Flywheel machining

[GunMetalGrey]

How much should be taken off the rear of an m20 single mass flywheel, for the swap? I believe that at one point I read that the back of the flywheel and the point where it mounts should be level, does the back just have to be further in than the mount point?
Getting my flywheel machined tonight and just want to make sure I don't mess it up lol.

[frankie591]

Get it machined to 1/16-1/8" from the ring gear

[e30rapidic]

depends....

I took mine down to flush with the ring gear, it's something like 11 pounds. But it will not idle with the factory 413 chip. I have the lightweight flywheel option on my TRM chip so its golden.

[ACHTUNG]

You can see more material could have been taken off closer to the ring gear. frankie591 is correct...take it to about 1/8" from the ring gear lip.

[TimKninja]

I only took 1/8th an inch off, then an angle grinder to the back of the oil pan.mint.

[328ijunkie]

i tell my machine shop 1mm off the ring gear.

[Lithium]

1/4 = 16 lbs

I took 1/4 inch off the back - Flywheel went from 19 to 16 lbs.
Fit perfectly. (Idle is kinda freaky with stock 413 though - Time for a chip)

[ScHpAnKy]

what do your idles sound like with your lightweight flywheels? Mine is down to about 11-13lbs and it's got a lopey idle like it's got a hot cam after it's been revving a bit.

[ACHTUNG]

I found another pic of a shaved M20 flywheel:

[GunMetalGrey]

Got mine back the other day, doesn't look quite as nice as the one above... was 110 for the back shave and the front re-surfacing.
Left a tad above the ring gear.

[drumad]

^mine was just like that

[Jand3rson]

I had them take mine down to about 1/16" above the lip around the ring gear.

[ACHTUNG]

Way more material could have been taken off both of your flywheels.

[Jand3rson]

Way more material could have been taken off both of your flywheels.

Certainly could have, and cost another $90 at the machine shop, for a negligible difference that I would probably not even notice. They took 4 lbs. off just doing what they did above. Anymore wouldn't really be necessary.

[e30rapidic]

Certainly could have, and cost another $90 at the machine shop, for a negligible difference that I would probably not even notice. They took 4 lbs. off just doing what they did above. Anymore wouldn't really be necessary.

not to mention going much lighter screws with your idle.