What was found
DURING A PHASE 2 INSPECTION, CYLINDER NR 5 WAS FOUND TO HAVE LOW COMPRESSION (5/80) WITH A STRONG LEAK PASSED THE EXHAUST VALVE. SUBSEQUENT INSPECTION FOLLOWING THE INSTRUCTIONS FOUND IN SB 388C REVEALED THE CYLINDER DID NOT MEET THE MEASUREMENT CRITERIA FOR THE EXHAUST VALVE GUIDE. THE MEASUREMENT TAKEN BEFORE REAMING (IAW SB388C) WAS .007 INCH. THE EXHAUST VALVE WAS REMOVED FROM THE CYLINDER (WITH THE CYLINDER INSTALLED) AND EXHAUST VALVE GUIDE WAS REAMED. A COMPRESSION CHECK WAS TAKEN AGAIN ON CYLINDER NR 5 AND COMPRESSION AFTER REAMING WAS 77/80. MEASUREMENT AFTER REAMING WAS .0175 INCH. THE PERMISSIBLE RANGE IS .015 TO .030 INCH. CYLINDER NR 3 ALSO FAILED THE MEASUREMENT CRITERIA OF SB 388C. THIS EXHAUS