What was found
ENGINE RAN INTERMITTENTLY ROUGH . NR 1 CYLINDER SHOWED VERY LOW EGT AND CHT. PERFORMED COMPRESSION TEST ON NR 1 CYLINDER. COMPRESSION WAS LOW AND AIR WAS ESCAPING PAST EXHAUST VALVE INTO EXHAUST STACK. R & R CYLINDER WITH REPAIRED AND INSPECTED UNIT. REPORT SHOWED REMOVED CYLINDER TO HAVE WAVY WALLS WHICH COULD NOT BE RETURNED TO STANDARD LIMITS AND WOULD REQUIRE HONING TO P.015 OVERSIZE. THE EXHAUST VALVE GUIDE WAS OUT OF LIMITS. THE EXHAUST VALVE WAS BURNED AND UNSERVICEABLE. PISTON CHECKED OK.