1985 318i M42 conversion

[1985_318i]

I'm sure there are posts on this, but I can't find them.



Okay, what all would I have to do to swap an M42 into my 1985 318i. I have a guy who is selling one cheap in my area with motor, ecu, and 5-speed. What all else will I NEED (driveshaft, etc)? I also have a rearend that is supposedly from a 325, it has an 8 bolt rear and 3.73s. Will this work without swapping driveshafts?

 

[epj3]

engine, transmission, driveshaft, and differential (differential only depending on ratio). More than likely that's it.

 

[1985_318i]

Will the factory diff (~3.56) on my 318 work? And if I keep this can I use my factory driveshaft?

 

[nadroj]

i would try to get the stock 4.10 diff if i was you, unless speed isnt a factor for you

 

[1985_318i]

i would try to get the stock 4.10 diff if i was you, unless speed isnt a factor for you

I would love to get it, but the guy is not willing to part with it. It is all in a 2002 and he is selling the M42 for an S14. I plan on getting it tomorrow or Tuesday. I just want to see how much modifying I am looking at having to do b/c I want to install it over Christmas break, if I can get it.

 

[Chesty Bonds]

Yeah I would def. get a 4.10 diff if you can. I think the open ones are fairly easy to source, but the LSD's are virtually impossible to get. The M42 needs revs to pull hard an you'll have to work it pretty hard with a 3.56 diff... It doesn't really have the power to pull that ratio.

 

[1985_318i]

Yeah I would def. get a 4.10 diff if you can. I think the open ones are fairly easy to source, but the LSD's are virtually impossible to get. The M42 needs revs to pull hard an you'll have to work it pretty hard with a 3.56 diff... It doesn't really have the power to pull that ratio.

The 3.56s will have to stay for awhile, I just want to make sure that the driveshaft on my car now will work with the M42 trans and my diff now, or a 325 diff with 3.73s that I have lying around. I currently don't really have the money to buy the engine and trans now, let alone a diff and/or driveshaft. (good thing I'm getting the ECU, harness, coil packs and everything else with it )

Also, I thought the M42 had more power than the M10 which is geared at 3.56, so shouldn't it be able to pull that ration without a problem?

 

[Chesty Bonds]

Also, I thought the M42 had more power than the M10 which is geared at 3.56, so shouldn't it be able to pull that ration without a problem?

Yeah it'll pull it but what I mean is that it won't pull it very well. With the M42 you need the gears stacked pretty closely to keep it on the boil so you can achieve maximum acceleration.

 

[ldzpstnr]

You will need to swap out the wiring harness and fuel injection also. The M42 has a newer fuel injection system while the M10 has a real basic one. Might need to change the fuelpump also.... but I am not sure about that one. The older E30's had two fuel pumps, one in tank and one outside the tank while the newer E30's only had one pump.

Good luck on your swap. It should be fun. Later.

Aaron