John, from what I've learned about one-piece dead-soft flat copper head
gaskets, they can be used without o-ringing the block but they are prone
to seep at the combustion chamber that way so it is preferable to use
them with wire o-rings. Just as a flat gasket the unit pressure on them
may not be enough to hold the high-pressure combustion chamber gases.
The o-ring technique of choice is a .041" soft iron or copper wire laid
in a groove around the cylinder bore of the block, .030" deep and .040"
wide. This way the wire will be tight in the groove to ease assembly,
and the wire will stand proud of the groove .010" which will create a
high-pressure sealing ring against the cylinder head. The wire ends are
de-burred and just clear each other in the groove.
Some people like old-fashioned aluminum spray-bomb paint for a sealant
with the gasket, others like the rubber-cement-based sealers like
Gaska-Cinch. Either way the copper gaskets with sealant usually seal
the water holes in the block/head interface okay. Bill H.
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