DIY M20 flywheel conversion

[KenC]

Just as an FYI, you can use a late model 325 starter instead of swapping out the gears.

[KenC]

Has anyone had issues with the starter slipping on the flywheel?  I think mine may be misaligned.

[razbok]

Hi there,

Gathering the parts to do this conversion on my E36 325i, but I've got a few questions for you guys:

Looking up replacement clutch kits, the 320i clutch kit for the cabriolet has the same part number as the 325i... and the 323i and the M3!   So I'm guessing that all these clutches will be fine when doing the conversion? As long as it's 228mm??

So does this also mean that any of these release bearings can be used??

I have the M20 flywheel that will foul the block but as I'm not using it on an M42, I wont have the spacer that is required so I was going to modify the block and sump instead... or skim the flywheel (I've not decided whether I can afford to do the latter), but will this not affect the conversion yet again because of the extra length the release bearing will have to travel?

Will the slave cylinder be able to compensate this travel?

I have a 1990 Starter motor from an E30 320i touring, I've read on here that I can use a 'late' E30 325i starter.    But if all M20 flywheels are the same, then surely any starter from an E30 with an M20 engine will work??? The bellhousing pattern hasn't changed. I think the E36s just has a locating dowel where the E30 doesn't...

I'm thinking the only way to do it is to get the box out and messure the distance from the block to the prongs on the flywheel of both dual and single mass setups and then the distance from the end of the release bearing guide tube to the point where each release bearing will contact the prongs.

Maybe then you could use washers behind the fork pivot to guarantee the correct spacing as the pivots' 'shaft' is quite long.

Also, can anyone tell me how thick the flywheel spacer is (roughly)?

Thanks

Raz

[Jimmy Lewis]

Wait what are you doing? What about an E36 325i? I do not understand why you are discussing using E30 components. I'm very confused, you want to to use a M20 flywheel with a M50 clutch, behind an M50, attached to a zf, huh? Whats so wrong with just using an M50 single mass. Explain yourself.

[razbok]

Wait what are you doing?

Trying to figure out what I need to convert my dual mass flywheel into a single mass

What about an E36 325i?

I have one.

I do not understand why you are discussing using E30 components.

I plan to use them

I'm very confused, you want to to use a M20 flywheel with a M50 clutch, behind an M50, attached to a zf, huh? Whats so wrong with just using an M50 single mass. Explain yourself.

What M50 single mass? M50s use a dual mass with an unsprung friction plate, like most E36s, including ones with the M42 engine.........
I never mentioned a ZF, I have a Getrag. Cant use M50 clutch with M20 flywheel... are you drunk?

:cool:

[gas axe]

How much of a difference does this make? I need to change my throw out bearing and guess this conversion could be performed at the same time. Will it spin into 2nd easily and make a noticeable difference to acceleration

[Asserti]

Can anyone confirm if this flywheel (the left one) is a single mass one?



thanks in advance!

[e30guydownunder]

I did this on my track car and had no end of dramas......you can't bolt a 323i starter (325i might be different) on as it hits the block and causes misalignment. I didn't buy a 323i TO bearing just used the one that came with my single mass flywheel clutch kit, which was exactly the same as my M42 TO bearing. And i used an '84 323i flywheel (2 kilo's lighter than the 325i flywheel and later 323i flywheels.

I also had to put the 323i starter pinion in the M42 starter and to do this i had to shorten the bendix side of the pinion by about 10mm and cut a new circlip groove in...I am unsure if this is a 323i related issue or something to do with all m20 starter motors.

So in summary:

3mm spacer between crank and flywheel
'84 323i Flywheel
'84 323i Starter motor pinion modded to fit in M42 starter
Shorter flywheel bolts
Single Mass m20 Clutch kit including TO bearing.

As a precaution i modified the clutch fork pivot point to make it adjustable incase there were issues with the shorter TO bearing. At the standard pivot height/depth there are no issues with (dis)engaging the clutch.

The engine revs a hell of a lot better and has woken up alot....i can't comment on noise because if there is any chattering it blends in with the rest of the noises....i removed all of the insulation on my car

Good luck to anyone looking to do this.

[Formulatwo]

You can do this swap WITHOUT the use of a e21 323i throw-out bearing.  

I did the swap and am using:

325i starter
325i Single mass Flywheel (Lightened to 11lbs)
325i Sachs clutch kit
325i throw-out bearing.

[harvey2]

You can do this swap WITHOUT the use of a e21 323i throw-out bearing.  

I did the swap and am using:

325i starter
325i Single mass Flywheel (Lightened to 11lbs)
325i Sachs clutch kit
325i throw-out bearing.

After going to the trouble of buying the E21 TOB for my conversion, I took the whole installation job to a local shop.  They told me that they would have compensated for a shorter TOB by adjusting the rod length on the slave cylinder,  as they have done for many different clutch conversion projects.  So, that's another way of skinning the cat if needed.

[thebutcher37]

Thanks!!! Formulatwo, and harvey2... whats with the 2's(two) Related??.. JK JK

Back on topic..

Its nice to hear a straight answer and list from someone who has it done....

I've been meaning to do this, and never had a definite list.

[harvey2]

Thanks!!! Formulatwo, and harvey2... whats with the 2's(two) Related??.. JK JK

Back on topic..

Its nice to hear a straight answer and list from someone who has it done....

I've been meaning to do this, and never had a definite list.

No prob.  If you haven't seen my list it is #42 in this thread:
http://www.m42club.com/forums/showthread.php?t=5696&page=2

[Formulatwo]

Here is a picture of the difference in the flywheel with the pressure plates...  The m20 unit is on the right.  You can see that it is smaller.  I measured around 3/8 of an inch difference in the two.  And like I said... I used a 325i throw out bearing for my swap and it's still working perfectly...

[Appletree IS supercharged]

I also had to put the 323i starter pinion in the M42 starter and to do this i had to shorten the bendix side of the pinion by about 10mm and cut a new circlip groove in...I am unsure if this is a 323i related issue or something to do with all m20 starter motors.

So in summary:

3mm spacer between crank and flywheel
'84 323i Flywheel
'84 323i Starter motor pinion modded to fit in M42 starter
Shorter flywheel bolts
Single Mass m20 Clutch kit including TO bearing.

.

I did the same, didnt take long to turn down and machine the new grove for the circlip thing in the pinion gear and works great now, however i did use the e21 TO bearing:D

i Also didn't use the 3mm spacer behind the flywheel, it seamed to mesh up all alright and didnt catch the block in anyway

[Bracky]

I think alot of people are getting confused about the references to 323's which is E21 not E30 version which as far as i know is a detuned 325i (still 2.5L) and should still have the same part numbers for flywheel parts and starter. E30 325i flywheel weighs about 19lb's and a E21 323i is 13lb's. changing the pinion is a pig and would not advise anyone to do it because of the amout of problems some people have had with it so on the setup im fitting in the next week im using a later 323i which many say is will be a direct fit, should make things a little more fun and i must point out that even with the 19lb 325i unit used in my last conversion it was well worth it and have no idea why BMW didn't make it this way in the first place.