third gen t56 swap, pressure plate issue

[redsoxsstink]

ok so... T56 swap is done in the car when i press the clutch the clutch fork hits the front of the pressure plate. how i know? grinding noise, and the pressure plate was painted now its not.

things to note:
factory 5 speed car (1986) so using stock pedals
new AC-delco master/slave set up
LT1 t56 (shifts gears fine)
GM lt1 flywheel, this is a 1pc rear seal SBC so this should be ok
ebay clutch
http://www.ebay.com/itm/150879006557...%3AMEBIDX%3AIT

any ideas?

[V]

fork bent? or not properly inserted into TO bearing? disc not in backwards?

[FlyingDutchman]

What bellhousing are you using? Maybe it doesn't matter but if the flywheel/PP assembly is fixed to the motor and the clutch fork is fixed to the trans, maybe clearance issue? Can you see what part of the fork is touching the PP?

[redsoxsstink]

yes i can see where the fork is touching the pressure plate, should have gotten a pic, i can do that later.
the bellhousing is the stock LT1 bellhousing.
as far as i know the fork is not bent and is properly inserted on the throw out bearing, and clutch disc is properly installed (my father helped with the fork bc i couldnt figure it out, ASE master tech at chevy)

from my research it seems like this issue is fairly common and there is no rhyme or reason and multiple ways to fix it. grind the clutch fork, let it clearance itself, use 4th gen pedals, shorten the master cylinder push rod, build a stop into the third gen pedals.

[WildBillyT]

I wonder if it's a stock pedal issue. Sounds like it may be fork geometry.

I would not let this clearance itself.

[FlyingDutchman]

I was going to say maybe the 3rd gen pedals with LT1 master/slave is causing the fork to over extend and rub. I would certainly fix it right by either swapping pedals or making a stop for your 3rd gen pedals as opposed to letting it grind away your fork!

[redsoxsstink]

i probably agree it is a geometry issue, like i said it seems to be a hit or miss issue that not everyone has. i think im gonna make a stop.

some people cut and thread that master, but i think this is sketchy. what if it breaks? now im stranded, atleast if the stop breaks i can baby it home

[WildBillyT]

Originally Posted by redsoxsstink

i probably agree it is a geometry issue, like i said it seems to be a hit or miss issue that not everyone has. i think im gonna make a stop.

some people cut and thread that master, but i think this is sketchy. what if it breaks? now im stranded, atleast if the stop breaks i can baby it home

Huh. To me that's not a bad solution as long as you get proper jam nuts and such.

My mechanical linkage is all threaded rod and rod ends and it's been perfect.

[redsoxsstink]

i suppose it wouldnt be bad with the proper hardware like you said, idk in my head it just doesnt look right. i also really dont want to have to yank the master/slave back out since that requires removing the brake booster which was a major PITA for me. id love not to ever have to crawl under my dash again.

[ar0ck]

I do have a set of 4th gens Manual pedals if you decide to change your mind, I believe they need to be modified though to fit in a 3rd Gen.

[WildBillyT]

Originally Posted by redsoxsstink

i suppose it wouldnt be bad with the proper hardware like you said, idk in my head it just doesnt look right. i also really dont want to have to yank the master/slave back out since that requires removing the brake booster which was a major PITA for me. id love not to ever have to crawl under my dash again.

Then go for the stop, just make it something really positive that won't give or break. If you have to pull the trans out later maybe look into the master mod.

[redsoxsstink]

decided im just gonna cut and thread the rod

correct me if im wrong, maybe im overthinking this. by shortening the rod this will reduce the amount of fluid traveling to the slave but also changing the overall position of the clutch pedal when my foot is not pressing it, this is what i want.

for some reason in my head im thinking this will just change where the clutch grabs and not change how much fluid is displaced.

[sweetbmxrider]

Aren't you shortening the throw? Same fluid pushing, different length rod, less disengagement, no fork to pressure plate.

[redsoxsstink]

yes shortening the rod, so it shouldn't displace as much fluid as the longer one, fixing my issue

[sweetbmxrider]

You are shortening the reach of the rod. I don't see how this would effect the fluid? I must be misunderstanding.

[NJSPEEDER]

Shorter rod would mean lower resting height for pedal, so less throw from resting height to pedal stop.

[redsoxsstink]

i want to shorten the rod so when i push the pedal down it displaces less fluid compaired to the long rod thus fixing my issue of the slave over-extending causing the fork to contact the pressure plate.

is this wrong and all im actually doing is adjusting the height of the pedal?

[redsoxsstink]

so i threaded and shortened the rod for the master. it works flawlessly now. trans shifts great and clutch grabs good.

heres some pics of the contact the fork was making with the pressure plate and another of the master mod

[sweetbmxrider]

Glad it works, however it works

[L695speed]

I was gonna chime in, but got real busy before I saw this thread. With the third gen pedals it is a hydraulics issue. Too much fluid moving, too much fork movement. Most people do what is done here, thread and make the rod adjustable. I went a different route, and used a Cavalier Z24 slave cylinder, with a LT1 T56 master. Third gen pedals. I have progressive engagement, with full engagement at maybe a couple inches from the floor.

On another note, the fourth gen pedals will work, but, and be warned, people have reported cracking firewalls because they don't bolt in like the stock third gen ones do. Some of the holes do NOT line up, particularly the one going into the upper cowl. Use the third gen pedals, they're not exactly rare, and they bolt into the car properly.