Teacher122@aol.com wrote:
>
>> In a message dated 97-10-03 14:21:34 EDT, saschris@flash.net writes:
>> Seems like I recall some problems with
>> aluminum heads on cast iron blocks, but I may be mistaken there. As i
>> prepare to have my head rebuilt this off season, inquiring minds want to
>> know.
>
> Since aluminum and cast iron expand at different rates, sealing them becomes
> even more of a problem. I've seen enough leaking head gasket threads
> already to know that I'm not interested.
It ain't that big a deal. With good, new head studs and proper torque
(and occasional maintenance), the head gasket will live just as long.
So, how often do yoose guys retorque your heads as part of the usual
maintenance? The racers do it daily.
The iffy part is the electrolitic action of the two dissimilar metals --
you gotta keep fresh antifreeze in there -- stright water can have
corrosion problems.
And its a full point of compression, eg 9.0 to 10.0 to 1.
As for the heat issue, aluminum, with less mass, will not hold heat as
well. The superheated combustion chamber are quenched better as the
surrounding material has less mass and the coolant can wick away the
heat. Cast iron, in comparison, tends to get hot and stay hot.
The problemsome part for the ham fisted is not stripping out the spark
plug holes!
--
Bob Allen, Kansas City, '69CGT, '75TR6, '61Elva(?)
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