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MG MGA - Head re-torque

Hey all, after 3 long years, I am getting close to the initial stat up. My question is this: After the initial warm up, should I let the engine cool before re-torquing the head?
As ever, Thanks, Tom
Thomas McNamara

Hi Tom

Is it not normal to run the engine for a couple of hundred miles before re-torquing the cylinder head and then it's done cold.

Barry
B Bridgens

It doesn't matter. The head and block and studs all have the same expansion coefficient and are at the same temperature by the time the engine has stopped for a minute or 2.
Art Pearse

My engine rebuilder told me to wait until I had about 500 miles on the rebuilt engine before re-torquing.

Also when you re-torque the head bolts, do them one at a time. Slack off 1/4 turn then re torgue to specs. Don't slack off all at once.... and then re-torgue. That will create a problem. Take it from one that has done it the wrong way.
Ray Ammeter

I re-torque hot just after the initial cam run-in (2500 rpm for 20 minutes). There does seem to be a considerable amount of additional turning, like at least 1/4 turn to get back up to the torque spec. That could be about 0.010 inch of additional compression on the head gasket (if the steel studs did not expand more than the iron parts. I attribute this "settling" to additional compression of the head gasket after it gets hot. I have been using the black fiber Felpro/Payen head gaskets for the last 15 years, and only occasionally a gray fiber gasket. I don't know if this applies to the laminated metal gaskets, as I haven't used one recently and likely never will again.

I will also re-torque hot after 500 miles just for an assurance check, but the bolts don't seem to tighten up much more at that time. I take this to mean that it is not needed then, but it makes me feel good about having done it right after the first warm up.

If you install an aluminum head, disregard everything above and follow the manufacturer's instructions. An alloy head is almost always torqued or re-torqued when cold after it has contracted to be slightly thinner).
Barney Gaylord

This thread was discussed between 24/09/2012 and 25/09/2012

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