Album: Post Run Parts
These pictures were taken immediately after running for 2 hours making 145HP (25"Hg @ 2500 rpm) at 70 degF Lean of Peak EGT!
There is absolutely no evidence of any thermal stress on any top end components!
Exhaust valve face and seat are running so cool that it is hard to believe they have been running in 1500 degF exhaust gases! The white powdery coating on the exhaust valve backface and stem are lead deposits from fuel (100LL). Note that the exhaust valve stem actually has nice clean wet oil visible just below the valve guide!
Piston face clearly shows combustion swirl pattern. No sign of any thermal stress on piston face or top ring. Top ring is wet with clean oil.
Last change: 07/03/09
Contains: 4 items.