a bit of clarification on M20 flywheel/clutch conversion

[ForcedFirebird]

I ground the oil pan bots to clear the m20 FW, no spacers and didn't have any issues with the slave not extending enough. Also didn't use the 323 TOB.

I know your pain. We spent a whole weekend trying to put a g260 behind the m42, all the online info was dead wrong. They said to use a 325i drive shaft but the splines for the two halves only engaged a tiny bit. Ended up finding a used g240 and left the m20 clutch parts in it.

[irish44j]

excellent, thanks. So in summary:

- don't modify the flywheel at all
- use the spacer off the M42 flywheel (the one with the rivets holding it in)
- get new M20 flywheel bolts (was going to do that anyways)
- use M20 starter as-is with no modifications
- use 323i TOB
- use all the rest stock M42 stuff (slave cyl, etc)

all correct?

[Dj Buttchug]

Buy M20 flywheel bolts for an M20 equipped with the single mass flywheel. Get new ones, don't try to find bargain ones at the hardware store. They are critical fasteners.

Use the spacer ring from the M42 flywheel between the crank and M20 flywheel. The pressure plate might not disengage properly without it since the slave cylinder has to push further. Don't machine the flywheel, unless you know a reputable shop that is known to do a good flywheel lightening job and can balance it up to at least 8000RPM.

I don't know if the M20 starter unit will fit the G240 bellhousing. All you really need is the pinion gear & planetary gear assembly from the M20 starter. Those can be installed into an M42 starter pretty easily. You will need to do that if the entire M20 unit does not fit.

this
and this

It will ;)

both are correct

[atmobenzin]

I don't know if the M20 starter unit will fit the G240 bellhousing

It will ;)

[bmwman91]

Buy M20 flywheel bolts for an M20 equipped with the single mass flywheel. Get new ones, don't try to find bargain ones at the hardware store. They are critical fasteners.

Use the spacer ring from the M42 flywheel between the crank and M20 flywheel. The pressure plate might not disengage properly without it since the slave cylinder has to push further. Don't machine the flywheel, unless you know a reputable shop that is known to do a good flywheel lightening job and can balance it up to at least 8000RPM.

I don't know if the M20 starter unit will fit the G240 bellhousing. All you really need is the pinion gear & planetary gear assembly from the M20 starter. Those can be installed into an M42 starter pretty easily. You will need to do that if the entire M20 unit does not fit.

[irish44j]

EDIT: Skip to post #13 for the DEFINITIVE ANSWER to the question of "what parts to use and what fits" for the M20 flywheel/clutch conversion on the M42.

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I managed to come by for cheap all the parts for the M20 conversion from someone who was going to do it but then did an engine swap and didn't need to. It includes:

M20 single-mass flywheel
M20 clutch and pressure plate (new)
323i throwout bearing
M20 starter (new)

So....all of the threads on this are so freaking convoluted with BS (I've read all of them at this point), just figured I'd ask a simple question to get a simple answer, hopefully.

With the above parts, all I need to do is:

1. get shorter flywheel bolts
2. machine the engine side of the flyweel a bit to clear the sump bolts
3. use the M20 starter as-is.
4. do NOT use the spacer off the M42 flywheel

Is that correct, or am I missing something?

thx,
Josh