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which release bearing?
Posted: Wed Dec 02, 2009 11:57 pm
by baptie0
I am swapping the dual mass flywheel on my m50 for an m20 one
could anyone advise me which release bearing i require please?
also can i buy the plate and bearing separately?
thanks
Re: which release bearing?
Posted: Thu Dec 03, 2009 12:09 am
by Barx325i
e21 323 is the one for the m42 dual mass to m20 fly. I imagine it'll be the same story with the m50..

Re: which release bearing?
Posted: Thu Dec 03, 2009 6:48 pm
by Simon13
yeah but where the hell do you find a 323i release bearing?! theres none left
Re: which release bearing?
Posted: Thu Dec 03, 2009 9:41 pm
by DanThe
You can buy a bearing from the dealers, very expensive though, same story for a centre plate, approx £75 last time I enquired.
I will be asking a mate about a paddle plate for an M20 clutch in the next few weeks baptie, if I can get hold of some at the right money I will buy a few.
M20 release bearing works fine, if you wanted you could make the release fork slightly bigger by welding some strips on the contact area (which is what id do)
Re: which release bearing?
Posted: Thu Dec 03, 2009 10:03 pm
by Barx325i
migtastic, what sort of thickness doe these strips need to be Dan, I saw the two RB's side by side & the gap was quite big iirc. 4-5mm maybe more, but what would you recommend?
Re: which release bearing?
Posted: Thu Dec 03, 2009 10:43 pm
by baptie0
DanThe wrote:You can buy a bearing from the dealers, very expensive though, same story for a centre plate, approx £75 last time I enquired.
I will be asking a mate about a paddle plate for an M20 clutch in the next few weeks baptie, if I can get hold of some at the right money I will buy a few.
M20 release bearing works fine, if you wanted you could make the release fork slightly bigger by welding some strips on the contact area (which is what id do)
Yes I will do that too, is there much difference between the m20 bearing & the m50 type? also what are your thoughts on using the unsprung disk from the dual mass type clutch together with the m20 sachs cover?
Re: which release bearing?
Posted: Fri Dec 04, 2009 9:49 am
by DanThe
I was guessing at 5mm strips myself, M20 and M50 bearings are the same height.
Re: which release bearing?
Posted: Fri Dec 04, 2009 6:52 pm
by Simon13
Do you need to lighten the M20 flywheel also Dan for it to fit? I know i keep asking but i've got a good M20 clutch flywheel and a 328i with a seriously knackered clutch and probably flywheel.
Re: which release bearing?
Posted: Fri Dec 04, 2009 7:25 pm
by baptie0
if you remove a little bit of material from the sump then you dont need to have the flywheel machined/lightened.
Re: which release bearing?
Posted: Sat Dec 05, 2009 1:55 pm
by Barx325i
it is a nasty process though..
cheers Dan, ...I made this earlier - then thought I'd may as well make another, and ran out of wire

Re: which release bearing?
Posted: Sun Dec 06, 2009 6:50 pm
by Simon13
Barx how thick is that? 5mm? are they 2 feet off a M20 rocker or something?!
Re: which release bearing?
Posted: Sun Dec 06, 2009 7:09 pm
by Barx325i
it does look quite similar, no it was a surpless 4mm strip, the sort that you daren't throw away. I just hammered it a bit in the vice and then smoothed it off afterwards 5mm would have been a bit chunky I thought.. thanks again to dan, problem solved. it never occured to do this...
It's not perfect, but seing as I have 3 redundant m20 r.bearings, this uses one up.. and saves a far few quid

Re: which release bearing?
Posted: Sun Dec 06, 2009 7:21 pm
by DanThe
Looks just the job, id stick a bit more weld round it though, cant beat turning the welder up

Re: which release bearing?
Posted: Sun Dec 06, 2009 7:39 pm
by Barx325i
there is plenty on the insides, was filing back for a good while but I'll give it some more before it get's assembled.. I can swap the iS fly now, this was the only thing it needed.
Re: which release bearing?
Posted: Sun Dec 06, 2009 8:03 pm
by Simon13
hello?
Re: which release bearing?
Posted: Sun Dec 06, 2009 8:08 pm
by Barx325i
it's the same deal with putting an m20 fly on an iS afaik
Re: which release bearing?
Posted: Sun Dec 06, 2009 11:23 pm
by Simon13
i don't fiddle with 4 pots now!
Re: which release bearing?
Posted: Mon Dec 07, 2009 12:20 am
by Barx325i
I'm trying to break the habit but it keeps getting worse, I drive a 316 currently.. It will change soon.
Re: which release bearing?
Posted: Tue Jan 05, 2010 11:42 pm
by patrick85
I have a question. My M50 will not idle. It revs up and down between 400 and 1000 rpm for a few seconds and then dies. I have a flywheel and gearbox from an M42 on it. The flywheel is not a dualmass unit.
The car drives and revs perfectly. Just won't idle. Any of you have any ideas if this could be due to a flywheel that's too light. It ran perfect before the transplant and only things that changed are the flywheel and wiring and i've exhausted the wiring route. All is well there. Also doesn't matter if it's hot or cold.
Re: which release bearing?
Posted: Wed Mar 17, 2010 10:50 pm
by red318i
defo the flywheel, although im not expert and starting out with the long track of knowledge needed to swap an m50 in. only thing you could do is try raising the idle with your throttle pedal first to find a idling point. then adjust your throttle under the bonnet to suit, id say you would have to run at least 900-1000 rpm, but m50's sound nice idling at 900-1000 rpm any how!
dont forget your idle is set to have a nice huge dm flywheel keeping it smooth, you now dont have this and the engine is having a hard time locating the 500-600 rpm idle which is near impossible, i believe
but... im very happy to be corrected as id like to know the 100% correct answer to this as i may run in to this problem come my swap time
Re: which release bearing?
Posted: Wed Mar 17, 2010 11:06 pm
by DanThe
A straight 6 is one of the smoothest engines out there, losing weight off the flywheel will not alter the idle speed.
You do not adjust the idle on the throttle, or adjust it at all. Most idle problems on these are caused by air leaks
Re: which release bearing?
Posted: Wed Mar 17, 2010 11:15 pm
by Jhonno
My 5kg flywheel idles perfectly on my S50..
Sounds like an air leak
Re: which release bearing?
Posted: Thu Mar 18, 2010 4:37 pm
by red318i
lol there you go i was 100% wrong, dunno why i didn't suggest a air leak!!!