What was found
(CAN) AIRCRAFT IS OPERATED BY BUSY FLIGHT TRAINING UNIT NO COMPLAINTS OF ENGINE MALFUNCTIONS HAD BEEN REPORTED. ENGINE WAS RUN UP, FOUND NORMAL, PRIOR TO INSPECTION. OIL SUCTION SCREEN WAS INSPECTED AND FOUND CLEAN. OIL PRESSURE FILTER WAS CUT OPEN AND A SMALL AMOUNT OF STEEL FILINGS WERE FOUND ON FURTHER INVESTIGATION BY REMOVING NR 1 AND 3 CYLINDERS. THE AFT INTAKE LOBE ON THE CAMSHAFT WAS FOUND TO BE ALMOST NON-EXISTENT. THE ENGINE WAS SENT TO AN OVERHAUL SHOP FOR REPAIRS.