Comparison between Unleaded Automobile Gasoline and Aviation Gasoline on Valve Seat Recession in Light Aircraft Engines
NATIONAL INST FOR PETROLEUM AND ENERGY RESEARCH BARTLESVILLE OK
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Testing was conducted to determine the potential for excessive valve seat recession in light aircraft engines using unleaded automobile gasoline autogas fuel. Two IO320 Lycoming engines were operated on a test stand for a 150-hour duration one engine used 100LL aviation gasoline avgas and the other used unleaded premium autogas. New original equipment manufacture valve seats hardness Rockwell HRB 40 were installed at the beginning of the test and recession was measured at 16-hour intervals. The air-fuel mixture was precisely controlled by monitoring exhaust gas composition. Results show valve seat recession using unleaded autogas fuel was not significantly different from 100LL avgas.