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aluminum flywheel mounting
Posted by: DOUG WARD ()
Date: June 19, 2022 12:27PM

Hi guys, this is probably going to be a question for those of you that are in to racing, but here goes.
I am installing a Harvey / aluminum flywheel on my LM engine. The flywheel is for an early engine so I will use an early clutch too. Any disc should work. My question is; do I need to use the large ( 3" )washer that is used when bolting in a stock flywheel? The aluminum one is about 3/8 inch thick at the mounting/ bolt area & the stock one is about 1/8 inch thick.

Doug Ward
Orange, Calif.
65 Corsa 180, 64 Monza convertible, 61 Lakewood, 61 Monza


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Re: aluminum flywheel mounting
Posted by: dryenko ()
Date: June 19, 2022 02:10PM

Using the 6 hole plate will make the standard GM clutch disc rub the heads of the bolts , so no.
I recommend a AN series close fit washer, instead, in the thicker of the two thicknesses available.
The holes in the washers may need to be enlarged slightly to fit the bolts.
Chamfer the washer hole slightly on the side that fits against the radius under the head of the flywheel bolts.
To provide clearance for that radius.

Bob C aka Dryenko
Dobson, NC 27017

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Re: aluminum flywheel mounting
Posted by: DOUG WARD ()
Date: June 19, 2022 08:57PM

Hi Bob, If I understand you correctly, you are saying to NOT use the 3" disc & instead use just washers under the bolt heads.I had mounted the flywheel earlier today & when I removed the bolts, I saw that the bare bolt head had scored the aluminum flywheel pretty badly. My main concern was that the aluminum flywheel might need the additional stiffness that the large washer would give it. It's center section IS pretty thick so it will probably be OK.I re mounted the flywheel using just the small washers. Torgued them to 50 ft lbs.
I appreciate your feed back. Thanks.

Doug Ward
Orange, Calif.
65 Corsa 180, 64 Monza convertible, 61 Lakewood, 61 Monza


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Re: aluminum flywheel mounting
Posted by: vairmech ()
Date: June 20, 2022 04:46AM

I have a thin spacer disc that I use for my dual disc clutch. I do grind the stock bolt heads a little but just the stamped in castle top.

You can also use the late bent finger PP. All you need to do is add enough washers to each bolt to equal the step in a late flywheel.

Also if you are doing anything other than street driving a stock clutch disc has a very good chance of spitting the disc out. I have a carbon/kevlar disc that has a thin metal backer that keeps the disc from breaking and I also have my fiber tough disc back in stock. That is the one I used with my aluminum flywheel for several years with no wear to the flywheel.

One other thing do NOT use an aggressive disc on the Schaefer flywheel!

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: aluminum flywheel mounting
Posted by: DOUG WARD ()
Date: June 20, 2022 09:31PM

Ken, thats good info. I went ahead & used an early pressure plate since I had a fresh rebuilt one with a new finger center section in it. I only do street driving any more & like the fast revving feature a light flywheel gives to the engine. I know that there will be less torque available but I can live with that.
I'll revisit your suggestions if I ever need to pull the power train again.Thanks.

Doug Ward
Orange, Calif.
65 Corsa 180, 64 Monza convertible, 61 Lakewood, 61 Monza


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Re: aluminum flywheel mounting
Posted by: Mike Stillwell ()
Date: June 21, 2022 03:13AM

Doug - You will need to shim the clutch fork stud on the diff as well. Approximately 3/8”, IIRC.

Mike
YS-117

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Re: aluminum flywheel mounting
Posted by: texas yenko dude ()
Date: June 27, 2022 07:26AM

You could use the late pressure plate with the early alumn flywheel. That is what we use in the race cars. You need to glue shims to the pressure plate to space it correctly. It works like a champ.

Texas YENKO Dude
YS-070
YS-199
YS-320
Southeast of Disorder


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