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1976 BMW 530i e12

dhcomp

dhcomp

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I just purchased a 76 530i for a screaming deal!
Its in great shape, runs and drives well, cept it overheats.
Drove it about 2 miles before it started heating up, so i got it towed to my aunt/uncle's house.

Super clean paint/interior, 140k on the ticker.

Probably needs a head gasket, hopefully doesn't have a cracked head.

Going to tear into it next week, and see what i have. Should be a difficult first project, but if the head isnt' cracked, i think i can get it running for pretty cheap. Take a look!

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I was super close to buying a 75 e12. It was in that excellent green (mint-ish) color, and was in AWESOME shape. However, it was an Automatic, and I decided to pass. I still think about that car sometimes....

I think these cars have a reputation for a disastrous head. They apparently warp like crazy, and it is really hard to stop. The guy selling the one I was looking at had owned it forever, and went into the Cyclinder head thing in depth.

That being said, I am not far from you... if you ever decide to sell, look me up.
 
I will definitely keep that in mind.

I'm towing it back to where i live next week, and will tear into it. I have read nothign about the heads warping, on the 76 they crack before they warp i think. I'm hoping mine just needs a gasket, but if i need a head i'll either find a used one, or just sell it.

Can't wait to tear into it, and hopefully drive it one day!
 
Ok, so every sign of a head gasket or cracked head was not being seen.

I replaced the water pump, and figured out that the electric fan isnt' working.

I wired it straight to the battery, and it seems like its not over heating. New problem is that it is stumbling under load. Timing? Distributor?

I've never dealt with timing before, any advice?

Right now, it doesn't like to rev at all, sounds funny above like 3k. When i disconnect some wires that i think are the ign advance, it doesn't stumble, but still doesn't like to rev. When connected, it stumbles really bad when it should be advancing the timing.

How do i check into this?
 
Sounds like your timing is oof (I think you already had that figured). I have never actually worked on a 530, but I work on tons of VW Rabbits from similar years, and the FI is similar, I think.

My advice would be to check the timing marks on the cam gear, crank and the rotor. They need to all line up. If you get everything perfect, except are off one tooth on the cam sprocket, it would act like you describe (fine at idle, but bogs like crazy and has no juice when you rev it).
Good Luck!
 
I ordered the stuff to do a regular tune up, and need to go to my other house to get a timing light, so it won't be for a week or so.

How do i check what you described? Hopefully the mechanical advance is just screwed up...... or teh advance timing is not set.

thanks!
 
Do you have the manual for the car? They usually describe this in the procedure for changing the timing belt. THere are usually grooves/marks in a pulley that need to be lined up with either marks or divots on the engine some place.

I wish I knew that motor better to be able to help more.

-Dan
 
uggh e12 overheating problems:crazy: the true crux of e12 cars.

the overheating problems are usually caused by a lack of cooling system maintenance and usually the water pump is the first thing to go (the impeller acts as a sacrificial anode much like an outboard boat motor has) then the passageways inside the head go.

the early m30 engines (like yours) did have problems with cracking cylinder heads. if you end up going the head gasket route, and its an easy job, put the head from a later model engine that has the updated coolant passage design. Also, if you have the reactor exhaust manifolds (huge) still, ditch those to basically eliminate the cracked head problem. They hold huge amounts of heat in and that is what causes the head to crack.

you can direct swap in some from an euro spec e12 (try firstfives.org) or ones from an m30 powered e28 will also work but you may have to have the downpipes reworked to connect. (i've got a set from a euro 535i if you need some of those)


As far as the hesitation... check the air boot from the vane air meter (mass air meter to most) to the throttle body. if it gets cracks you'll get all kinds of weird stumbling, hesitation, and otherwise poor running conditions. it can also make the engine run lean and cause overheating problems.

secondly, check all vacuum lines. especially the seal around the oil dipstick, it is often overlooked and many times the source of a massive vacuum leak. These cars run under a crankcase vacuum system and a leak anywhere will cause problems (with the car idling pull the dipstick out or remove the oil fill cap, it stumble badly and should actually shut off. if there is no change in idle or a very minor change, start looking for vacuum leaks.)

the third place is in the vane air meter. take it off the car and turn it upside down. you'll see a plastic cover. carefully cut the rubber seal around its perimeter with a razor knife and use a flat screwdriver to open it up. look at the traces inside for deep wear marks. It the carbon trace gets worn through or thin in any spots, it will create all kinds of problems.


Also, since this is an l-jet car, do check the timing. it will most likely not be off but it is a good idea to check it.


hope this helps some and i'll be glad to offer any assistance i can.

I'm on the east coast (SC) but i do have 1 e12 and many e24 and e28 parts cars lying around that i can get things off of for you.

good luck with it,

al525i

1985 euro 525i m-reg

p.s. the funny sound thing is probably that the l-jet injectors are audibly loud and also the m30 is a solid lift cam engine so the valvetrain makes some noise. A valve adjustment would be a great idea for this motor and it is easy to do.

p.p.s get a bentley manual for the car. chilton is crap. it will be the best 50 bucks you ever spend on the car.
 
al, thanks a lot, that post had tons of good info!

So far, i have the hood off, and changed the water pump, flushed the coolant. I also figured out that the coolant temp sensor for the aux fan was shot, so that is on the way from bavauto. Once i changed the pump and got the fan running, it seems to not overheat, but it is without a hood right now. As far as the stumbling, when all wires are hooked up to the ign coil, it surges really bad above like 2000rpm's when under load. I'm hoping it just needs a good tuneup, and the timing set. I havent' even pulled the plugs, so who knows what tune up shape its in.

I have records of a valve train adjustment pretty recently, so not too worried about that. Once i take care of all the tune up stuff, i'll look into the stuff you mentioned if i still have problems. The air flow meter costs almost what i paid for the car, so hopefully i won't need one of those.

What exhuast manifolds fit that don't have the thermal reactor on them? I still have that hooked up.

Also, what is the top right pump on the front of the motor (drivers side)? It think its plumbed to the thermal reactor, so im guessing it is some sort of smog pump.

THanks for all your help!

darren
 
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