New owner with cracked cylinder head has a few questions.

metsfan3321 · Post by **metsfan3321** » Mon Sep 15, 2014 5:50 pm

Hello everyone. I am a proud new owner of a 1979 528i. I will upload pictures of this beauty but first and foremost I have some engine questions. The previous owner overheated the engine. When bought it the thermostat was out. (He told me he put a new one in it) yea right! The car kept running hot, bubbles in the overflow tank and milkshake on the oil dipstick. So I pulled the head off. There were cracks near the coolant passages. I do not want to put this head back on the car. Plus I removed the oil pan and there is sludge in the pan... lots. My question is what size engine and from what years can I bolt to this trans that's in the car? Im assuming the 3.0 from the e12 era or how about a 2.5 or anything out of a e30? Thank you in advance. I will be using craigslist and local junk yards so I would like to keep my options open.

onovakind67 · Post by **onovakind67** » Mon Sep 15, 2014 6:50 pm

Where are you located?

metsfan3321 · Post by **metsfan3321** » Mon Sep 15, 2014 7:45 pm

connecticut

Merlin · Post by **Merlin** » Tue Sep 16, 2014 6:08 pm

Well as far as a bolt up goes basically any M30 will work (later M30Bs require a custom engine mount. think 533, 535, 635,735 etc. I would not recommend a 3.0L because they have bad oil pumps in them and a 3.5L is WAY better. If it were me I would upgrade the engine and the wiring (engine control computer). its an easy job and you get a more reliable system.

I should say there is no repairing the cracked cyl head. you would need to get a new rebuilt one. remember that on these cars the rockers and shafts are not reusable and will fail at some point if you try. Dropping in a good engine is the cheapest and fastest. I recently picked up a 3.5L with wiring harness for my euro 635 for 500 bucks.

Good luck
Sam

metsfan3321 · Post by **metsfan3321** » Tue Sep 16, 2014 6:23 pm

thanks sam. Yea I was thinking of going the way of a complete engine. not easy to find one though. I searched around and haven't found any. I just figured a head would be easiest but you make a good point

metsfan3321 · Post by **metsfan3321** » Tue Sep 16, 2014 7:16 pm

I found a M30 cylinder removed from a 83 633CSi on ebay..... the cam sprocket has a diffent piece on the front.... would this head work on my block?

Merlin · Post by **Merlin** » Tue Sep 16, 2014 7:44 pm

the cyl. head wouldn't work. the distributer is in the wrong place, the size of the bore is incorrect and you would loose compression if it would even clear to begin with. the expense to rebuild the head is more then a good engine, harness and brain.

Sam

Mike W. · Post by **Mike W.** » Tue Sep 16, 2014 10:01 pm

Merlin wrote:the cyl. head wouldn't work. the distributer is in the wrong place, the size of the bore is incorrect and you would loose compression if it would even clear to begin with. the expense to rebuild the head is more then a good engine, harness and brain.

Sam

No, a head off an '83 would work and compression would be the same. Merlin would need the adapter nut for the front of the cam and to use his existing upper timing cover, but it would definitely work.

That said, I would look for a later 3.5 engine, the M30B34 as came in 85-88 E28s is just stupid long lasting, they last almost forever. With one of them you would need to either run E12 FI or change the bellhousing to be able to install the flywheel sensors. M30B35s as came in the last 5 or 6 years are even more of an improvement, more power, better MPG, cleaner, easier to convert the injection as long as you get everything, and while long lasting not quite as bulletproof. The B35s would need a motor mount adapter though. The 2.5's out of E30s will not work, they are a completely different engine family.

But a head alone is far less work and less money than the other options, and stock an E12 is more than respectable, if no longer approaching the current standards of fast. They were in their day, but...

metsfan3321 · Post by **metsfan3321** » Thu Sep 18, 2014 6:05 pm

the Chilton says the head for a 1979 528i is a m20/m86

Mike W. · Post by **Mike W.** » Thu Sep 18, 2014 11:43 pm

metsfan3321 wrote:the Chilton says the head for a 1979 528i is a m20/m86

Then Chiltons is wrong. An E12 528i is a M30 engine and takes an M30 head. It would have a 86MM bore, but it's the big 6, not the small M20, "baby" 6.

metsfan3321 · Post by **metsfan3321** » Tue Sep 23, 2014 5:48 pm

thank you mike. do you think a head off of a 1986 735i e23 would fit my block? or a e28 528i? I saw both on ebay and was wondering... I know the 735i has a chain like mine but the 528i has a belt...

peter claassen · Post by **peter claassen** » Tue Sep 23, 2014 8:51 pm

Where a you located ?Â I am in Redwood City in CA

I have a 83 3.5 head with smooth cam lobes

Probably needs a valve job

On Tue, Sep 23, 2014 at 3:48 PM, metsfan3321 <dane451@gmail.com (dane451@gmail.com)> wrote:

thank you mike. do you think a head off of a 1986 735i e23 would fit my block? or a e28 528i? I saw both on ebay and was wondering... I know the 735i has a chain like mine but the 528i has a belt...

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Mike W. · Post by **Mike W.** » Tue Sep 23, 2014 9:51 pm

metsfan3321 wrote:thank you mike. do you think a head off of a 1986 735i e23 would fit my block? or a e28 528i? I saw both on ebay and was wondering... I know the 735i has a chain like mine but the 528i has a belt...

The 86 E23 one would work with the adapter nut to run the distributor, but one off a 528e will not work, it is an M20 engine/head.

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