Cylinder heads again:will a 535 head bolt up to a 530 Block

[canada karl]

i have been looking for a cyl head for my 76 530i. ii have an opportunity to buy an 81 3 series race car that has had a 535 motor installed in it. The car has suffered front end damage so is being sold off for less than the price of a new header. it may be worth my while to buy the whole car as I would gain a newer header as well as a cylinder head but I am unsure if the head would fit? I have read the Faq on cylinder heads but am not clear on a few things. first of all the engine is believed to be from a 535 but was installed by a previous owner so the current owner was a little unsure what it came out of but it is definitely an M30 six. any way to tell?Would this be a Motronic unit? I guess another option would be to instlall the entire motor into my 530i instead of just the cylinder head??? also the seller had a cyl head from a Six that had 74 stamped on the casting....had the early wide coolant slots .....would that fit on a 76 530i block?

[T.Hanson]

As a first vote, I've collected the idea M30 is a general block shape designator. The bore to be 2.8, 3.0, 3.3, 3.5 etc. I think the heads went through design changes with the cooling passages but all fit the blocks. With a correct head gasket.

Final answer. Before you truck anything home you may want to wait for a second, or the sound of a gong buzzer.

[John in Simi Valley]

i have an opportunity to buy an 81 3 series race car that has had a 535 motor installed in it.

Just a thought:
Put the 3.5L race car motor in your e12.

[canada karl]

T Hanson...I think your right about all the M30 heads fitting ....but I read something about later ones being designed for lower compression so wern't really suitable? I was hoping Mike W would chime in here before I gave it the gong. John....It occured to me to do that but apparently the car had been raced for six years! and I'm assuming driven hard?....the motor could be tired but the head useable? I wonder if there is any markings on the block or clues that would indicate the year? Maybe its even an Alpina clone????

[GripGreg]

The buzz is that the early head ('80 & back) has the larger coolant passeges so, this creates a tendency to over heat the head, 'cause the distance between the coolant passage & the piston wall in certain places is way too thin. And that tends to create a cracked head. All that to say that!
The stamp on the head that reads '81 & higher means the head was built with the corrected coolant passages. BMW learned a lesson.
But, all this may be a moot point in Canada, with your lower temperatures.
Good Luck,,,,Greg

[Mike W.]

T Hanson...I think your right about all the M30 heads fitting ....but I read something about later ones being designed for lower compression so wern't really suitable? I was hoping Mike W would chime in here before I gave it the gong. John....It occured to me to do that but apparently the car had been raced for six years! and I'm assuming driven hard?....the motor could be tired but the head useable? I wonder if there is any markings on the block or clues that would indicate the year? Maybe its even an Alpina clone????

Ding, Ding, Ding. Hey give me a chance to chime in, LOL.

Yes, all the heads will bolt up. Later heads off the B35 engine will lower the compression significantly, as in you don't want to do it. If it's motronic you would need the adapter nut, but it would work. The head gasket is only a problem on 3.5s, not on 2.8/3.0/3.3. Easiest way to probably determine if the engine (and head) is early or late is does the oil filter assembly face up or down? Up facing would be the late one, down the early one you would want. Unless you did use the whole engine.

[John in Simi Valley]

I guess another option would be to instlall the entire motor into my 530i instead of just the cylinder head???

Karl,
I agree the race car has been stressed at the track, no doubt.
I also know these engines are pretty robust.
Since you're not in the USA, the motor is more likely to be a Euro block.
The stronger M90 version, higher compression, bigger bore/shorter stroke for better revs.
If it's a motronic it'll have better engine management; more power and better mileage.

It may be that the motor is trash, but then again maybe not.
<i>IF IT WERE ME</i>, I'd have it checked, perhaps even rebuild it.
Previous racers may have some goodies in it worth keeping.

Best of Luck!

[canada karl]

There must be some way to identify the motor. The valve cover is black and it says Zunderforge or something similar on it???

[Mike W.]

There must be some way to identify the motor. The valve cover is black and it says Zunderforge or something similar on it???

Zunderforge is firing order, so it means nothing.

Often the S/N of the car it came out of is stamped on the flat back by the starter. Failing that, look on the exhaust side of the block, there will be some numbers cast into the block. That represents the date it was cast, emphatically not the production date. But it will give you some idea. It will be coded something like, and I may not even have the sequence right, but something like 21 A 85 That would mean the 21st day of January, 1985. There are lots of clues as to what it came out of, you just have to look.

[canada karl]

N/m

[John in Simi Valley]

When i was at Darwichian's place last month, we removed a cylinder head from a 633 with a 3.5 engine.
The front of the block had a distictive M90 in the front facing part of the casting.
I say distictive, maybe a centimeter in height, but it was there.
Darwichian said "this is an M90 head on an M30 block".

I'm no expert at identifying these engines, perhaps the MyE28 or Bigcoupe guys have the information you need.
I can check with some 'experts' for guidance if you like?

[canada karl]

Yes John..that would be great if you could do that. Here's a newbie question if there ever was one: how can you tell the difference between a motronic and an L-jet setup?

[canada karl]

Did you say" if the oil filter was facing down that is the early one you would want"?........I thought the early heads were the ones that cracked and the late ones were the better ones?

[thomas_m535i]

@Canana Karl: (1)Motronic is in many ways different from the L-jet. One easy way to tell is by e.g. looking at the intake manifold. Should be different.
(2)On my M90 (3.5L Euro 1980) engine, the oil filter assembly is indeed facing down.
(3) In terms of cracking: certainly no expert, but I believe that the cooling slots are different in terms of size for the early one's (<1980) compared to the later heads. As a consequence, these heads are more prone to crack. I think Mike W. has written some good info about it in the FAQ.
(4) The 3.5L Euro M90 engine's can be identified by indeed checking the front of the head for the text 'M90'. In addition, there should be a '3.5' and a big white 'L' stamped on the block itself. Also, the engine type '1270006' is on my block and near the starter your VIN should be mentioned.

I've some detailed pictures of my 3.5L Euro, so let me know if you need more info or pictures.

Thomas

[John in Simi Valley]

Darwichian wrote me back. He says when you remove the distributor cap (Motronic) the “M90” is on the cylinder head.

According to my Bosch Fuel Injection handbook, L-Jetronic and Motronic are the SAME with respect to the AFM, fuel injection computer and fuel system (sensors and components may evolve but philosophy is the same). The difference that Motronic brings is the modern electronic ignition – electronic spark advance, where L-Jet has the old style distributor – mechanical and vacuum spark advance. There are physical differences in the M30b28 (i.e; 1980 528i) engine and the basic M30b34 (i.e; 1986 535i). The Log and Rack-O-Ribs is replaced with a more efficient single piece plenum manifold is the most obvious difference.