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Old 09-28-2019, 10:49 AM   #13
GOSFAST
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Join Date: May 2010
Location: Long Island, NY
Posts: 1,052
Default Re: Flywheel / Clutch Tips 8BA

I brought this back to add another very important "tip", we just realized it today on a customers flywheel/clutch ass'y. We actually had to rebalance it this morning!

We balanced it to "perfect" last night, took off the machine, inspected all the pieces closely and found this "bolt" issue.

Heads up here Joe, the "cover" we have here, a RAM piece/ 3/8-16 mtg bolts, measures about .150" thick, the lock washer (if you plan on using any) measures about .100" thick, and the "dedicated" pressure plate bolts we used for this setup have only a .190" long shoulder under the bolt heads. If you were to install this in your ride with these components I can all but guarantee you WILL have a vibration.

BEFORE any attempt to mount/balance the pressure plate (specifically) you MUST measure the actual shoulder lengths directly below the plate mounting bolt heads.

In this case here, the bolt "counterbores" average .190" deep (RAM alum wheel), with the cover at .150" thick, and the lock washer at .100" thick there is NO way the cover will be "centrally located" on the wheel where it's supposed to be.

There's a photo below (blown up some) to show the problem, the bolt on the left is an aftermarket piece, there's absolutely no room for the cover, the one on the right is a G.M. correct one, it has both enough room for the cover and to "center" it correctly! The one on the right has the "thin" washer already in place.

Thanks, Gary in N.Y.

P.S. Monday morning I'll be contacting ARP for some measurements on their bolts' shoulder lengths. If they meet our needs we will be putting some on the shelf. I also recommend NOT using any conventional lock washers, more as a precautionary measure, and going with some "thin" flat washer with "Loctite" on the bolts. I know ARP has these washer we need (I already have some here), but more will be ordered also if their bolt/washer combo is OK!
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File Type: jpg Pressure Plate Bolts-Washers.JPG (36.3 KB, 66 views)
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