What was found
ON A TRAINING FLIGHT, THE ENGINE STARTED RUNNING ROUGH. INSTRUCTOR REQUESTED DIRECT RETURN. WHITE SMOKE CAME FROM ENGINE, A LOUD BANG, FOLLOWED BY VERY ROUGH ENGINE AND PARTIAL POWER LOSS. ENGINE STOPPED, SAFE LANDING, CYLINDER HEAD AND TOP ONE-THIRD OF BARREL SEPARATED FROM LOWER ONE-THIRD OF CYLINDER. PISTON DESTROYED, PUSH ROD BENT, SUBMITTER STATED CAUSE WAS DEFECTIVE CYLINDER BARREL, PREVENT BY USING NEW CONTINENTAL CYLINDERS.