20 replies to this topic

[leroy26]

anyone?

[dklawson]

When it comes to re-torquing head bolts there are some different schools of thought. While I don't mind sharing what I do, I am not interested in getting flamed by people who do this differently.

The torque value has to do (a lot) with the condition of the fastener threads and the lube applied to them. For best results the threads need to be lubed so the nuts will run freely on them. A quick visit to the ARP web site will explain this in more and better detail. Regardless, 42 lb-ft vs 45 is a relatively small difference considering that very few of us have calibrated torque wrenches. Go with either value but more importantly keep in mind that smaller studs (rocker pedestals) use lower torque.

My method on re-torque is to let the engine go through several heat cycles then drain the cooling system at least enough to get the coolant below the head. I then get out the manual to look at the tightening sequence. I start with the "first" nut and loosen it 1/4 turn. Then I torque it in one slow, steady, smooth application of torque to the desired setting. When you do this you will probably observe the nut turns more than the 1/4 turn you loosened it. I go through all the other nuts in order till the process is complete, then I re-adjust the valves and re-fill the cooling system.

Some people do not loosen the nuts but just reapply torque from where the nuts are sitting. Generally this does not result in the nuts moving much if at all. The fasteners are more-or-less stuck together at that point. A tiny bit of loosening re-distributes the lube and allows you to move forward to re-establish the desired clamping force.

More info than you wanted, but that is what I do.

[leroy26]

thats exactly what i wanted!
thankyou

[tiger99]

The only difference to what I have done in the past is that I have never bothered to drain the water, and it has never leaked when I loosened any of the nuts, but Doug's method is safer in that regard, so probably a good idea.

[Cooperman]

And that's exactly what I do as well without draining the coolant.

[bmcecosse]

Retorque after the first heat cycle - and I don't drain water OR loosen the nuts - they always come round ~ half a turn. And then re-set the valve gaps of course!