02 September 2019

Then Why

"The flywheel does not use an alignment pin..."

Two things, GM.

First: If you don't use that pin, why are both the crank and the flywheel drilled for it?

Second: I noticed that those holes were lined up when I took the old one off.  Might as well of had a pin, huh?


  1. Angus, I take it the pin is removable after you line up and install the parts?

    If the pin was missing but the holes line up on the old parts you took out, it tells me that GM has the bloody flywheel, pressure plate and whatever else balanced without the pin.

    If the pin is left in when you assemble it, you may be introducing an off balance object.

    Just check a bit more on this before you leave anything "in" that was not there when you removed the old parts.

    As to the pressure plate, same applies as above, but if the thing looks 100% symmetrical from every angle, it may not matter how it is oriented. Been 45 years since I did a complete rebuild and I don't recall things being this complicated, but then mine was a bog standard 327 from 1965 and not a high performance CVette.

    1. No pin is present and the manual says it's not used.

      I just think it's interesting that the holes are still there, aligned with each other, and unused.

      Near as I can tell, this matters a bit but since it's internally balanced not as much as it could.

      I've not found anything indicating that the pressure plate needs a particular orientation when a new one is installed.


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