Clutch shudder

Baker7888

G-Body Guru
Dec 3, 2021
665
115
43
Maine
Since no one has brought this up, is that '87 flywheel balanced to match the LT1? I know there are things that can interchange between the Gen 1 & LT1 but not sure if the external blance of the flywheel could be a cause if you do need a engine specific flywheel. Another thing is the fork pivot stud, is it also the right lenth for a A/G? This one may be far out there heading to left field but maybe it's just shorter than needed. Outside of the shudder might be a thing just because of your choice of clutch set but I'm leaning towards the flywheel as part of the issue due to not being a matched balance.
Those are possibilities. LT1 used a pull style clutch and the flywheel was different. My T10 required a push style clutch and g body required a 10.5” clutch to fit inside the g body bell so that is how i ended up with the 87 camaro flywheel. The fork pivot i used came with the manual kit (z bar, pedals etc) but matched the pivot that was still installed with the used bell i acquired (409 bell? Cant remember for sure) I know LT1 is externally balanced on the rear like a Gen 1. I bought the LT1 flywheel to compare and theb weights looked identical. FWIW. It seems many have geometry issues and what I found (mostly) worked for me was shortening the fork linkage rather than modifying the z bar. I do remember the fork that came with the kit did NOT match the fork I had that came with the used GM bellhousing. And comparing pics online I went with the used fork and ditched the kit fork. I should note the shudder is not extreme but it is still noticable and something i would like to get rid of. I can eliminate it by throttling the car up as i let out the clutch but i don’t like that. Part of the issue i think is my off idle bog which i hope larger squirters fixed. Other issue MAY be oil on the clutch.
 

pagrunt

Geezer
Sep 14, 2014
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Elderton, Pa
Those are possibilities. LT1 used a pull style clutch and the flywheel was different. My T10 required a push style clutch and g body required a 10.5” clutch to fit inside the g body bell so that is how i ended up with the 87 camaro flywheel. The fork pivot i used came with the manual kit (z bar, pedals etc) but matched the pivot that was still installed with the used bell i acquired (409 bell? Cant remember for sure) I know LT1 is externally balanced on the rear like a Gen 1. I bought the LT1 flywheel to compare and theb weights looked identical. FWIW. It seems many have geometry issues and what I found (mostly) worked for me was shortening the fork linkage rather than modifying the z bar. I do remember the fork that came with the kit did NOT match the fork I had that came with the used GM bellhousing. And comparing pics online I went with the used fork and ditched the kit fork. I should note the shudder is not extreme but it is still noticable and something i would like to get rid of. I can eliminate it by throttling the car up as i let out the clutch but i don’t like that. Part of the issue i think is my off idle bog which i hope larger squirters fixed. Other issue MAY be oil on the clutch.
Only the one piece rear main seal Gen 1's (about '86 & newer) will have an external balance fly or flex wheel due to the redesign of the rear of the crank. Now with those clutch linkage kits, there are more wrong parts than right parts it seems. Everyone (parts suppliers) seems to think the '64-'77 fork & bellhousings work which they don't. Even with the upper rod boot several places seems to believe either a 1st or 2nd gen F body boot is correct but far from it. Best is to source used original parts which will be correct dispite worn. I should dig into the parts bible to see what the p/n is for the fork ballstud for our cars just to post a reference. I really don't think the method on how the clutch disengages will make a difference either as it all works on a simular pivot point to compress the pressure plate to free the clutch disk. If you could get lucky to find the elusive '78 11" housing from a 350 Elky the stock LT1 flywheel could be put into the mix. This is just theories from me.
 
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Baker7888

G-Body Guru
Dec 3, 2021
665
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Maine
Well the noise is still present. Although I can live with it cause it only idles low when it’s cold. My clutch felt like crap, engages right off the floor and doesnt want to shift as easily. So i kept the spring but adjusted back to where it was. Right now I am almost convinced the shudder is due to an off idle lean condition which i have created a seperate post about over in the fuel section.
 

Bonnewagon

Lost in the Labyrinth
Supporting Member
Sep 18, 2009
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engages right off the floor and doesnt want to shift as easily
Yeah, it was adjusted too far down. Not releasing enough. As for the shudder, does it go away when you raise the rpm's to say, 1500 or so?
 

Baker7888

G-Body Guru
Dec 3, 2021
665
115
43
Maine
Yeah, it was adjusted too far down. Not releasing enough. As for the shudder, does it go away when you raise the rpm's to say, 1500 or so?
I think so. I’ll have to try to be sure.
 

ELCAM

Royal Smart Person
Jun 19, 2021
1,127
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You really need to determine if there is oil getting on the clutch, nothing will work right if the clutch is getting contaminated.
 
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Baker7888

G-Body Guru
Dec 3, 2021
665
115
43
Maine
You really need to determine if there is oil getting on the clutch, nothing will work right if the clutch is getting contaminated.
Agreed. Just trying to cross all other “simple” options in hopes of getting lucky. I do have a few questionable things going on. Weather is still good and I dont want to do anything major until the season is over. I can still tweak and tune and road test with the transmission in the car. I think this winter i will pull it and address the leaks. Noise may be coming from transmission
 

Bonnewagon

Lost in the Labyrinth
Supporting Member
Sep 18, 2009
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A T-10 is a pretty old model. It is basically a Borg Warner three speed, modified to be a four speed. When horsepower rose, it did not keep up, so GM changed to the Muncie. Then that was even superseded by the Super T-10. The ST-10 had a much wider selection of gears, and is much more available than a Muncie, or T-10. I had a friend with a 1968 Firebird 400, who's hobby was getting the cops to chase him. He always got away, but he could twist Muncie main shafts like spaghetti.
 
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Baker7888

G-Body Guru
Dec 3, 2021
665
115
43
Maine
A T-10 is a pretty old model.
You really need to determine if there is oil getting on the clutch
Only the one piece rear main seal Gen 1's (about '86 & newer) will have an external balance flywheel
Ok Im back. The shudder is basically gone, mostly from downsizing to a 600cfm carb (thanks to 78Delta88 for all the technical data) and adjusting the clutch for more of a mid-travel engagement.

However. This knocking is driving me nuts. Please see my first post, third paragraph.
I have the noise traced to inside the bell housing. Definitely thinking it shouldnt sound like this. I have a couple ideas and things to look for. Hoping it’s not going to be an elusive issue. Any thoughts in the meantime?

I am hoping to find loose bolts maybe. If not, maybe worn transmission input shaft, or maybe some visual damage. Lastly i can try running the motor with flywheel only and see if the noise is still present.

Wondering if it is infact thrust bearings. Would i be able to measure endplay with motor in vehicle?
 
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Bonnewagon

Lost in the Labyrinth
Supporting Member
Sep 18, 2009
10,596
14,361
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Queens, NY
Wondering if it is infact thrust bearings. Would i be able to measure endplay with motor in vehicle?
Probably. Use a magnet based dial indicator, mount it to the block, with the tip on the flywheel. Pry the flywheel back and forth. Any movement is your end play. Compare to stock specs. Was the engine originally an automatic, or manual? An auto would have virtually no thrust wear, while a manual is indeed suspect.
 
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