Author Topic: to skin a cat (m20 flywheel swap) (Read 17597 times)

rob_e30 · « **Reply #45 on:** March 16, 2007, 10:09:50 AM »

The M20 lightened flywheel with the M20 starter and no spacers, etc. seems to be fine. I've bolted it all up and cranked it a few times. Engine is not running yet as I need some software and fabrication work for the intake and exhaust but it's coming along!

romkasponka · « **Reply #46 on:** October 13, 2007, 12:03:02 PM »

My m20 flywheel (with 0.5mm preload) installed and runing with: m20 flywheel bolts, M42 starter motor, m20 325 free wheel pinion which was shortened to M42 free wheel pinion dimensions, 325 sachs clutch, 325 TOB. Everything works fine

5.4kg flywheel + 7kg clutch = 12.4kg

http://romkasponka.blogspot.com/2007/10/sankabele.html

p.s. It is with E36 gerabox.

Vladi · « **Reply #47 on:** October 13, 2007, 12:47:00 PM »

I didn't machine my flywheel before installing it...looks like i'll have to do it this monday...:mad:

ispierrot · « **Reply #48 on:** October 13, 2007, 03:34:11 PM »

Hello
I just changed the gear in the starter to make the conversion.

Shift_Now · « **Reply #49 on:** January 05, 2008, 05:17:07 PM »

So How has it been decided that the flywheel should be balanced after it is machined? Would your avarage machine shop be able to balance it, without needing to balance it on the crank?

romkasponka · « **Reply #50 on:** January 06, 2008, 02:36:39 PM »

Quote from: Shift_Now;40504

So How has it been decided that the flywheel should be balanced after it is machined?

Yes.

Shift_Now · « **Reply #51 on:** January 06, 2008, 05:03:09 PM »

But can a machine shop balance it? or does it have to be balanced with it attached to the crank? Sorry for all of the questions, I just want to cover all of my bases before I have the flywheel machined

romkasponka · « **Reply #52 on:** January 07, 2008, 02:36:03 PM »

It would be better to balance it with crankshaft if your engine is disassembled but you can balance only flywheel...

pbgd3skier · « **Reply #53 on:** January 12, 2008, 01:30:09 PM »

best to balance flywheel, then balance assembly.

If you balance the assembly with the crank out of balance and the fly wheel out of balance it will blow itself apart at high rpm.

Remember that some people balance their wheels w/ tires brakes and axle.

Appletree IS supercharged · « **Reply #54 on:** February 06, 2009, 11:36:27 AM »

Just to clarify, if you use an M20 flywheel lighten it to remove the step from the block side and then fit the M42 ring gear to it ( after the FW been moded to take it) you dont need the spacer and you can still use the stock m42 starter motor, and then just buy a 325 clutch assembly and a e21 323 T/O bearing.

another thing ive been thinking of is if you do the above and dont use the spacer then the flywheel is then going to be the thickness of the spacer further towards the block, will this cause a problem with the starter?

2002maniac did you use the m42 starter motor and was it with or without the spacer?

Cheers Matt

e30guydownunder · « **Reply #55 on:** February 08, 2009, 05:48:51 PM »

I have an early e30 323i flywheel (its 2 kilos lighter than the average m20 flywheel, so is 6kg from the factory, no need to lgihten

And will be bolting a 323i starter straight to the engine. Was intending to run the 3mm spacer to maintain factory spacing of the ring gear.

I'm also intending to run the m20 TOB as i got one with the clutch kit. I will be modifying the clutch fork if neccessary to get the extra travel as the e21 323i TOB was $190!!!!. But really i just think it will mean you have to push the clutch pedal further. Will have to find out with some testing yet.

When i am doing stage 2 or 3 of the build i will consider removing the flywheel and doing the modifications neccessary to fit the m42 ring gear...the m20 starter motor is 4kilos heavier!