wrote in message
oups.com...
A buddy has an aluminum head on a Rotax experimental plane engine and
he overheated the engine (lost coolant) and got the heads real hot.
Apparently the aluminum is pretty soft now (and the valve guides at
risk for coming out). Can the head be heat treated to temper?

Joe


Yes, but only after being returned fully to a solution annealed condition.
It must be heated quite hot, then cooled quickly. It can then be
artificially aged (heat treated). I don't have the specifics, but that's
how one goes about it. The solution annealed condition is very close to the
melting temperature of the aluminum, so the head may not be of much use when
you're finished with the procedure. I would expect some warping and other
distortion. Hard to say-----

Harold