84TA327

I have an LT1 T56 that I'm swapping into an 84 Trans Am that was already a 5 speed car, so I have 3rd gen pedals in the car. I have a 2pc main sbc, so I am using the swap flywheel with a competition clutch. I bought the 4th gen master/slave set.

My question is, I've heard that the factory 4th gen hydraulic setup on third gen pedals creates issues with the clutch fork hitting the pressure plate. What are my best options using what I have, and what else do I need to do hydraulic wise to get this all to work properly using the 3rd gen pedals and 4th gen hydraulics? The flywheel and clutch are both ordered and on their way, so I have a few days before I can really get working on the car. Thanks in advance for any info.

sofakingdom

iTrader: (1)

The 3rd gen pedal has the stud farther down on the pedal (farther away from the pivot), thus strokes the master cyl MUCH farther than the 4th gen does. With the setup you (and I) have, people have been known to bottom the diaphragm against the flywheel bolts.

The 4th gen pedals fix this. 4th gen pedals + 4th gen hydraulics + 4th gen clutch = everything fits right.

But with the 3rd gen pedals, all you have to do is, not push the clutch all the way. Doesn't take long to figure out how far it has to go.

Speaking strictly as someone with several years of driving around EXACTLY the same setup as you are proposing.

84TA327

Would there be any way to shorten the master cylinder arm? I want to eliminate any possibility of anything being wrong.

sofakingdom

iTrader: (1)

Problem isn't the MC. It's the pedal.

The stud is farther from the pivot than it needs to be. It strokes the rod too far.

Doesn't matter if the MC rod is one inch, or one foot, or one mile long; if it's supposed to move 2" and instead it moves 4", or whatever, the problem remains. You can cut or extend the MC rod all you want and not really have any effect on the problem, except if you shorten it SO far that it disengages from the MC piston at the top. But then, instead of the clutch action being at the top where it's supposed to be, it'll be halfway down or wherever the slack finally gets taken up. It'll merely SUCK.

Either use the 3rd gen pedals and learn to live with it, or get 4th gen pedals.

jmd

iTrader: (4)

I've driven both with an LT1 T56
Would I rather:
- swap pedals
- have an adjustable master
- run a larger bore slave cylinder
- shim something somewhere
. . .
I'd rather swap pedals.

Not because I can't drive a slightly stiffer pedal or fix any issues related to the mismatch. But because I like to make things drive nicely so "anyone" could drive it without issue (read: wife or me in my long commute.)

And, I like simplicity when buying replacement parts. Instead of "yeah, 89 Camaro master, 89 Cavalier slave, 95 Camaro hydr. line . . . " you can just walk in any parts store anywhere and buy all 3 for the same car. Sometimes as a complete set so you save time installing & not having to bleed it much.

In other words, if there's no functional benefit to the mix-n-match game, why not simplify?

Boyd Coddington, when interviewed about Chezoom back in the 90s, said the vehicle could be serviced at any Chevy dealer anywhere as a Vette. And that's not a bad mindset when building a car. Your only custom piece needs to be the flywheel.

vbMike

iTrader: (2)

You could add a stop to the back of the pedal or somewhere on the firewall to prevent the pedal from being pushed too far. That's what I did and worked fine. No problems.

86iroct5

i had the issue of the fork hitting the preasure plate with the third gen pedals and 4th gen hydraulics. i shortened the master cylinder rod and it works perfectly.

this is a pic that was hijacked from another thread on here i think.


sofa.. i am going to disagree with your statement about the length does not matter. i didnt think shortening the rod will do anything but it does.

racerkilla

I run my t56 with the stock 3rd gen pedals and master. I used a 1988 cavalier slave cylinder on the trans(direct bolt on) and its larger in diameter at 1.25 then the stock t5 one. My clutch pedal is super easy to push and doesn't bottom out fork.

formula00ra

iTrader: (1)

can I use the 4 gen pedals, hydraulics, clutch on a t5? ( I have a 90 formula)