X-Mozilla-Keys:                                                                                 
Russell Kent wrote:

In a discussion regarding ceramic coatings on engine components,
particularly piston heads, Archie wrote:

We have ceramic coated the piston tops on Nitro, Alcohol,
and Gasoline burners. It seems to be most effective w/ gas.
The heat barrier is worthwhile in Nascar, and Drag cars.
Since I have no experience coating cast iron pistons,
the effect of coating a rotor is beyond my experience.

I'm going to speculate that the ceramic coating on the head serves to
prevent piston head burn-through by preventing the formation of hot spots
on the head.  The thin ceramic layer slows the heat propagation (through
it) to the point where the piston's much higher thermal conductivity
allows it to uniformly distribute the heat throughout the piston.  There
may still be hot spots on the cermaic coating (on the combustion side),
but the ceramic can take the heat.

As a seconday effect, the ceramic's surface will be hotter than the naked
piston head (slower heat propagation in ceramic versus metal piston),
which probably helps prevent carbon deposits from forming.

Russell Kent

 
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