bmwe21.net forums

Hi,
I have an '82 315, as far as m10 engine swaps go, do they all bolt in?
Original plan was to go for a 2.0 block out of an '02 or e21 320, but from the little research I can find, there are some external differences?
From what I found m10 1980 -> are the same?
So a E30 318i engine should bolt in, but a 70's 02/320 motor won't.

In saying that, are the only differences the motor mounts/mount arms? If so, are these interchangeable?

Thanks

To fit the E30 motor into the E21 you'll need to use an E21 sump pan, otherwise it fouls. You'll need to use E21 engine mounts too as the E30 ones are slightly different iirc, but both of these are straightforward swaps.

If you want to use the injection stuff, you'll also need to make a bracket to mount the AFM and install a return fuel line and in tank E30 pump (along with mounting the ECU in the glovebox and splicing into the loom). If you go this route, you'll probably need to relocate the battery to the boot as there isn't enough room for both that and the AFM. Your fuel needle will also show 1/4 full at empty - but the low level indicator light will still work.

There's probably some other stuff which I'm forgetting too, but there are a few threads on the topic if you use the search feature.

Won't go injection. Plan is m10 + sidedraughts.
Do the E21 or 02 blocks bolt into a 80+ M10 e21?

The pre 1977 e21 and 2002 blocks have a different bolt pattern for the RHD drivers side engine mount. You can either buy a pre 1977 e21 mount or alternatively swap the 2002 internals into a post 1977 e21 block, which I ended up doing with mine. Either way it'll then bolt straight in. Also, when you swap your new engine in, don't forget to check the little bearing in the back of the crank shaft, mine turned out to be knackered and has been grumbling ever since the swap!