bmwe21.net forums

can someone point me to a good write up in detail in what parts req and how to fit an m50 engine ?

there's no official write up per se. theres only threads in the modified owners cars section - theres a fair bit of custom fabrication required.

It's well worth the effort though.

what gearbox is needed?

The manual one already attached to the m50 engine.
But m20b25 will be enough for getting tickets also!
And it is easier to swap than m50.

not a lover of the m20 engine - had too many and broken them all
what diffs are people using with m50? (with e21 box)
as im thinking e21 box would be easier to use due to speedo and prop etc (especially if i have to get a diff aswell)

thanx guys think i need to start sourcing parts over winter ....

project m50 ?

I can help you out with the custom parts if you want. Just makes it a bolt on job.

tell me more....

Ok firstly m50s are ok but very heavy engines. Go for an m52 and you will want the 2.8

sump required is from an e34. This can be used but it will hit the ground so I cut and modify it and add a wing on to keep up the capacity. It ends up level with the subframe.

You will need a rad. You could get a copper one done but really they are a bit... Meh. I use a genuine wrc forest spec core and the rad fits perfectly in the gap between the headlights.

The steering link you can flip the ends around.

Manifolds will need modification and a custom exhaust. The guy I use has a mandrel bender and uses tig / t304 stainless. Lifetime warranty.

Wiring. You probably won't need help with that.

On the m52 it's obd2 the ecu requires custom software otherwise the abs fault cut will kick in and limit your revs to 5.5k. The software I stick on is a remap for the m50 intake, no ews immobiliser as well.

brilliant info nas
e34 sump> 520 ok or does it have to be 525?
i was thinking one car as a donor but now im thinking thats not going to be the case.
is the radiator a mk2 escort item as seen on ebay?
as i found a few when i was looking for a rad for my m10 engine .
wirings ok im an auto electrician-
and yes id seen on the wiring for m52 it was linked to abs etc
didnt know if it was possible to use the m50 managemnet system but if the software can be doctored that will be better as i remember years ago i had a customer fit an m3 evo engine into his e36 320 and had all sorts of problems.

Yea you can use the m50 electronics but has to be from a vanos and you will need everything off the m50tu.

As long as the engine is an m50 out of the e34 all sumps are the same.

The rad is the same size as a mk1 but not the one on eBay I don't think? AH fabrications make them I get a discount and pass it on. They have to put different size ports and the filler neck is in a different place.

Wiring the engine is the most easiest bit of the whole lot really.

Grab a 318is in tank fuel pump from an e30. It goes straight in and has a built in return port.

ref gearbox
as it seems e21 boxes are becoming rare then alternative is to fit box from donor vehicle but-

has anyone managed to mate a 6 speed box to the m52 ? and if so what are the ratios like?

I put the zf on. But I run mine at stock angle the zf 6 speed will bolt in but it's longer so you still need a custom prop. The 5 speed zf has the same ratios as the e21 dogleg. Dunno about the 6speed. Probably the same but with an overdrive for 6th. Google will tell you.


Your only real problem is the lack of a Speedo drive. There are expensive ways of getting round that too.