"WARREN1157" wrote in message
...
The piston rings rotate whilethe engine is running. The grooves on all of
the
rings could have aligned up with each other for a little while and then
rotated
back into un - aligned positions. If thei happens reguarly the cylinder
could
be out of round.

This condition would make CHT go up and EGT go down

What causes the piston rings to rotate? Since the piston movement is
perpendicular to the cylinder wall, there must be some other mechanism other
than just piston movement causing them to rotate.

Also, why would the grooves on the rings have to be lined up to allow
leakage through the groove?

--
Jim Carter