Interesting thought

[lepre003]

I recently had my transmission go out in my 91" 525i .. So for now I have to use my old pretty beaten 85' 735i. I got to thinking, if I am correct some early E34s have a M30 in them.. Is this the same M30 that is in my 735i? Would I be able to essentially swap the M30 and the transmission into my 525i? This is just a thought because I do love the M50 and it does run well, just curious and wondering what my options are.

[BoldUlysses]

Subframes are probably different (don't quote me on that).

The engine in the E23 is an M30B34. The E34's M30 was a M30B35. The overall engine and packaging is the same, but there are numerous detail differences, most prominently when it comes to engine management (Motronic 1.1 vs 1.3). You'd probably need a whole E34 M30 wiring harness and computer, and many of the sensor mounting points are probably different. Not to mention the fact that the B34 is about 20 hp down on the B35 (lower C/R).

So it's physically possible, but the details will kill you.

-Matt

[Binjammin]

It is NOT the same engine as the e23. The filter canister and sump are totally different, and the early engine will not physically fit in an e34 because of it. Later versions will swap into older cars, but not the other way 'round.

Subframes are different as well.