M30b35 swap: just a few questions.

[e30addict]

no shit it was that easy. no cutting wires or anything. just plug the 735 wire harness right into the c101 connection and she runs?

Yeah. I just pluged it in and it it started right up. I was amazed myself. The problems I ran into were money, and actually putting that big bastard in the car with the trans bolted to it. I invented new swear words when we did that.

[ttrousdell]

no shit it was that easy. no cutting wires or anything. just plug the 735 wire harness right into the c101 connection and she runs?

[e30addict]

Alright, here we are 1 year and 5 months later and I'm finally getting around to finishing this thing. Blame college classes and a full time job.

The engine is in and running fine. I have a few questions before I can get this thing on the road before it starts snowing and I have to put it back in the garage for the winter.

I used the engine harness from the 1988 735i and plugged the c101 straight to the chassis side c101 the e30. Car started and runs, no problem. The problem that I am running into is that my tach and temp gauges don't work.

I am a total electrical noob and I'm having a little trouble figuring this out. I have the electrical diagrams for the e30, but not for the 735i. Is there anyone that can tell me how to resolve these issues or start me in the right direction?

[LowR3V'in]

lol Y E S.

[yert315]

crank position sensor?

[LowR3V'in]

crank trigger

[yert315]

Ouch, tough luck with the m20.

I used the 325i harness in my b35.
Injector harness too. 100% 325i connectors.

Even using the 325i VR sensor.
Wire's just longer to reach the plug.

same here. I ended up rewiring the entire injector harness though.
what is a VR sensor?

[DLag]

Bookmarked* Good info on this thread. Hopefully I will be doing this swap soon..

[LowR3V'in]

Ouch, tough luck with the m20.

I used the 325i harness in my b35.
Injector harness too. 100% 325i connectors.

Even using the 325i VR sensor.
Wire's just longer to reach the plug.

[E30SPDFRK]

I got the 260 out of an e28.

You don't even need to modify anything then. The shifter sticks up in the factory hole and the e30 transmission support bolts right up.

[e30addict]

If the m30 harness is unmolested I'd use it, using the m20 harness requires a few wires to be extended which isn't such a big deal but it's your call really.

Do yourself a favour and buy a schrick cam for your m30, search alittle bit and you will find threads on people running them with good results. GL!

Just out of interest, how many valves/rockers did you bend/snap when your timing belt went on the m20?!

I snapped just one valve, but there was scarring on the tops of all the pistons and a hole in #4.

What gen 535i did you get the 260 from?

I got the 260 out of an e28.

[E30SPDFRK]

I'm 75% sure that you can use the engine harness that is in your car now and just plug it into the m30. I will be doing this in a few weeks for my friend so I will be able to fully confirm then. What gen 535i did you get the 260 from?


As for the cams, I have no idea. Ireland Engineering sells both a 284 and a 292 regrind though. They say that the 292 needs oversized eccentrics to work but the 284 works with stock parts.

[Doughnut]

If the m30 harness is unmolested I'd use it, using the m20 harness requires a few wires to be extended which isn't such a big deal but it's your call really.

Do yourself a favour and buy a schrick cam for your m30, search alittle bit and you will find threads on people running them with good results. GL!

Just out of interest, how many valves/rockers did you bend/snap when your timing belt went on the m20?!

[Miasma]

I am fairly sure it is plug and play, I recall someone using the M20 harness on a M30 swap.

[e30addict]

How 'bout just an answer to that first question?