Firstfives.org

Hi,

i currently have '81 e12 with 2.8 ltr, 5 spd. Im looking to see if anybody knows if the m50 engine from the e34, e36 has ever been installed in this chassis? I would like to know what to expect, what kind of modifications would be needed to the suspension, engine bay. If anybody has any thoughts, or links, it would be greatly appreciated.

Rj

The short answer is, Yes. The longer answer is:

I was part of a build that put an S50 (externally identical to an M50) into a 1972 Bavaria (not mine). Granted, we used an E28 5er front subframe, but the following ideas are the same.

Engine mounts and exhaust manifolds will have to be fabricated. I'm not sure if the stock M50/S50 intake manifold will clear the brake booster in an E12 engine compartment; in an E3 it does not.

The wiring is the wiring. Use an OBD-I (up to 1995) harness to avoid the myriad sensors and pumps that come with OBD-II (1996 and later). The anti-theft system that runs through the ECU, called EWS, came online sometime in late 1994; it's way easier to use a pre-EWS ECU for either the M50 or S50.

You will want to use a 1982-only 528e bellhousing. This connects the engine to your Getrag 265 transmission. The latter, of course, allows you to keep your mechanical speedometer drive.

Piece of cake, right?