Engine Swap ?????

[1990e30coupe]

Ok, To start- I own an 1990 e34 with an m20b25 it just rolled to 280k miles and will not run now. I pulled the head and found it has a valve issue and that the cylinder walls are scored; therefore, get a different motor. Well I happen to have a m20b25 with 59k but I don't want to waste it on an e34 so I found another car to buy, which is an 1987 325e. for a great price. Now I know there is a compression difference, but I want to swap the eta motor into the 525i and put the m20b25 out of an 89 325i into the 87 e30. I know everything swaps I have worked on them for years, which is funny because the only thing I don't know is if the brains have to be changed or will an "I" brain run a "eta" motor and visa versa? Never ran into this being an issue till know so I know there is still a ton to learn Need HELP trying to buy car tomorrow!
Common sense say if the compression is different fuel ratio will be different, but for all I know I could just do the engine swap and not have to mess with anything else.
Also if I just unplug the motronic system and plug it into the other car will that work or can I just swap motors and be done with it.

[Cabriolet]

I just did this swap for a guy.
you will need the engine, trans, diff, shift linkage, entire cooling system, starter, entire exhaust system, O2 sensor, and engine harness.
you MUST clip one wire or you will fry the harness.
coming out of the fuse box. there is a C101 connector. take the back rubber off and clip the brown wire on pin #20.

if you have all the stuff it's a 1 day job.

you will also need to attach 2 wires under the dash to get the tach to work

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

[1990e30coupe]

I just did this swap for a guy.
you will need the engine, trans, diff, shift linkage, entire cooling system, starter, entire exhaust system, O2 sensor, and engine harness.
you MUST clip one wire or you will fry the harness.
coming out of the fuse box. there is a C101 connector. take the back rubber off and clip the brown wire on pin #20.

if you have all the stuff it's a 1 day job.

you will also need to attach 2 wires under the dash to get the tach to work
http://www.strictlyeta.net/technical...onversion.html

This for putting an I m20b25 engine into an 325e I take it
And thanks for replying

[Cabriolet]

This for putting an I m20b25 engine into an 325e I take it
And thanks for replying

ya E -> I swap

[1990e30coupe]

ya E -> I swap

thanks for the link to the page I read it, great detail. What I didn't gather is if I can use the cooling system (radiator/hoses) out of the 325e with the I motor and the drive line. From reading that write up I assume he used the same cooling system that was already in the car.
See I bought the new motor with the tranny and thats all I have so I have to track down a harness, but I do have my 1990 525i for parts, so since its a m20b25 can I steal the Motronic Unit from it and just get a harness from an "I" e30? unless I can get a unit wherever I get the harness from (which will be the best bet. But if I have it use it!

Man I know I sound like I don't know anything but I have never had to deal with an eta e30 but I know the "I's" like the back of my hand. Really I guess I should ask questions after I open the hood on hopefully my new eta E30.
What's even more ridiculous is that I know how to build a turbo monster E30 and yet I don't know something like this.
Anyways, just comes to show there is always something more to learn!!! shocks me how different they are!

[Cabriolet]

oh i forgot to mention you will need an oil cooler from an 87 325i.

the late model cooling is worth the effort.
you need the I harness. else nothing will work.

just read the stuff on that page and the rest of the info he has. and follow it to the T. after you do the job. it will feel hella easy.

[jlevie]

This will be a hard swap. The M20B27 engine requires a different AFM, engine harness, and DME. But the kicker is that the transmission bell housing must have two ports for the ETA timing sensors.

Having said that you could turn the M20B27 engine into a budget stroker by using the AFM, head, intake, throttle body, injectors, FPR, CPS, engine harness, and DME from an M20B25.

[1990e30coupe]

This will be a hard swap. The M20B27 engine requires a different AFM, engine harness, and DME. But the kicker is that the transmission bell housing must have two ports for the ETA timing sensors.

Having said that you could turn the M20B27 engine into a budget stroker by using the AFM, head, intake, throttle body, injectors, FPR, CPS, engine harness, and DME from an M20B25.

So I have a 1990 325i tranny bolted to a 1988 325i motor, what tranny do I need that has two ports for the eta timing sensors. The motor is being stored so I am not around it to look.