What was found
LT ENGINE, AFTER NOTICING MANIFOLD PRESSURE SPLITS, AND A COLD RUNING NR 3 CYLINDER, INSPECTED AND FOUND INNER AND OUTER EXHAUST VALVE SPRINGS BROKEN. REPLACED BOTH SPRINGS. SUBSEQUENT FLIGHT, LT ENGINE OK, BUT NOTICED AN OCCASIONALLY MISS AND COOLER RUNNING NR 6 CYLINDER ON RT ENGINE. INSPECTED AND FOUND THE INNER SPRING BROKEN ON NR 6 EXHAUST VALVE. REPLACED BOTH SPRINGS FOR NR 6 EXHAUST VALVE ON RT ENGINE. NEXT FLIGHT SAME DISCREPENCY, ONLY REPORTEDLY NR 2 CYLINDER RUNNING COOLER. INSPECTED, AND AGAIN FOUND INNER VALVE SPRING FOR NR 2 EXHAUST BROKEN. REMOVED ALL REMAINING VALVE COVERS FOR BOTH ENGINES. FOUND ON LT ENGINE CYLINDER NR 2 EXHAUST INNER SPRING BROKEN AND ON RT ENGINE CYLINDERS NR 1,2, 3 AND 4 EXHAUST INNER SPRIING BROKEN.