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Torque cylinder head bolts
XBB240 Offline

Posts: 17
Joined: Aug 2017
Location: Sweden
Torque cylinder head bolts
I Mounted my cylinder head on my om606 and I used the following torque
First 15nm then 35nm then 90 degree waited for 10 min and then 90 degree again 
unfortunately I hade to remove the cylinder head again and when I did that after 3 days
And when I did that I could easy losen the bolts and I saw that the bolts has not been stretched as the old ones had, and the old ones was realy hard to get lose 
Have I missed something I am going to install the cylinder head again now in the weekend with new gasket and new bolts 
Shall I put some copper spray a gasket on the new gasket to get extra seal?
05-09-2019, 04:12 PM
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AlanMcR Offline
mind - blown

Posts: 306
Joined: May 2009
Location: USA
RE: Torque cylinder head bolts
Are you sure the bolt holes were clean and dry all the way to the bottom?

Check the bolts that you removed for stretch:
102mm or 115mm when new
104mm or 117mm max length (max length before the last use)
That is measured from the clamping face all the way to the end of the bolt.

I've only seen one failed bolt. It stretched ~2mm due to an overheat situation. The failure occurred right where the threads exited the block and it was obvious that the thread pitch changed.
05-11-2019, 11:01 AM
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Hercules Offline

Posts: 217
Joined: Nov 2010
Location: Fresno,Ca.
RE: Torque cylinder head bolts
Normal for head bolts to be hard to break loose after long period of time.Also includes most bolts.
Light lube on head bolts including under head I believe is suggested.
Head gasket to be installed dry,last I heard,has adhesive on already.
05-11-2019, 11:56 AM
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