Head crack

IMAG0445_zps075286fa.jpg


So the bolts that wouldn't torque up are stretched. I don't understand this. I did everything by the book and used the elring retorque directions with new head bolts from w+n.

The bolts are not stretched more than the depth of the bolt hole.

I hate m30s.
 
Defective bolt?

Is it just one bolt that stretched? If so, perhaps it was simply a defective bolt. It is odd that it would stretch but not show signs of twisting or shear off completely.

As to your other problem. I think early 80's head will work on the old block ('80/'81). Find a used one and have it rebuilt and gone through by a machine shop.
 
What matters is the part # of the head, not the casting date, if you are asking if a head off a 1989 model year BMW will work on an early block, no it will not. You can have an earlier part # head with a 1989 casting date as BMW was still supplying them. Not sure what an 1985 head has to do with it as I "think" any 1985 M30 head will work on an early block as the big valve motor did not come out until sometime in 1987.

Al

PS, I have some euro L jet heads if you are interested.
 
Problem with any original '89 head is that matching it to an
early block will result in low compression. All cars with big 6
engines in the USA in 1989 were m30 b 35 models.
Quincy- I'm not sure what you mean by you have an 85 head- ?
A m30b34 head is completely different from a m30 b 35 head.
 
Check this excellent write-up on M30 heads.

http://www.firstfives.org/faq/cylinder_head/cylinder_head_faq.htm

Basically you can mate any E3, E9, E12, E28 and E24 (up to 8/87) M30 head to the original block and pistons in an early M30 (like ours). M90-engines (3430 cc 78-82) are another story but can be made suitable according to above mentioned link.

Fitting a later style head (E24 from 88, E32, E34) will lower the comp rate to a well below 8:1 figure (depending on original spec US/Euro), only suitable for turbo or SC-engines.

Good luck!
 
DerSchwede said:
Check this excellent write-up on M30 heads.

http://www.firstfives.org/faq/cylinder_head/cylinder_head_faq.htm

Basically you can mate any E3, E9, E12, E28 and E24 (up to 8/87) M30 head to the original block and pistons in an early M30 (like ours). M90-engines (3430 cc 78-82) are another story but can be made suitable according to above mentioned link.

Fitting a later style head (E24 from 88, E32, E34) will lower the comp rate to a well below 8:1 figure (depending on original spec US/Euro), only suitable for turbo or SC-engines.

Good luck!
Click to expand...


vielen danke for reposting this very interesting and useful doc
i have been trying to find it for ages...
MFG
 
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