1991 318iS M50 Build

[stormtrooper15]

Howdy R3V,

I have owned a 1991 318iS with the M42 for almost a year now and have been dying to swap the engine. I came across a great deal on an M50 so that's what I will be going with. I was reluctant to start a build thread due to my lack of being able to keep up the thread but I'll give it my best shot. The M50 came with a Getrag 250 (I believe), side reads Getrag 220.0.0225.96. I will have plenty of questions along the way, which I will research first and post here if I don't have any luck. I have E28 motor mounts, E34 oil setup, and red label 413 DME on the way so far. This will be my first swap so I'll be taking my time to make sure I have it all correct. The end goal is somewhere in the range of 300-400 whp (FI to come later).

Questions: 1. I have the opportunity to get a 5 speed ZF from a 2002 330ci. Will this work with the M50 in the E30 and what parts/fabrication would be needed? Would I be better off going for a 320 ZF?

[pazi88]

Yes the zf from e46 will fit. It's just regular 320zf. Same as in e36 328i/m3. You will need e36 328/m3 shifter assembly and driveshaft to make it fit. Other driveshafts like e30 324td one also fit.

[stormtrooper15]

Thanks Pazi! I’ll get the ZF. Has anyone tried using the 318iS throttle cable or just go E34 throttle cable? It’s only $35 but was just curious


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[raj]

Yes you will be better going with the ZF. Just make sure the detents are serviced and the seals are good. The ZF320 is generally regarded as a much stronger transmission than the Getrag 250.

[Mushroom Stew]

Just curious- is your 318 a 5 speed? Im doing the same swap as we speak and am keeping the getrag 240. Might save yourself a bit of hassle other than finding a 320i linkage for it.

[Codym42]

What rear diff are you using?

I just did an m52/ZF swap on my 318is.

[stormtrooper15]

My car is currently the M42 with G240 5 speed with 4.10 open. I’ll be swapping to M50 with ZF320 5 speed with ideally a 3.25 LSD. I don’t have the diff yet.


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[brads2002]

Just did this swap and pretty sure the 318 cable will fit. I had bought the e34 ahead of time so didn't actually try it but they seem very similar.

My e34 cable is all the way maxed to loose. It just fits. I wish I had tried the 318 before removing it and breaking the firewall clip.

[brads2002]

Just curious- is your 318 a 5 speed? Im doing the same swap as we speak and am keeping the getrag 240. Might save yourself a bit of hassle other than finding a 320i linkage for it.

Just FYI the 240 will not fit with the S52 clutch and flywheel. I found out the hard way. The bell housing isn't deep enough. I ended up going with a 260 thats been in the basement for years.

[stormtrooper15]

Just did this swap and pretty sure the 318 cable will fit. I had bought the e34 ahead of time so didn't actually try it but they seem very similar.

My e34 cable is all the way maxed to loose. It just fits. I wish I had tried the 318 before removing it and breaking the firewall clip.

I’ll give it a shot when I get to that point and let you know!


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[stormtrooper15]

Finally getting the rear brakes, wheel bearings, half shafts, and SS brake lines done. But ended the day stripping a hard line :/ anybody have a passenger side rear hard line for sale?


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[brads2002]

Last brake lines I ran I used the copper stuff. Real easy to work with and fairly inexpensive.

[Mushroom Stew]

Just FYI the 240 will not fit with the S52 clutch and flywheel. I found out the hard way. The bell housing isn't deep enough. I ended up going with a 260 thats been in the basement for years.

he's doing an m50 swap-same as me.

[brads2002]

Yeah, just figured the M50 had a similar profile flywheel. It wasn't even close with the s52 flywheel. Assuming he is using the 250 that came with it but where he is swapping into a 318is he probably has a 240 as well.

[AllydNYC]

What rear diff are you using?

I just did an m52/ZF swap on my 318is.

I used a 2.93 diff. For AZ's fast roads, it's a great. I would go for a low 3.xx LSD diff if highway driving wasn't as fast and we had more canyon roads.

Check out the Excel sheet here to find out the RPM @ speed with each diff and transmission configuration:

https://www.r3vlimited.com/board/showpost.php?p=2783454&postcount=6