I'm not sure what's going on here but I thought he was talking about the longer shaft on the flywheel end of a weedie that was used to accomodate the clutch on some models? The point where you cut this long shaft off is close to 3 inches away from the seal.

The concern about heat getting into the seal concerns the double ended engines (mostly chain saw types and I think the Kioritz he was talking about) whereby there is a shaft sicking out the back end of the engine that must be sawn off.

There's another tidbit and that is on a Homelite 25 for example, there is a different flywheel on the long shaft engine compared with the short shaft. Being as one has a 3/8" shaft and the other a 5/16", The taper on the crank is a different size. The flywheels will interchange but it causes the flywheel to be too far forward or backward depending on which way you are swapping parts?

Enjoy,

Jim