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Head Tightening

Postby David Beatty » 06 Mar 2017 22:33

I recently acquired a V8 roadster conversion and the previous owner suggested that as he had rebuilt the engine the head bolts should be checked for torque.
Having looked at the bolts, some of the outer ones are covered by the exhaust manifold gaskets. I note that these outer bolts are torqued to 44 ft-lbs as opposed to 66 ft-lbs for the other bolts.
Two questions. Is it necessary/desirable to re-torque the head bolts? If so, how do you get at the outer ones without taking the exhaust manifold off the head?
David Beatty
Posts: 6
Joined: 21 Dec 2016 16:14

Re: Head Tightening

Postby Mike Howlett » 07 Mar 2017 09:35

When I rebuilt my V8 engine 28,000 miles ago, I didn't retighten the bolts and nothing untoward has happened. In fact in over 40 years of messing about with cars I have never retorqued a cylinder head and have never had any bother as a result.

Regarding the four lower bolts, later engines omit these bolts and according to Roger Williams in his book "How to give your MGB V8 Power", current thinking is that these "four bolts do little more than distort the head slightly and reduce the pressure on the head gasket at the top of the head/block interface, where the majority of head gasket leaks occur." His advice is this - "my advice would be to lightly slip the bottom row of four bolts into the head just to keep the dirt out. Do not torque them beyond finger tight."

That's what I did.
Mike Howlett
Posts: 130
Joined: 15 Dec 2012 09:27

Re: Head Tightening

Postby David Beatty » 07 Mar 2017 13:49

Thanks Mike. That's very helpful. One less job to tackle.
David Beatty
Posts: 6
Joined: 21 Dec 2016 16:14

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