M10 to M42 Swap

[Trucidatio]

Well for a long time now I have been contemplating on which direction I want to go with my car, as far as drivetrain goes.

I have considered turbo, and my other thought is to swap in an M42.

I know just drop in an M20/ S5X/ M5X

But I would like to to keep the weight balance, and am really not looking for alot more HP.

Just reliabilty and better MPG.

So, my questions to everyone is.

Has anyone done this?
How hard was it?
Any idea on costs?

and I tries searching to no avail.

[Jean]

Well for starters you'll need the tranny as well, and exhaust system. Cooling system is different too. Wiring/ecu. Those are major ones. Probably isn't any more difficult than any other popular swap. Just make sure you get a low mileage m42 or you'll spend quite a bit on it's timing components.

[Trucidatio]

Thats what I was planning on doing, seems as though there are plenty getting unloaded everyday.

Exhaust isnt an issue, I have a friend who does great custom work.

What about the motor mount? Would I have to have those fabricated.

Really the main thing that scares me is electrical.

[Jean]

There shouldn't be any fabrication..just use the dohc arms/mounts.... m42 harness will not plug into the 84 318i chassis...you'll need to make an adapter but it's not complicated.

[Trucidatio]

Cool, this sounds doable.

As far as the cooling system, and other external pieces, mounting points will probably have to be fabbed up?

[Jean]

For what? The M42 will have it's own engine arms/mounts....and the subframe is not much different on the m10 (m10s have this little "damper/shock" that mounts to the subframe and engine on the passenger side) so it's pretty straight forward in that sense.

[Danny]

THEN turbo the M42.

[Jean]

Exactly, or that street legal supercharger. Otherwise I don't think it's worth the effort to replace the m10 with m42...

[Trucidatio]

The pieces i am reffering to as possibly haveing to make brackets would be the intake mounts, radiator, and other pieces along those lines.

I understand that the M42 isnt that much more HP gain over an M10, but thats to me really is not a big deal. I have a motorcycle for going fast. I jsut want that little bit so I can actually carry two bikes on my roof, and still be able to go on the freeway, also improved mpg.

[416stroker]

Just boost the m10.

[Trucidatio]

I dont really want a boosted engine, as fun as it would be, thats not really what im looking for. Unless someone has a full m10 boost kit, for the same cost as it would be to do an m42 swap, then deffinatly not.

[peete]

You will probably have to weld on a couple of minor mount studs for the intake system but you can work around that. Buy a CAI system and it should have the nessesary brackets.

I was seriously considering the M42 swap but there are so many M50/s50 swaps running around Atlanta, so I'm going to join the bandwagon. A couple years ago I turned down a complete M42 swap from the radiator to the 4.10 LSD for $800. Glad I did. Now I'm just trying to autoX to death my M10.

[Trucidatio]

damn, that would be an amazing deal. That is pretty much exactly what I would want to do. NA dfor $800, that is right in my price range.