M20 flywheel swap/ lightening

Post Sun Mar 17, 2013 5:26 pm

Right i have m20 flywheel with spacer and sachs clutch kit but misplaced release bearing so just wondering what is best release bearing to use m20? And how light do i need flywheel to be? Also how much should it cost to be done roughly?[/u]

Post Mon Mar 18, 2013 12:47 am

What gearbox are you using?

Post Mon Mar 18, 2013 9:01 am

Gearbox doesnt make any difference, if your bolting the M20 flywheel to an M50/M52 it will need to be machined on the back to clear the sump. The weight isnt the issue, its clearance, but while its on the lathe its a bonus to take a load more weight out

I get them down to 5.5kg odd from 8.3 standard

Pm me if you want one doing

Post Mon Mar 18, 2013 9:06 pm

It doesn't make a difference to the flywheel but it does for the release bearing.

Post Mon Mar 18, 2013 9:39 pm

Im using a getrag 250 box mate, supposedly I need E30 325i linkage? and a 325i prop?
Still not sure what prop I need yet

Post Mon Mar 18, 2013 11:17 pm

Not 100% on this information as I never really considered using the Getrag 250.

The prop should be out of an e36 325i. That will be the correct length and bolt up to the e30 diff. Use the e30 centre bearing.

The release bearing should be the euro e21/e30 323i version (21-51-1-204-525). It's longer to make up for the thinner single mass flywheel that you're swapping to. That said the original e36 325i bearing will probably work just fine too.

Can't really help with the linkages.

Hopefully someone else will confirm/correct/complete my information.

Post Mon Mar 18, 2013 11:36 pm

TimJ wrote:It doesn't make a difference to the flywheel but it does for the release bearing.

It doesnt make a difference to the bearing either, here is a list of all the cars/engines the standard bearing is fitted to -

http://www.realoem.com/bmw/partxref.do? ... showeur=on

Post Tue Mar 19, 2013 2:28 am

DanThe wrote:
TimJ wrote:It doesn't make a difference to the flywheel but it does for the release bearing.
It doesnt make a difference to the bearing either, here is a list of all the cars/engines the standard bearing is fitted to -

http://www.realoem.com/bmw/partxref.do? ... showeur=on

But when you're fitting a collection of parts that are not used together as standard the original fitment isn't necessarily correct.

The bearing that I listed is longer to help make up for the fitting of a thinner flywheel. It's isn't absolutely necessary but I do believe it is the best solution (at least for a ZF320 with m20 flywheel, and the Getrag 250 seems to be the same).

I don't want to start an argument, this is just what I have found.

Post Tue Mar 19, 2013 8:38 am

When you have a thicker flywheel, you usually have a thinner clutch cover, therefore the bearing will remain the same height. Ive only ever had to fit a taller release bearing to one gearbox and thats the E46 6 speed I have on my own car.

Have you ever had problems with this yourself? Plenty of forums state that you must fit the taller bearing but its rarely needed.

Post Tue Mar 19, 2013 2:12 pm

^^ Yes I remember when I did mine putting the two side by side and the difference in thickness was almost completely taken up by the 'taller' clutch cover on the M20 clutch.

Had a prob on mine trying to use an M20 slave cylinder with an M50 box, the rod isn't long enough, but that's nothing do do with the release bearing thickness it's just different slave cylinders for the different boxes. I think maybe a few people have been confused by this and ended up fixing it with the release bearing rather than just getting the right cylinder.

Post Tue Mar 19, 2013 5:09 pm

Ive not long bought a new 328i slave cylinder for it and a goodridge braided hose

.
Offered up my E30 M3 prop up to gear box and its too big, was just goin to get a zf box but as I have the getrag I thought I may as well just use it as it is meant to be pretty much same as zf.
Will e30 325i selector rods fit?
Going to price up a 323i release bearing from ECP