<All> Head bolt torque tips

[quk@isham-research.demon.co.uk (Phil Payne)]

In message <A06497019B@agcom.tamu.edu> "Al Powell" writes:

> 2)  AFter torquing all the head bolts, let them sit for an hour or
> so, then back each bolt off about 1/4 turn, and re-torque.  If you
> mark each bolt relative to the head, you will find the bolts turn
> farther the second time it's tightened to the same torque spec.  This
> evidently "overcomes the breakaway torque" required to reach
> the final torque setting the first time.
>
> The floor is open for discussion......

DON'T DO THIS TO AN AUDI.

The head bolts are taken beyond the elastic limit in torquing.  If you
want to see what this means, measure the bolts before and after use.

Audi head bolts are _not_ torqued in the classic sense.  They're
inserted, torqued (usually twice at 40Nm and 60Nm) and then turned
180 degrees - the final stage has no defined torque value.

--
 Phil Payne
 Phone: 0385 302803   Fax: 01536 723021
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