In Need of Help with 3.5L Swap into 71 Bav.

[Colorado S14]

I picked up a 71 Bavaria from an elderly neighbor earlier this summer. The car is in great shape with a beautiful interior and pretty good Polaris Silver exterior. I bought it knowing that there was some work to be done, he said that he had a bad headgasket and that needed replacing. Well after snagging it from him for a great price I started to do some research and just started to get the inkling that the head instead may be cracked. Well I finally got around to pulling the head off and taking it down to the machine shop and sure enough we've got ourselves a cracked head. So now rather than track down a new head I think I may just get myself a junkyard M30 out of a later BMW and drop that in.

Here are the questions that I have:
Is there a best year for these engine when it comes to swap cantidates? From what I have gathered the last revision came in the M30B35 which was after 1988?

I have read posts that have said that the manifolds bolt on to later motors regardless of year, is this the case? I would like to keep it as simple and somewhat period correct as possible so would like to keep the factory carbs if they will just swap over.

Do the bell housings match up for the manual transmission? What about flywheels and clutches, will I need to source those for the engine year?

What about external accessories? Will things like the alternator, etc. bolt up or do I need those off the new engine?

And finally...It appears that the engine mounts are different. Some reference Koala Motorsports adapters but they only list them for E24/28s, are those the ones? If Koala no longer makes them what are my options.

Thanks a ton, looking forward to getting rolling on this bad boy.

 

['yata]

I had a North American 1985 M30B34 installed in my 71 Bavaria. These have lower 8.0:1 compression and 185 hp and bolted directly to the Bav motor mounts. Beginning in 1988 the North American M30B35 had 9.0:1 compression and 211hp, but i believe these don't bolt up directly. To go with the dual carbs, which i also did, you have to use the distributor from the 71 which will requires a cam conversion nut (La Jolla Independent) that allows the original top mount shaft distributor to be used with the cam on the newer engine and you will need to retain the 71 valve cover and timing chain cover to accept that distributor. You'll need to get an electric fuel pump as the fuel injected engines do not have the set up for the mechanical pump. The transmission bolted directly to the engine, the engine i got was out of an automatic 735i so the flywheel from the original engine had to be installed along with a pilot bearing. We also reused the oil pan from the Bavaria along with the oil pump cause i think there was a clearance issue. The Bavaria exhaust manifolds bolted directly to the engine.

If the cylinders and walls look good in yours you might want to try and locate a Spanish cast M30 cylinder head...which has AMC cast into the side of the head instead of the year.
http://www.firstfives.org/faq/cylinder_head/cylinder_head_faq.htm

 

[Mike Goble]

I have a 1988 M30B35 motor in my Bav - went in on the stock mounts. Original intake and exhaust manifolds bolted right up, 265 5-speed, single mass flywheel and clutch bolted right up. As noted you will need a cam adapter nut and keep the original front cover and valve cover.
I used the lift pump bracket from an E24 to keep the stock VDO pump in the tank, and it fits perfectly, and the sender adapts to the stock wiring.
I used an E28 oil pan and pump, along with a top bolt oil filter. There is a hole in the oil filter cavity on the block that needs to be plugged in order to get oil pressure.
You might find that some accessory brackets are peculiar to the later engine, like the air conditioning compressor.
Depending on which flywheel you use, you may not have a BB in the right place to set your timing per the book. I recreated my marks on the damper on the front of the engine, like you see in most American cars, and set the total mechanical timing to 36°, then put my VA can directly to manifold vacuum. It's been in the car for about 5 years and has performed beautifully.

 

[chope97]

I have a 71 Bavaria w 3.3

The PO had a 3.3 from a 533i and 5 speed installed. It looks stock with Weber 32/36 DGAV carbs. This engine came out of a 533i E28 from 83-84. E28 3.3 and 3.5 engines should fit without problem.

 

[HB Chris]

An 88 has the proper passenger side motor mounts bosses on the block, later ones may not requiring the adapter, no big deal but check first. You need the early stock oil pan and oil pump pickup and dip stick tube. Plus dizzy style upper timing cover and early valve cover, later covers have an offset center front mounting hole. If using the b34 metal air cleaner the oil filler hole needs to be in back meaning you now need a valve cover with rear filler and centered front mount, early e12 I think and a bit harder to find.