320i motor into 318i?

[boostless]

Been looking for a new motor since mine has low compression on a cylinder. Will a M10 out of a 320i fit into my 318i?

[jlevie]

A 320i has an M20B20 engine, not an M10. It will fit, but the transmission will need to change to a Getrag 260.

[Rockwool2117]

hey boostless, welcome to r3v. i dont see why not, same engine right? on the older motor would have a carb . The 318i's m10 is desegnated m10b18 whereas the 320 is a m10b20.
this has more information http://www.r3vlimited.com/board/showthread.php?t=222636 according to the link motor mounts may differ

[boostless]

Good info, all the 2.0 blocks are the m10b20 correct?

[Holland]

From what I have read, all US spec E21's are M10 equipped. Only the euro market got the M20b20.

[hendrixvodu]

Euro e21 "323" had an m20b23 e21 320 was an m10b20 until 1980. 81-82 was an m10b18 all e21 320s were carb or cis so they were mechanical fuel injection with the use of a fuel distributor

[thebutterson]

I have an e21 motor in my car right now. It'll bolt up just fine using the same transmission and motor mounts. The only thing that didn't fit right was the splash shield for the transmission because the block didn't have the same bolt holes. It'll still bolt to the transmission though and stay in place just fine.

[TobyB]

Wait, what?

The earlier US E21 got an M10b20, the later (post '79-something) got an M10b18.

The M10B18 is dang near identical in the E21 and E30... same head, pistons, crank,
and the block's interchangible but a different casting- all the same bosses, just slightly
different gussets and a bit heavier.

Yup, we weighed a lot of M10 blocks over the years...

t

[irish44j]

If anyone is interested in an M10B20 (out of a '77 e21 320i), hit me up. I have one complete engine, turns fine though never started it (came in the 320i project car I just got and am engine-swapping). Located just outside D.C.....make an offer and come get it :)

[boostless]

Ok so I went ahead a took the plunge into this and the motor is in the car with no spark. I have the distributor from the 320 on there since the 318 spun the opposite direction. I splice the cable to fit the distributor. Is there something that I am over looking???

[thebutterson]

What I did was put a 1.8i head on the e21 block, so I never had to worry about it. The best thing to do now would be to swap the distributor gear from the 320i onto the 318i distributor and set it up as normal. Have you verified there is no spark, or does the car just not start? I'm not sure the l-jet will work correctly if it's not getting the rpm signal from the distributor.

[boostless]

That's what I was thinking is to swap gears after readin further through the Bentley. There is no spark coming off the coil, I tested by holding the wire to the strut mount looking for the arc.

[boostless]

Got it running today, had to swap the distributor gear and she was good to go. Now to get the hood on to go for a ride.

On the gear swap I drilled out one side to get rid of the "taper" to be able to punch it out. It's more like a squished rivet than any thing

[thebutterson]

Great! Always good to get another m10 e30 on the road. What part of WA do you live in?

[boostless]

I'm down on Lewis/McChord. I did take it out for a drive and it feels real sluggish like the cat is clogged, which it was fine before the swap. I do have get a timing light to set the timing though which I'm gonna try and snag tomorrow.