For engine DIY'ers

[Gene]

and you have installed cylinder heads...
Bolting it back together, you have to torque the headbolts, making sure to do it in a cross pattern according to the manual.

My Dad the mechanical engineer had some advice, I wonder what you think.
1) Tighten the head bolts in stages to the proper torque.
2) Once you have them tightened, loosen all bolts again, (in stages)
3) repeat number one.

According to him, this helps to "lessen" or elimiminate any residual stress.

Anyone else do this?

[Pete in PA]

I agree with #1, but not the rest.

You follow the manual exclusively.

[mollusc]

If you follow a staged tightening process, that should prevent any torsion stresses developing in the head.

Also -- although not applicable to Nighthawks -- loosening a TTY head bolt will ruin it, so there's no way that I would do this on a vehicle that uses that type of head bolt.

[Bob H]

2) Once you have them tightened, loosen all bolts again, (in stages)

I never did that on the heads I worked on - and never heard of it before.

Looking at theory to do that or not, I would imagine the more important concept is getting that head gasket compressed to proper spec and leave it alone. Walk away slowly, don't spook it.

[mollusc]

^^^^
Another excellent reason not to do this.  Head gaskets compress, and don't spring back.