Eta to I M20 Swap

[Low Level E30]

Say you're starting w/ a pre-'88 Eta (so a non-Super Eta)...

... what parts do you need to swap that motor out for a standard M20B25 I motor?

I'm assuming all the accessories are the same --- so what is different? I know a couple of things (intake manifold, diff, etc) but I'd like a comprehensive list from someone who really knows.

Thanks!

[mcgrath]

very simple. What you need:

1. The entire engine with accessories and full engine harness with ecu.
2. Enlarge the hole in the firewall where the engine harness plug goes through to the ecu (Motronic 1.1-1.3 has a larger plug)
3. Get wiring diagrams for the c101 plugs. One for the plug year on the car and one for the plug year of the engine harness.
4. Modify your existing c101 plugs or make a type of patch cable so you don't have to hack up either harness.
5. Depending on the year you may have to re-wire your C104 plug in the glove box ( I had to on my 85) For the wiring you should be able to find what you need here on R3v.

If you are swaping in an engine from an e30 that had the coolant resivor on the driver side then you will either need to take the entire coolant system from the donar car, or swap the whole thermostat housing from your old engine. Also if you do that then get a new water pump for the same year as the old engine so the hoses get routed correctly.

You can use your existing transmission just pull the crank sensors out off the bell housing and plug the holes or do what I did and just leave them in there.

If you can, get the full exhaust from the donar car or at the very least get the exhaust manifolds. They are a direct bolt on to the eta down pipes and are much bigger, better flowing than the eta manifolds.

Hope this helps.

[Low Level E30]

Great info, thank you!!

The i motor going into the Eta will probably come out of an '89 325i donor, which will receive an M50...

Lotsa swappage 8)

[MR 325]

http://www.strictlyeta.net/technical/engineconversion.html

[Low Level E30]

Sweet, thank you!