M30 swap checklist

[More&Faster]

i've searched and done a lot of reading on this forum about the m30 swap in the past couple days. good stuff. my need to do this swap just go accelerated by about 6 months today because i twisted off my oil drain bolt while trying to put in thicker oil to try to get a few more months out of the m20.

long story short, i'm looking to buy an M30 within the next two weeks. i need to know what to buy and what i need to change.

1: i can keep the getrag 260 right? can i keep it in place without moving it assuming i fabricate my own engine mounts?

2: i know i can keep my stock wiring harness and just lengthen some wires, but i need the m30 ecu right?

3: can i keep my stock diff for now or should i change it, and if i need to change to the big case diff, do i need the axles too?

4: what year/model cars should i aim for? what's the best and what should be avoided. right now im looking at a 1990 735 for $500...can probably bargain down

5: is there any other serious issue i'm leaving out here? im thinking of just buying just an engine straight from a junkyard and going from there.

6: any good tutorial i could use for reference? i need one :)


thanks much for any help. i'm not totally clueless here as i've done some reading and have had my engine out before. just need some specifics cleared up.

[86espowa]

Buy the whole car with the M30 in it and part it out so you can get some money back from your engine build.

[mode]

Your 260 wont work.

[More&Faster]

Your 260 wont work.

is it a different bolt pattern or what? i've seen several people here claiming they use it.

[euroshark]

Anyone who used the 260 used the 260/5 or 260/6 from the 533i/633i or 535i/635CSi. The 260 that bolts up to the M20 will most certainly not work.

You do need the M30 ECU.

No motors are bad, it's the wiring that you want to focus on. Any year can work, but some are more "plug and play" - I say be a man and wire it all yourself, with electrical tape and man sweat. ... And solder.

[More&Faster]

Anyone who used the 260 used the 260/5 or 260/6 from the 533i/633i or 535i/635CSi. The 260 that bolts up to the M20 will most certainly not work.

You do need the M30 ECU.

No motors are bad, it's the wiring that you want to focus on. Any year can work, but some are more "plug and play" - I say be a man and wire it all yourself, with electrical tape and man sweat. ... And solder.

excellent post. thank you very much :bow:

[euroshark]

No problem. There is definitely a lot of conflicting info on the net regarding this swap, so if you have any more questions definitely ask those of us who have done it personally. Heck, PM me if you want.

[Funkmasta]

The confusing part is the Getrag made 2 versions of the 260, one that bolts to the baby 6 and one that bolts to the big 6.

Starting with the late model motor has its advantages... correct oil pan, more powerful motor, more clearance on the cylinder head... it is just really hard to find a m30b35 with a manual trans attached