The way I learned it, after the engine heated up and cooled down, the
head gasket would compress a bit but not evenly. So the idea of the
re-torque was to even out the clamping force again. Some nuts/bolts
would move a bit, some not, according to how much the gasket had
compressed.
Well, with the idea being to make sure the fasteners are stretched to
the center of their elasticity range and that the clamping force on the
gasket is correct, it doesn't seem reasonable to back the torque off
first. IMHO, YMMV,
CR
mgamgb wrote:
> Reverse order IS correct but one at a time. Un-Do approx. 1/4 to 1/2 turn
>> (just so exsisting torque is defeated.). Retorque.
>
>
> Retorquing the head studs is going to result in an increase in clamping
> of the head to the block.
> The effect is an extension of the same loading that is applied when the
> head is first attached and the nuts torqued up.
>
> This suggests to me that the normal tightening sequence rather than
> reverse sequence should be followed.
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