M42 Swap Info Request

[CaseD]

Looking to do an M42 swap into '89 316i, and have no idea where to start

I've had a look for a write-up of some kind on this swap but can only find a few for 318, so wondering what differences there are to fitting into a 318. Ideally I'm looking for something with almost everything mentioned as I've never done anything like this before.

Also would like to know if there is any difference/preference between e30 and e36 m42.

Cheers guys.

[rix313]

Right

Your 316i is the same as the 318i bar the crank shaft (just though I'd clear that up ).

The E36 engines up to 1995 are the M42 (which are 1.8 ), post 1995 E36 engines are M44 (which are 1.9).

If you plan on fitting an E36 M42 you need to change the inlet manifold to the E30 one (E30 one is better than the E36 one), you will also need an E30 M42 sump and engine mounts. It's much easier to find and fit an E30 lump tbh.

You need:
1. M42 engine
2. M42 engine loom and ECU
3. M42 exhaust manifold
4. 318iS exhaust system
5. M42 coolant hoses

You should be able to leave the rest of the drive train alone as they use the same gearbox as the M40 (engine code for your 316i and the 318i) so I've been told any way lol! (having problems with mine but seem to be the only one ).

If you pull all ancilleries from your 316i out of the engine bay prior to lift it will make it all easier. You can reach all the gearbox bolts behind the engine and from under the car. You might like to try doing it by undoing the engine from the gearbox, pulling the engine forward and up then dropping the M42 in and back onto the gearbox although lining the two up could be fun! If you have a little more time take the M40 out with the gearbox attached, take the gearbox off and bolt it to the M42 then put the whole lot back in again, depends what you want to do, both have the same amount of faf involved. Doing the latter can be done in a day easily as long as you prep the engine which is coming out like I said (by disconnecting everything and making sure all bolts are loose so you don't waste time trying to undo tight bolts on swap day).

Bare in mind the 318iS (which came with the M42) came with rear disc brakes and you wont have them on the 316i. You might also want to upgrade the suspension.

Hope that helps.

[CaseD]

Thanks alot, cleared that up a treat, can get started now.

[Dave_M3]

318iS and 316i gearboxes are different but the 316/18i box will be fine with an M42 engine.

[GrindCulture]

If you plan on fitting an E36 M42 you need to change the inlet manifold to the E30 one (E30 one is better than the E36 one), you will also need an E30 M42 sump and engine mounts.

You can use the E36 inlet manifold, but the sump, pickup pipe, dipstick, crank pulleys, exhaust manifolds and mounts will need to be changed.

You'll also need to attach the individual coil pack bracket to the inside O/S wing when going from M40 to M42.

I also found that the M40 gearbox was not the same as the M42 gearbox I had fitted. One was slightly shorter than the other, although I can't remember which one. This could throw up problems with propshafts if you don't have the correct one to go with the gearbox that you're using.

[stonesie]

I also found that the M40 gearbox was not the same as the M42 gearbox I had fitted. One was slightly shorter than the other, although I can't remember which one. This could throw up problems with propshafts if you don't have the correct one to go with the gearbox that you're using.

If he keeps the cars origional box then all that can be avoided, 316/318 use the same gearbox and it should have had an easy life with 1.6 power, although i would replace the gearstick with a Z3 1.9 one and change all the bushes in the linkage