Fitting a e36 zf 5 speed speed box to a m42 engine.

[E30318israce]

Hello. I have a 1990 318is tarmac racer I just bought and want to change the standard getrag 240 with overdrive for a e36 zf box with a 1:1 ratio on fith gear. I found out that the m42 getrag boxes shared the same bolt pattern as the m50 zf boxes.

I have the single mass m42 flywheel atm and a standard clutch, I dont want sinter clutch/paddle ect because of a low power limit in the class. (160whp maximum) But I want to change to a zf box so I can actually use the fifth gear and not only 2-3-4 gear as is at the moment. I can't find much info on about how to do the swap, wich clutch to use ect. I'm guessing the zf box for a e36 has a different clutch.
From the info I have found I'm aware that the box will be standing 10-15 degrees wrong and that I need to build a new propshaft.
Anybody in here done this type of swap?

Kind regards Amund, Norway

[DanThe]

The M50/M52 ZF box is the same angle as your iS so will sit perfectly, you can leave the flywheel clutch as is too. But there is also a smaller Getrag box with 1:1 5th gear found on E36/E46 318i cars which would be ideal for your car

[E30318israce]

Thanks for the reply, so the getrag 240 is box actually has the same spline on the input shaft as the m3 zf gearbox? That's amazing if so Another issue might be tunnel clearance? I am not allowed to weld in a new gearbox tunnel, but it might fit? I am supposed to get a e36 zf 328i/m3 box delivered next weekend so I'll go with that one. Should be pretty bullet proof as long as the syncro rings is good I guess.

[Brianmoooore]

One thing to check before you fit it is that the inner race in the spigot bearing matches the input shaft spigot in diameter.

[E30318israce]

Yes, the spigot bearing needs to be changed for a e36 one wich has a bigger inner diameter but luckily the same outer diameter and depth

[E30318israce]

The M50/M52 ZF box is the same angle as your iS so will sit perfectly, you can leave the flywheel clutch as is too. But there is also a smaller Getrag box with 1:1 5th gear found on E36/E46 318i cars which would be ideal for your car

Would that be the getrag 250 box? It has to come from 4 valve injection engine to have the same angle as the 240 box from the e30 is?

[Andyboy]

Getrag 250G. As fitted to the E36 316i, 318i and Ti, 320i and most 323i and 325i's.