e9 cylinder head crack

jeme9

jeme9

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Hi, has anyone seen a crack like this (cyl 5).
it is in the centre of the photo (below spark plug, to exhaust valve):
fullsizeoutput_1252.jpeg

There is also a crack on the other side of the exhaust valve:
Z5HlydFFQFyJkDFi%EbEPw.jpg


Note: there is also a traditional crack on cyl 3 from water jacket slot
 
I am rather new to the forum ! But mine was almost like yours. What is the year manufacturer code on the side of the head?
Is the head the original head that came with the car?
 
Thanks Tony, good to see I am not the only one!
It is stamped as 1972 build (72) which fits in line as the original head.
Originally it was carbs car, but I added the injection from a 3.0si (L jet) about 10 years ago.
 
You are more than welcome! You should try to buy a m30 head with date stamped preferably 82 or later. In the us they are around 200 to 250 for 82 and about 400 for 85 . M30 engine was probably the most legendary L6 Engine so you should be able to find them . I think M30 lasted through 1990 or 1991 . So all thier head should work. But for some reasons I see members that know more than I stop at 85. When yo get a new head You will immediately notice the water jackets. On your 72 water jacket is so big making the cylinder wall so thin. On top of that the alluminum alloy BMW used back then warped easily causing the head gasket to Breach .
Make sure you look for a cylinder head that has a little tip(tongue) sticking out of the front. If it has been machined you will be able to tell because that tongue (I call it, some call it ear , or lip) is gone. Do not waste your time or money buying a machined head. Even if it works now , you will have other compression etc. issues ..
Contact SFdon or HBchris , or Markos , they are all super super nice guys . And can give you more precise advice!
Best wishes !
 
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Thanks Tony, I will look out for the tongue / ear, lip thanks
I have not done many miles in the car in the last 20 years (?) it has already been a weekend car, with the occasional track days (in Australia),
thanks
 
Timely conversation for me as I was recently contacted by a local shop that is replacing the head, due to cracks, on a '73 E9. The car only has 85K miles and is already on its second head, date code '75. The shop owner is a good friend and knew that I had some contacts locally. Long story short, it looks like BMW still offers the correct head for a M30B30 carb car. If that is true then that would be the best route. That's what I recommended and I'm waiting to see if the heads are in fact available.

As for as the compatibility of later heads its important to note that any head from a car with motronic engine management will have an upper timing chain cover made to fit the motronic distributor cap. I think, although I don't have a personal experience, that you can switch to your old cover designed to hold a standard points distributor. There is still the issue of no place to mount a mechanical fuel pump and also the fact that the valve cover bolt pattern is slightly different. None of those are a deal breaker I guess.
 
RIght, I think w/stock compression, people gravitate towards the B34 head. If you're putting in hi-comp pistons, than a B35 I hear is nice w/the larger combustion chambers for hot rodding.
 
Yes, that head crack at the exhaust valve to the water jacket is very common. My original had 2 fractures at 2 & 4.

Try to source a head from a 1985 M30 or later with the drilled water jackets. I'm running a 1986 head from an E28.
 
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