engine and drivetrain Difference between M10 & M20 bellhousing

[tomorrowcalling]

Can gearboxes be changed between M20 & M10 engines or are the bellhousings different?

[merlin]

the bell housings are VERY different. A 1/4" or so thick adapter plate would have to be made up with spacers. We had to work around that problem when we did the 4 speed auto into andys wiges M10 powered 02.

sam

LaValle's Import Restorations.

[BarryA]

euro M20 powered E21's (320/6 and 323) - their 4 and 5 speed transmissions are essentially the same as those used in M10 powered cars, but the transmission case has the M20 bellhousing pattern. 4 speeds aren't too hard to find, but 5 speeds are getting really hard to come by - there weren't a huge number of 323's built in the first place, and they were never officially imported to the US.

The bellhousings are NOT removable, so the whole 6 cylinder transmission is required.

[canadamatt]

The bellhousings are NOT removable, so the whole 6 cylinder transmission is required.

Incorrect. e21 320i 5speed on the left, e21 323i 5speed bellhousing on the right. I swapped the euro bellhousing onto the 320i 5speed.

Matt

[MikeinNC]

I am planning that same swap over and was wondering if the E21 internals would fit since I have a 323 4 speed. You have answered my question even though you did not know I had it

Cheers

[canadamatt]

I am planning that same swap over and was wondering if the E21 internals would fit since I have a 323 4 speed. You have answered my question even though you did not know I had it

Cheers

More on that

- as stated above, 323 5spd bellhousing bolts up to 320i 5spd trans. No work required.

- 323 4spd bellhousing can be MADE to fit the 320i 5spd, but requires some machining of the bellhousing. This info came to me about 5 years ago from someone who did this as all they had was a 4speed bellhousing. So it works, just be aware that its not a straight bolt on. I'll see if I can find the old emails that specify exactly what needs to be machined.

hope that clarifies things

Matt

[tomorrowcalling]

So let me see if I've got this straight,

I know where I can get a close ratio five speed originally fitted to an M20 engine. I guess that would make it a getrag 245/11. I would like to fit it to the M10 engine in my 2002 rally car.

From previous posts am I correct in stating?

1 A 245/11 will not bolt directly to a M10 engine

2 If I find a getrag 240 I may be able swap the whole front casing between the two boxes?

[Rigmaster]

The bellhousings are NOT removable, so the whole 6 cylinder transmission is required.

Incorrect. e21 320i 5speed on the left, e21 323i 5speed bellhousing on the right. I swapped the euro bellhousing onto the 320i 5speed.

Matt

Uhh Matt, that's NOT the bellhousing in your pic- it's the whole damn tranny case!!!!

The bellhousing is just the front part, that covers the clutch/flywheel. MOST BMW tranny's do not have removeable bellhousings in the tradititional sense. Some Early E28 528e's have them, as well as the E30M3 and some others. The trick setup is the bellhousing from an early 528e, combined with an E30M30 gearbox, which allows you to bolt the CR M3 tranny to an M20 (still don't have a speedo drive for 2002 swap use, but.........).

Bret.

Bret.

[canadamatt]

Right you are Bret (obviously!). I don't know why I always call it a bellhousing...I guess it is..partially...but its part of the front case as you said. Anyways, what I was trying to get across is that you CAN frankenstein up a trans that will work.

In case anyone is interested in the effort involved, at the time I had the front case swapped, I didn't have the tools or time to do it, so I paid a shop...they charged me 2 hours labor. So I can't see it being that involved.

Matt