m20b25 into my 318i

[318driver]

ok, so ive tried tons of things to fix my m10 motor and it doesnt look like its happening..... anyways..... i am able to get an m20 motor locally. The plan is to get the motor, get the head sent to the machine shop, and do the clutch then put it in my car.

questions? what things do i need and what prices should i expect?
fuelpumps?
radiator?
ecu?
wiring harness?
do i need to have the rear end from an m20 car? or can i run it for a while with my current rear end?
how much should the engine actually cost?
what is everything that is needed to be done i guess is what im asking?

[gstuning]

you need a 6cyl subframe to begin with,

you need to install a return line for the fuel, also a pickup pump the in tank and another one outside of it,

radiator and all that stuff needs to be from a 325i

[318driver]

are you sure about needing the 6 cyl subframe. I was told that id just need
m20 motor mounts not the subframe.

also an you elaborate the return line for the fuel?I know i have a fuel return linealread there from when i changed my fuel pumps and fpr.
the 318i has 2 fuel pumps, one in the tank and one out of the tank. can you elaborate on what exactly you mean?

[318driver]

also, i beleive the engine is coming from a 87.

will i need a different drive shaft?...

[mcgrath]

Engine, radiator, transmission, complete engine harness with ecu, drive shaft, rear end (differential). If you haven't done a rear disc brake conversion then now would be a good time. Just get the complete trailing arm assy with the E-brake cables they are 100% bolt on.

The sub frames are the same front and rear. it's all bolt on but you will have to wire up the C101 connector since the 318i has the rectangular plug and the 325i has a round plug. You will need wiring diagrams for both the 318i c101 and the 325 c101.

Realy in all it's very simple. Probably the easiest engine swap you can do aside from maybe an m42. There is plenty of information on this site if you dig deep enough using the search function.

Steven

[318driver]

well, right now i just need to get then engine in there and running. the basics.
was planning on doing the rear end swap for another day and just driving it with the stock rear end and brakes for now. Is that possible to put the 325i driveshaft to the current differenctial?

also where can i find the wiring diagrams?

[mcgrath]

yes the drive shaft will work, but from what I have read the small case diff can not handle the torque from an m20 and will pretty much explode if you run it hard, so I would suggest you baby it. As for the basics, what I listed off aside from the disc brakes is what you gotta have and you will wish you had disc brakes all around after adding that much weight.

here is the diagram for an 85 c101 it's actually for a 325e but I found that the 325e harness was a direct plug n play swap if it has the rectangular plug. You will notice your c101 has less wires due to the fact that you don't have the over head check panel.




This is the one I used for my 89 325i harness. It will have more stuff on it then an 87 harness but should help you out. I will look for an 87 specific harness when I get time.

[mcgrath]

here ya go 87 325i c101 wiring diagram. enjoy.

[318driver]

thanks alot, im really excited about doing this swap. glad that i have helpful forums like here and e30tech to help me get through it.

I have some confidence now and most of the parts available to me. Just gota wait till im done with school to pick em up and start doing it all. Then ill have more questions for you.

[318driver]

hey guys, it seems that ive jsut got a donnor parts car.

My car has a mechanical steering. Id like to switch it over to the power rack, but not have the power on it..... Anyways, will this be straight forward? old rack out, new rack in?

[ZiMMie]

^ Pm me a price for ur manual rack. ill be intrested in it.

[318driver]

whats so sougth after about it? ever drive one? Every dip and groove in the road it will pull you right too it. Very hard to autox it. my arms were tired afterwards lol.

Whats it worth?

[M20bmw318i]

pm me your email address and i have some more wiring diagrams. you only need a few wires to make the car run. i put a m20 out of a 1990 325i into a 84 318i. its not a hard swap at all.

[Garageaholic]

Mcgrath, That first picture was the c101 port, the second post you made was the diagnostic connector....

How did you get those diagrams?? do you have to subscribe to prostreet.com??

[e30_kid89]

hey guys whats up im also going to be going after this swap as well except i will be removing my m42......i was just wondering the the engine wireharness is it plug-n-play? or will i have to do any wire splicing some one let me know plz thanks