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Discussion Starter #1 (Edited)
Hello everyone, I recently put a new pressure plate and disk in my 70 w/out surfacing the flywheel. Once completed, whenever I would reach the release point it would not only chatter but make a terrible raspy sound. I know you're all thinking the disk must've been installed backwards; however, I just pulled it all back apart and it wasn't. The springs on the disk were riding on the bolt heads of the flywheel even though it was installed correctly. I took the entire kit + flywheel back to Napa for examination, and the recommendation was to order a new flywheel and re-check the tolerances. I guess my real question is if the flywheel is this far out of spec, why didn't it make noise with my old worn out disk? FYI engine is a 455, M21, w/ Hays flywheel resurfaced once 10 years ago. The Napa rep believed the flywheel bolts to be correct, very shallow, they look almost like studs w/ a nut screwed half way on

Just realized I probably should have posted this in the tech section, can a moderator please move if necessary.

Thanks in advance
 

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Discussion Starter #3
It's very possible the flywheel could be wrong. I just ordered one from year one, it appears the same as my old one, but it's tough to tell from the thumbnails. It measures 2-3/4's for the crank just like the ones advertised. I guess we'll see.
 

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I would say...A parts match issue. Possibly the wrong diamater new clutch. It is pretty difficult to cut a flywheel that much...especiually since you didn't cut it at all.......Eric
 

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It's simple: the flywheel is too shallow at the flange area for the new disc. IF the springs are hitting the bolt heads, and the springs on the old disc did not, I would blame the new disc. If, as you say, you are unsure of the flywheel's origin, then the flywheel AND old disc might be some other application. So, a new GTO-spec clutch may not work. The new flywheel should fix your problem. You could measure the clutch disc heights to check. I would also check the depth of the new Pontiac flywheel and compare it with the old one. You'll get it fixed. BTW: I've had good luck with old flywheels that I didn't want to remove to machine by doing the following: Check runout with a dial indicator, if not warped, deglaze flywheel with one of those air powered brillo discs. Clean with brake-clean. Works well, and won't thin out a flywheel. Won't work on a cracked or warped flywheel, though. Good Luck.
Jeff
 
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