upgrade flywheel: 633 + shave + e28 clutch = light

[george graves]

What factory M30 flywheels are lightest? I've been told that a 633 flywheel and e28 clutch will work on a e34 m30..

1.) can anyone confirm this?
2.) how much can you shave from the flywheel?

Thanks....

ps - this isn't for a e34 - it's for a e30 I'm dropping a m30 into

[gale]

I can confirm that the e28 535i flywheel works just find on an e32 735i, which is identical in that respect to an e34 535i. E12 530i & 528i m30 flywheels will also work and are lighter than the e28 flywheels but I don't know by how much, nor do I know what a reasonable limit is for lightening. I'm not sure if you'd use an e28 or e12 pressure plate & disk for the e12 flywheel or perhaps they're one in the same?

I'm not a strong proponent for lightening flywheels on in-line 6's since the cranks are long & whippy at higher rpms & are dependent on the flywheel for damping, but as stout as m30 motors are, I'm sure I'm taking an overly conservative approach.

When you do settle on a flywheel, lightened or otherwise, take the new pressure plate to the machine shop & have them balance them both together as a unit, I guarantee it will rev smooth as silk all the way to redline & beyond. Mine was off 8 grams when I took it in & they commented 5 grams off is a significant amount. They resurface the clutch surface & drilled out the proper amount of metal to balance it to within less than 1/8 gram.

Good luck on the e30 swap, sounds like lots of fun!

[winfred]

we sold a e12 528i flywheel to a friend of the shop and ordered a e28 535 clutch kit for it, it all went onto his 92 535 just fine. i have another customer with a 85 535is that he installed a e28 m5 clutch on the stock 535 flywheel with no trouble


I'm not sure if you'd use an e28 or e12 pressure plate & disk for the e12 flywheel or perhaps they're one in the same?