General question. This was a debate around the garage last night. When you are re-torquing the heads. Do you first break the bolt of nut loose then torque to spec or do you put the wrench on an see if it moves and torque it that way ?

Well, there's no owners manual in racing so it's up to the individual spending the money in the end. I subscribe to the break it loose then re-torque method. You're familiar with breakaway torque and the need to over come initial resistance. The same would apply to an already tightened fastener. So you break it loose then come up to full torque immediately.

Thought they quit doing that years ago...

I follow canted valves method. Works for me. On disassembly the center of the head gasket is cleaner. Looks like gaskets stay sealed better. This is a sbc with aluimium heads, iron block.

I have been re-torquing my heads after a few races and heat cycles. When I do I just torque them and do not back them off and reasoning there for what it is worth is I want to know if they are tightening up any and they do. That tells me it is a good idea to do it even though most head gasket manufacturers say it is not needed. I feel it helps and gives added safety.

Many years ago Fel-Pro came out with a suggested method for doing it. I can't find it anywhere now but what they said to do was torque all bolt/studs to the number. Let it sit over night so that it crushes to it's designed thickness.

Then do as Canted Valve said. Break each nut/bolt loose in the normal sequence one at a time and torque back to your number before moving to the next and you are good to go. No need for a heat cycle. This is the method that we have always used.

Curtis

I remember reading what Curtis Reed posted.

I have seen this on a BBC with both a steel and AL block with AL heads.

Some are still at the set torque, some are loose and some that hit the original torque value without moving, when loosened up about a 1/4 turn return back to the original spot and some turn more to get the original torque!
So if you retorque and want it to mean anything, for those that don't move, you need to back them off a bit and then retorque, if your curious if it was loose, locate a point on the hex and a reference spot on the head prior to loosening and then back it off a bit and retorque, then you can see if it moved or not.

I'll add this too, new heads may loosen up more than ones that have been run and I have also seen small diameter washers which tend to sink into the heads that also cause issues.

Should be no need to re torque.
And depending on how long you ran it the majority
of the thread lube has washed away, so if you dont remove and clean and re apply your favorite lube the retorque will be meaningless.
Oh ,and torque should be what the block was bored and honed at

quote:

Originally posted by Bad News:
Should be no need to re torque.

You can say that all you want and when you don't make a decent amount of power, your correct but not in all applications does that apply!