Jim---I see what you mean about blowback thru the carbs, when caused by
an exhaust valve not opening. During what should've been valve overlap,
compression could've been very high. But it would seem to also be true
if an intake valve failed to close. (As in the case of a wayward
pushrod, and such intake valve held open by a galled guide)
It is also true that the exhaust valves typically run hotter, but their
stems are of smaller diameter to allow for this probable expansion.
There is too much not known on how these valves were seating to know how
the heat was being carried away.
My money is on intakes failing to close, rather than exhausts failing to
open. This is just speculation, based on the force of pushrods being
able to jam a valve open, vs. the lesser force of return springs being
able to close a valve on a galled guide.
Time will tell, when we get the report back on what all transpired.
Meanwhile, this is all fun and games except to the soul in which it
happened.
Dick
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