Member
So I have a 1985 318i and the motor died while I was messing around with my buddies and now won't start only backfires and smokes out of the exhaust so I don't know what's wrong with it but I have decided that if it's a motor I would like to swap to something different, and in my area for sale is a 325 with no title but running and driving and the other option as of now is a m42 with 2 transmissions. My car is a factory auto and so is the 325 but the m42 comes with 2 manuals which I would prefer but I want to know the pros and cons of both swaps and what complications the manual would add.
Sent from my SM-G935V using Tapatalk
paper mechanic
after the m10 either would be an upgrade in power. i didn't know there even was an m10 auto version. just be aware that the front subframe for the m10 is different from the sub used for the later engines. you will need to swap the sub out as well or fab up some custom mounts. also a good idea to grab the rear trailing arms from the newer car to upgrade from rear drum to disc brakes. either engine will need the trans that comes with it as the m10 auto isn't gonna bolt to anything else.
Member
THere is nothing different about the early 318i m10 subframe from the m40/m20 other than a small little tab on passenger side for an engine shock absorber. This can be ignored and does not require changing a subframe at all.
The easiest swap would obviously be to drop in another m10, maybe have it go over with new gaskets and rod bearings while it's out So you don't have to worry about that for a long time .
Auto to manual swaps have been done many times and aren't rocket science , get the pedals , and donor driveshaft and keep in mind your 318i has small rear diff so it would make sense to swap the whole rear end to gain medium size diff and disc brakes .
Anything else would require a lot more work, driveshaft , exhaust , wiring , cooling system are all different .
I've gone through m10 to m10 to m52 to m30 and now to m60, the front subframe is fine .
Changing the rear end to disc brakes is very straight forward . Pull the rear subframe / diff / trailing arms form the parts car with disc brakes and swap it .
Last edited by 84318i; 01-16-2018 at 11:38 AM.
paper mechanic
srs, damn. lived under the impression they had different subs like the e21. i always wondered why the part numbers were different for the m10 only. that silly engine brace.Originally Posted by 84318i
Member
Okay well here's a new factor in the equation the parts car sold but there's a old 5 series at a local junk yard that has the 2.5l is it the same motor and trans wise or did that open a whole nother can of worms. If need be I know some one who can make custom drive shafts
Sent from my SM-G935V using Tapatalk
Member
Depends on the year, if you are talking about e34 Chassis they had m20b25 and m30b35 and m50nv and m50tu inline six engines .
All of these can be swapped into the e30, there are many complete guides and forum threads on this from folks that have done it before so you wouldn't be reinventing the wheel .
smooth operator
If you find an eta, its drop in. Change motor, trans, driveshaft, ecu and it will run. And use the eta wiring harness, of course, but it plugs in the early 318 cars perfectly.
I have done this swap on an 85 318 from an 86 or 87 325e. Plug and play
Member
Okay thanks guys
Sent from my SM-G935V using Tapatalk
Member
Also happens to be a m30 engine as well dad was out there yesterday and saw they had a e32 7 series again. I'm new to BMWs still so I don't know if that motor is better worse harder to swap or what.
Sent from my SM-G935V using Tapatalk
Member
M30b35 out of e32/e34 535i/735i is a good reliable engine to swap into the e30.
Check r3vlimited.com for a full section on the forum devoted to this swap.
You'll need custom engine arms to set the engine in the engine bay. Wiring harness can be out of manual or automatic car as the automatic trans in that era was separate and didn't interfere with the engine harness .
Manual trans you'll want to find out if the e28/e34 535i cars...e28 single mass 533 flywheel is a popular swap component .
The engine is long, so you'll need to fit an e28 radiator and electrical cooling fan as the clutch fan won't clear .
I've ran m30b35 for a couple of years , really reliable and simple engine but not very fuel efficient at all.
It's not a bolt in swap like the m20 for example or even a newer m50 Dohc would require less work in a way due to not needing custom engine arms and perhaps easier to find a manual trans for m20 and m50 vs m30 engine , they don't interchange .
Last edited by 84318i; 01-17-2018 at 04:42 PM.
trust the rust
I also have done an m30b35 swap. I grabbed the engine and 5-speed out of a manual 1988 735i, deleted A/C and was able to use the stock radiator. The only parts I needed other than the donor cars were engine mount arms and an electric fan after the stock one died.
I would say it's probably an easier swap than an m5x if you have a manual e32/e34 donor car. 84318i is right about the mileage though, I got around 13mpg city and 21 highway.
Member
What kind of power figures could I get out of an m30 with a little work
Sent from my SM-G935V using Tapatalk
trust the rust
Nothing that's worth it. The M30 is heavy and really tuned for low-end torque and it would just be a better idea to get an s50 or s52 if you want top-end power. Fun for daily city and highway driving though. The first thing I would have upgraded is the flywheel, it's just too heavy for an e30.
Posting Permissions
Reply With Quote
Bookmarks