Those dowel pins on the flywheel.

I was looking at this; and I wondered ; Why are those dowels so short. It would seem like they should be long enough to "fill" the flywheel and the crank . you know maybe another 3 mm in length. Does anyone make longer ones. and are there Oversize ones ? TIA

Reply to
Mr. K
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Well, you don't want them dowels to be so long that the bolt/washer starts riding on the pins instead of clamping down the flywheel.

I believe there are oversize pins and also smaller diameter pins.

A very common trick is to install an additional 4 pins, for a total of 8 pins. Called 8-pinning. I seem to remember the extra 4 pins are smaller diameter so the crank end would not look entirely like swiss cheese. They are drilled at a non-symmetrical pattern, so the flywheel, once drilled in the same pattern, would then only fit on the crank one way. Once balanced, it will stay balanced because it cannot be installed "off" position.

8-pinning is enough for most high performance engines.

One more trick beyond that is wedgemating. That means the mating surfaces are reworked to a wedge shape, and the tighter you run the bolt, the tighter the wedge shape grabs and holds the flywheel to the crank. It was popular on some high $$$$$ builds years ago, not sure if it was a fad or still around. 99% of builds will be just fine with

8-pinning and it's much cheaper.

Jan

Reply to
Jan Andersson

Every 8-pin flywheel and crank that I have, all the pins are the same

Jim

Reply to
Jim N

Wedgemating is still pretty commonplace on drag racing engines, in particular.

Reply to
bondo_sucks

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