cylinder head and cam ID

sfdon

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The 89 head has no dimples left.
It’s been cut too much
The b35 head will drop your compression by about 1 point.
You can cc it for the exact amount
Look for a 1983 or later head. (1983-1987)
They don’t crack.
Or- a euro m90 or a 10:1 euro engine or a b35 Engine
All are 200+ HP
 

sfdon

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7008D513-6750-4152-9B85-5C6CA926CFC7.jpeg
4 dimples.
 

autokunst

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This is great information!!! Say, regarding the dimples (which are a great visual clue): Do they have a direct relationship with the specified data for the head? The blue book reads that the head should be 129mm +/- .1mm, and that it can be planed down no more than .5mm to true it. Are the dimples .5mm deep? Just curious if they are right on the money, or if once they are gone you are well past the spec. THANK YOU!
 

Gransin

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Yes, that was a great tip! Never knew about that.
Had to go back and check the pictures from my recent head replacement, I told the machine shop specifically that I was worried about the "height" of the head, and asked if they could measure it before they do anything to it, and only proceed if it checks out okay. "Absolutely" was the answer, they knew M30s in and out. A couple of days later they called and said that everything was alright and the head was planed and ready for pickup.

Soo, now I'm checking the photos of the newly planed head, and guess what, no dimples.. :rolleyes:
 

Markos

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Going to look at my dimples tonight. I have my spare head up on the bench for some DCOE linkage and fuel setup.
 

sfdon

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For a guy buying a head you just need to know “No dimples no thanks”
There’s exceptions to everything- Spanish heads don’t have dimples.
You can assume every head will get cut 5 thousandths of an inch.
That means you need to start with 10 thousandths more than minimum to consider buying that head.
 

sfdon

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Installing a thin head will move your cam/crank timing about 2-3 degrees at the cam and make your low end power go away. Slotted cam gear will fix that. They aren’t cheap. You need to punch out the pin to attach. Although the torque on the 4 bolts is only 12 Nm at 6000 rpm it’s a good idea to use thread lock.

Guys- /kizilsakal asked about the 1989 head. Not about all heads.

Don’t run too far with this. 1980’s b34 and b35 heads have dimples.
Bean heads don’t.
 

Stevehose

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Don, what are your thoughts on the thicker head gasket to accommodate the shaved head and therefore supposedly correct the timing and clearance issues?
 

sfdon

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The problem right now is not heads for NA coupes. They are out there. Nobody really wants the originals because of the porting and the cracking issues.
Csi and Csl heads are a disaster. Injected dated heads are really hard to find.
M90 heads can be found in early and late versions and created out of m30 heads.
Tons of b35 heads.
 

teahead

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So, he should find either:

(1) nice, non-cut B34 head, or
(2) low mileage, good running (not overheated) B35 engine

?
 

teahead

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I think he should install a m90 engine.

Ya, but aren't those hard to find? I think I saw one for sale in the NW area (Portland I think) maybe two years ago for at least $1600. I got a whole wrecked 91k mile '89 535i for $400.

Finding a wrecked Euro E24 will also be hard to find. Ditto a E12 M535i.

M90s are...218HP? vs 208 (I think) for a b35?
 
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sfdon

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I bought 6 last year
The one in Redding 2 days ago
A rare motronic m90
I think Bert has the same iteration
2nd gen m90 engine with motronic

Go check the hp and torque numbers for rpm for both engines.

If cost is your only criteria you are buying value meals at Burger King.
;)
 

Markos

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Ya, but aren't those hard to find? I think I saw one for sale in the NW area (Portland I think) maybe two years ago for at least $1600. I got a whole wrecked 91k mile '89 535i for $400.

Finding a wrecked Euro E24 will also be hard to find. Ditto a E12 M535i.

M90s are...218HP? vs 208 (I think) for a b35?

M90’s are out there. It is difficult to find a bare m90. You generally need to buy the whole car and pay $1,000+ to transport it, pay to remove the driveline (or DIY), pay to store (or piss off your spouse), then pay to get rid of it. Depending on where you live and how you handle the carcass, pay to have it titled in your name.

A B35 is the path of least resistance but the m90 is a sweet motor. I only envy them on paper though as I haven’t driven them yet. I like oversquare motors. My first car was a volvo red block.
 

restart

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Sfdon, I have a question pleas..
4596BE08-C301-4FEE-8E2A-5FBD3ED4FC41.jpeg

That middle head in your pic looks like it has some epoxy work at the port.? Or is that just a shadow.
Reason I ask is I have an intake manifold off to replace starter and the gaskets that were on the car are incorrect.
I have in stock five correct ‘humped’ gaskets in the stash but can’t find a sixth.
So, my question is...
I could just fill that spot cutout with epoxy?
like the one in your pic seems to be?

and then use a ‘non-humped’ gasket of which I seem to have millions.


Here I s a pic of the effects of the wrong gasket, it looks like all six cylinders were leaking minutely at he very edge of the previously installed non-humped wrong gasket?

77193E2A-3E2C-45E3-BE33-9B4E29CC4275.jpeg


You can see the ghosting from the intake leak.
7A19A34E-25C8-46BE-806F-A54594632A1A.jpeg 92C42A1C-D76E-4A00-A851-80B72765A165.jpeg
Thanks in advance for any reply!
 
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