> We need a marine engineer who specializes in this on the list!

Right so a professor of some kind of engineering will probably
do...

Go to the archives (it's not really that painful) and do a
search for crevice corrosion with author Tim Smith (did I spell
crevice correctly?). He did a nice write up on a very good
explanation of why the _ONLY_ portion of the head that pits
is that which is under the rubber gasket (if this was solely
electrolysis, the pitting would be worst at the point where
the coolant flows from thru the head - where it can pick up
ions, not under the protected and insulate surface of the rubber
gasket). There might be an electrolic portion of head corrosion
but it is not the main reason the heads pit under the rubber gasket.

I write this once every 6 months - once everytime this thread
comes up.... Maybe I can make procmail figure out when this
thread is starting again and automaticly send this out again
(and maybe a couple more people will actually go read Tim's
discussion of the elements at work here).

dave