m20 into blown 318is

[Chriskbmx]

ok so im about to buy another e30 to replace my freshlly rear ended e30. if everything works out with insurance i will be picking up a buddy of mines 318is with a blown m42. for 750. well for another 300 he will put in an i swap he has been collecting parts for. so i get a i motor with a 1.3 motronic and such and the g260 for 300 dollars. i just want to know what is all involved with the swap.

i kno the motor should just sit right in the bay.
but i am just not sure what goes on with the exhaust.
cooling? should i use an m20 rad or the m42 rad?
do i need to use the g260 transmission crossmember?
how about the drive shaft?
it already has a 373 lsd so we are good there. so im just wondering about wiring. as far as i kno im pretty sure its all plug and play. i just need to put in my dme?
i have an early model parts car. a 1986 325e.
can i use the drive shaft from that?

here is my other option. i can get an m42 with 89k for 800 with full harness and such. and sense im pulling out the blown m42 anyone that needs m42 accoreys hit me up lol. either way just thought id ask the pro's :razz:

[roguetoaster]

I don't see the point in M20 swapping a 318, M50, sure. Further, $800 is way too much for an M42, 89k miles aside, you ought to be able to get on for under $300. Save the headache and put an M42 back in or just get a car with an M20 to begin with.

[ButtJuice]

^


But I do believe the drive shaft is different, and the radiators too.

[Chriskbmx]

ok well if someone knows where i can sourse one in pa. ill lay cash out asap. and the only reason i would do the m20 is because it comes with an m20,g260,drive shaft and exhaust to swap

[roguetoaster]

Maybe just buy http://m42club.com/forums/showthread.php?t=15148? Sadly I could not find an M42 near you, so just post up a WTB, since people do seem very intent on x50 swapping every M42 in the US, so often they are just lying around taking up space in garages.

As far as an M20 swap you can keep the stock drive shaft IIRC adjustment should allow fitment. You can keep the M42 rad, but will need the M20 transmission cross member. Don't forget silly small things like the M20 coding plug on the cluster. Check to see if you need an M20 front sub frame, I think I read somewhere that they are different, but it may be just mounts. The exhaust from the M42 can probably be fabbed up to work, not sure on stock M20 exhaust diameter, but if its the same you should be fine.

Maybe ask in the M20 section too, unless you already have. Still, a lot of work is ahead, GL.

[Chriskbmx]

well i kno what it intales. wouldn't be my first swap lol. but i think im just gonna look for another m42

[flying_violin]

I know that iamcreepingdeath on the forums here did this swap in his car somewhat recently. Get in touch with him if you need.

[Ryann]

I don't see the point in M20 swapping a 318, M50, sure.

This.

[Chriskbmx]

yeah well there is alot work involved in an m50 or m20. and beside why do m50 for the few extra horses. just do an s50 at that point

[TobyB]

huh. really. m20 swap seems pretty easy and straightforward if'n ya gots all the parts...

m50 not much harder. but not as easy.

me, I like the m42... but like the m54 better.

[Chriskbmx]

yeah i get you. im looking at that swap but im also looking into making a 3.1 litter m20 but the m54 swap is probably cheaper

[iamsam]

All you knuckleheads who are telling this dude that an M20 swap is on the order of difficulty of an M50 swap obviously hasn't ever put an M20 in a 318is. It is literally just as easy as putting in another M42. The wiring harness round connector literally plugs in, not one wire needs to be relocated.

The only differences are you will need to buzz off the M42 rad mounts (on the car) for the M20 rad to fit (I used a pneumatic cutoff wheel), and you need to bring 12V to ONE pin on the M20 ecu for spark, and make sure you bypass the M20 relay function thing that cuts power to your blower motor and windows while the starter is cranking the engine, just one jumper in place of a relay, can't remember which one atm.

So in summary:
1. Cut off M42 rad mounts
2. 12V to one ECU pin (don't know which off the top of my head, but I can look at my car and get back to you if need be)
3. jump one relay (again, I can look on my car)
4. enjoy torque

Yes you need the M20 driveshaft, and engine/trans of course, ecu, radiator, and that's it.