1970-W30

Are the Buick and Olds 215 manual transmission flywheels interchangeable? In other words, are the outside diameters the same? And also are the outside diameters the same whether it's automatic flex plate or manual transmission flywheel? A flywheel is the last item I'm looking for to complete my 63 Buick 215 engine with Dual path auto to a T5 conversion.......Clutch and brake pedals, bell crank, clutch linkage, bell housing, throwout fork, flywheel bolts and a T5 trans. are all waiting for the elusive flywheel ......I know I can probably get one from D&D, but their prices are a bit scary, that will be my last resort....
Thanks in advance

joe_padavano

Yes, the OD and number of teeth on the flywheel ring gear are the same for both MT and AT, Buford and Olds versions. The Buick MT flywheels come in different varieties. There's one version that has a raised portion around the perimeter, creating a sort of recess that the clutch housing sits in. This was intended to increase inertia of the flywheel to make it easier to smoothly accelerate from a stop with a heavier vehicle and low HP motor. I've got one of these that I bought from Ken Dennison. I plan to have the inertia ring machined off to allow me to run a larger diameter clutch.

1970-W30

Thanks Joe, The reason I asked is because of an article I found from the British V8 forum which claimed the flywheels are 13.1" in diameter, not counting the ring gear, whereas the Roto 5 flywheel I have is closer 12.6" not counting the ring gear.
I'm taking a to a machine shop to see if the center section (where that funky flywheel damper resided) can be filled to be equal in height to the outer rim either by riveting or welding in a section. Current weight is 18 lbs, shooting for 20 to 25 after filling in the center section and drilling it for a GM 10.4 pressure plate. If that's a no go, then I'll have to go to plan B, keep on searching.......

joe_padavano

I can't see how the diameter "not counting the ring gear" is relevant. In any case, AT and MT cars use the same starter and the same starter drive pinion, so it isn't possible for the ring gear diameters to be different.