendly engine. Will loose out above 5-5,200rpm, but how often do you use revs above that? But then again a smaller cam will make it more friendly as well.

 

If you have a big cam the carb might as well match in my opinion.

 

Good thread!

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I've been looking at the msd 6al-2 and there are two designs.. 1 of them is u can plug it into the computer and make your own curve and the other just has like 4 dial u turn..

Which one did u guys put in? And why? Cheers

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6AL-programmable, never looked back. While not quite up there with the tuneability of an aftermarket ecu, they do what they're designed to do, and well. Instead of a 3D map like on an ecu, they have 2 separate curves (rpm and load) that subtract timing from your preset max advance on 2d graphs, to an absolute total of 30 degrees, 25 on the graphs and the other 5 through rpm or switched retard. They have launch retard and step retard functions too, as well as rpm limit. Quite impressive for the money. Need a GM map sensor with it too

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I've been looking around at different ignition boxes and this is my questions..

im tossing up whether to get the 6al-2 or the street fire..

I know the 6al-2 has a lot more functions but I don't think I will use any of them..

What I'm going to do is fit it and get is professionally tuned and I assume they would set the ignition to where they reckon, and limiter and stuff like that..

So for my use would I gain any more power with the 6al2 box?

Is it worth that much more than the street fire for me?

Cheers, any help or opinions would be great..

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The 6al2 PROGRAMMABLE is unbeatable - FULL STOP.  The street fire is strictly a locked timing unit which is far from ideal - especially on a street car.

 

If you are going to spend the coin - spend it once - buy a 6al-2 programmable.

Sorry, what do you mean when u say locked timing only?

Is the 6al2 fully adjustable?

Just want to make the right decisions before I go ahead.. Thanks

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Firstly there are 2 different 6al2's. One clearly states it is programmable the other will not mention it at all. You want to buy the Programmable one. The reason being is you can hook up a laptop to the programmable and set all your own maps for timing or the dyno operator can set it all up. Think it of this way, the programmable one is just like getting a full custom tune on any fuel injected motor with mapping to suit your engine. A locked timing is just like getting a tune for a fuel injected motor where you can't change a thing and what you get is what you get.

This is a very simplistic view point of the topic but is the easiest way I understand it. The locked timing has it's place in race cars but on the street where driving changes from wide open throttle to start stop traffic and anywhere in between it can be difficult to get the tune right. Yes you can use locked on the street but as always there is a compromise, where as the 6al2 programmable can be programmed at 100rpm increments with a laptop and the entire tune can be changed with a click of a mouse button.

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The Streetfire does not have the ability to alter the signal received from the distributor. So whatever you set at the crank is what you have - from idle to whatever your rev limit is.  Very popular in 80's drag racing scene because the engine is tuned to perform over a very narrow (2000 rpm) band.

 

The 6AL2 PROGRAMMABLE has the ability to take the signal from the distributor and give you an advance curve, just like your engine had when it left the factory.  In reality the 6AL2 takes the signal from the distributor and retards it (via the run retard Graph - advance curve, backward if you like) to give the engine what timing it needs throughout the rev range is 100 rpm increments.

 

TO make it SUPER SIMPLE - THE WORST IMPROVEMENT I HAVE SEEN ONE OF THESE 6AL2 PROGRAMMABLE IGNITIONS MAKE IS 15RWHP.  With a moderate curve I improved this another 15 RWHP.  That is 30 RWHP gain when compared to LOCKED TIMING.

 

I can not EMPHASISE how good these things are - BUT at the end of the day - DO what YOU want.  I can only advise on what I and MANY others have found with using the 6AL2 on a crossflow. 

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Once again

wagoon= simplistic dribble that compares apples to oranges using bananas as an example

 

then

 

Someone who knows what they are talking about= someone who knows what they are talking about and makes sense with a technical bases to the argument

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I'm looking at roller rockers for my Crossy and I found a set of crane ones, but the ratio is 1.7:1..

I know most people run 1.7:3 ratio rollers...

Might be a dumb question but want to know what's the difference and will they work the same.. Cheers

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