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Years ago I changed out the clutch disc and pressure plate on my 83 L69 and didn't have a problem finding one at my local AutoZone. I am looking at replacing the same on an 84 L69 and it appears to be a little harder to find today. It's not your typical 10.4"/10.5" size. It measures 10", 26 spline input. The engine still has the factory lightweight flywheel. I can't remember if my 83 was a 10" or if it had the 10 or 26 spline.
AutoZone shows a 10" but it's not available; can't even order it. Rock Auto shows three 10" kits but in the actual details they all say they are 10.4".
Has anyone tried to run a larger clutch? Will it even bolt up to the factory flywheel?
Yes, a few options but even though the some of the titles say originally it was a 10" size the specs say the replacement is 10.4" or 10.5" and supposedly will fit.
I guess I need to do more searching to see if there is a 10" available.
It was originally 10.4", more or less. Replacements are also 10.4". People call that size all sorts of things. Don't put too much stock in somebody calling it 10" or 10½" and take that as some kind of absolute to-the-thousandth kind of accuracy.
10.375" is less than a business card thickness different from 10.4" around the edge.
But the disc and pressure plate on mine actually measures 10". The flywheel's friction does measure 10.5", however. I'm thinking the larger clutch is what I will be forced to buy. I just hope the bolt pattern matches.
Original '82-'85 V8 manual transmission cars did have a 10" clutch. GM started phasing in a 10.5" clutch during the later half of the 1985 model year.
The 10" clutch hasn't been available from GM or aftermarket for many years and the parts book even specifies replacing the clutch with a 10.5" unit
on earlier cars.
The bolt circle is the same between 10" and 10.5" pressure plates and the flywheel will accept either size clutch disc. You'll be fine installing a 10.5
clutch on your car. GM's original clutch supplier was Valeo.
FWIW, here is a picture of the correct 10" V8 clutch disc from my stash of new old stock 3rd-gen parts. GM part number 14079940. I believe it was
discontinued from service parts around 1989 or 1990.
Thanks Dens. Your info info correlates with what I have. The 84 I am working on now has the same 8-spring disc you show. Those years you mention pretty much matches what I experienced back when I changed the clutch in my 83. It may have been a few years later when I bought my 10" kit from AutoZone although I can't be sure what the actual size it wound up being.
The only thing I notice is when I change out the disc with the 10.5" it will match the flywheel surface but overhang the pressure plate although I don't see an issue with that. Just the wear pattern on the disc will be a little odd.
Maybe I should get the entire kit. That would make me feel better anyway!
I also noticed the Valeo kit is available AutoZone although it is a 5-spring.
A 10.5" clutch disc is not compatible with a 10" pressure plate. You must replace the entire clutch assembly when going to the larger size.
Valeo is a global company. Clutch design, tooling, and factory location has changed in the last 40 years. The clutch disc I have says Made In
France on the box(also has a big asbestos warning sticker!) I believe most Valeo clutches are made in South Korea now.
Good to know, thanks. I really couldn't see a problem in changing just the disc but also changing the pressure plate is obviously the correct way to do it. No sense in doing it half-assed.
Well, I should have just took your word for it, Dens, anything bigger than a 10" disc hits the pressure plate housing. I guess I was assuming the housing was a lot larger in diameter. Couldn't do it if I wanted to.
11-17-2022, 06:16 PM
