Headbolt Re-Torque

[KenC]

So I just put the head back on my car on Sunday.  We torqued them to the Bentley specs initially.  What is the procedure for retorquing them?  I would assume another 90 degree turn on all of them.
After how many miles should I retorque them?

[kowalski]

the tightening from top right-top left then bottom left to bottom right
7-5-1-3-9 (top)
10-4-2-6-8   (Bottom)

"if the camshafts were removed/installed while the cyulinder head was off, a minimum waiting time is required after installing the camshafts. When the camshafts are removed, the hydraulic lifters can expand/ This expansion can caused increased valve lift, resulting in open valves and piston contact."

wait times at or above 68 F 10 min, 50-68 F 30 min, 32-50 F 75 min
in C its 20, 10-20, 0-10.

first stage of torques
30 Nm or 22 ft-lb's
stage 2 +90 degrees
stage 3 + 90 degrees

to my knowledge this all takes place at the same time, the reason its done in stages is because it eliminates the chance of a warped head, pinched headgasket, etc... as well as it more accurately displaces that actual torque.

[KenC]

Yeah, we did exactly that from the Bentley... through 'stage 3.'  But don't you have to re-torque the headbolts after a certain number of miles and/or hot/cold cycles?

[kowalski]

i do not believe so, thats what the last two 90 degree turns are for, to take care of the expansion shrinkage cycles. I did it through to step 3 about 4 years ago and i have no retorqued them and i'm not seeing any problems with an engine that lives in the redline.