need opinion on retorquing head bolt

[1 FMF]

in regards to previous post about thread sealant, the service manual says to retorque cylinder head bolts (to 90 lb-ft) after first 20 hours of operation. I have 40 hours on the motor, and will be checking the valve adjustment tomorrow along with some other maintenance.
Does the following sound safe to do: either loosen, or remove and apply thread sealant, one head bolt at a time, then retorque to 90 lb-ft. There's 10 head bolts holding the head. The only concern I can see is the intake/exhast manifold that's mounted to the head, but since I'm doing one bolt at a time, it should be ok, right?
I figure this would be good to do now since I'll be loosening all the rocker arm nuts and will have access to the head bolts.

Motor is a 2002 inline-4 3.0L Mercruiser (GM block).

 

[D Stewart]

Don't do it. While a retorque simply resets the bolts (takes up the streatch). A total unload (loosening/removal) requires new bolts.

 

[rpn453]

quote:

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Originally posted by D Stewart:
Don't do it. While a retorque simply resets the bolts (takes up the streatch). A total unload (loosening/removal) requires new bolts.

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I thought retorquing was for restoring the clamping force on gaskets. I wouldn't think you should ever be torquing a bolt enough to exceed the yield stress of the material. I could be wrong though.

 

[Eddie]

Don't remove. Just torque to 90 ft/lbs. You are slightly strecghing the bolt but, not to the yeild point. Big difference