Rebuilding the head - tips for remove/replace?

My first advice must be to get a later head to renovate.

Original heads on our E9's was kind of an Achilles heel to the otherwise bullet proof M30 engine.

Later heads got more material between the channels and that made the M30 engine immortal.

My exchanged header is stamped 1983.
Before I spent lot of money to get the original header back to business, but with no luck. Cracks between the channels was common on these early heads I was told (afterwards)
 
guide, tensioner and piston.

If you are replacing your tensioner and don't know what you are doing- TAKE A PIC before disconnecting... almost all tensioners are defective now. Make sure it goes back together the right way and be prepared to bend to fit.
 
Update

Here's the low compression culprit, a cracked exhaust valve:
IMG-20120922-00014.jpg



The rest of the engine looks good, no issues during disassembly. The original head is in good shape and I am going to have it gone through, I like having the original one in there and looking at that 72 casting mark. If it blows up someday, my shop has a new 80's head lying around to drop in. I have a beefed up cooling system so hopefully not for a while.

Thanks for all the tips, the removal was quick and painless, I hope the reassembly is likewise. Now to clean and detail.
IMG-20120922-00017.jpg
 
That's good news Steve.

I see you are running the original style red fan. Is that coupled also to the original style friction clutch?
 
Yes I am relieved at the diagnosis. I do have the original style friction clutch but I have it bolted to the always on position. That with the triple core radiator and low temp thermostat, my temp does not go above 4 o'clock in the summer with a/c on.

Luis A. said:
That's good news Steve.

I see you are running the original style red fan. Is that coupled also to the original style friction clutch?
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Good to see it is not too serious Steve. Would anyone know if there is a borescope that could have seen that view through the spark plug hole? Any idea what caused the valve to crack?
 
I have no idea how long it's been cracked, certainly before I swapped the carbs - the triple webers brought this to light because I couldn't get the one adjusted correctly so someone on the sidedraft group suggested I do a compresson check. The car ran well even on 5 1/2 cylinders, which says a lot about these engines. The crack looks like it's been there a while. Can't wait to see what 6 cylinders AND the webers feels like!

Nicad said:
Good to see it is not too serious Steve. Would anyone know if there is a borescope that could have seen that view through the spark plug hole? Any idea what caused the valve to crack?
Click to expand...
 
great news Steve ... i know you are relieved that it is not too major. hope you have it back on the road running fast soon.

scott
 
ho steve
i went through a similar one, but in my case the valve was cracked and a bit of its material went away through the exhaust
the bit was about 5square mm, so the power suddely drop down, and yeah, i noticed it !
wish you a prompt recovery and back on the road again very soon !
regards
 
I didn't feel there was closure or consensus on that thread on whether it is necessary to re-torque the head bolts after 600 miles. The newer bulletins presented by SFDon and others didn't indicate that to be necessary. Nor do the Reinz head gasket instructions indicate that step. Is it necessary or not...?
 
To the best of my knowledge no BMW tech has been taught to re-torque hex head bolts in 30 years. Terrible consequence if you loosen too much as oil will drain down the threads and crack the block when re-torqued.

You can final torque to 100 Nm or you can final torque to X degrees- your choice. There is no final torque of 74 Nm as has been mentioned here-74 POUNDS would be correct.

For myself, I have been testing angle torques with a high end digital torque wrench and I think angle torquing is nuts and results in outrageous final torque numbers.
 
Luis A. said:
I didn't feel there was closure or consensus on that thread on whether it is necessary to re-torque the head bolts after 600 miles. The newer bulletins presented by SFDon and others didn't indicate that to be necessary. Nor do the Reinz head gasket instructions indicate that step. Is it necessary or not...?
Click to expand...

well
i did what is seen in the video
and there are more than 3000km from there now, and it works fine

i reach some kind of agreement on the fact that if you use final step angle torquing, there is no need to retorque

BTW, i had no instructions in my reinz gasket
i followed the instructions on the blue manuals
 
I followed the Elring instructions and there was no mention of a retorque. Car seems fine after 1500 miles.
 
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