What was found
PILOT REPORTED DURING CRUISE OPERATION A SUDDEN ENGINE ROUGHNESS WITH A LOSS OF POWER. EMERGENCY LANDING REQUESTED AND COMPLETED AT KOXR. INSPECTION OF ENGINE FOUND CYLINDER NUMBER 3 WITH HOLE THROUGH INTAKE PORT AND REAR BAFFLE. BORESCOPE INSPECTION REVEALED BROKEN INTAKE VALVE. INTAKE VALVE TOP AT RETAINER KEYS STILL CONTAINED IN SPRING CAP WITH VALVE ROTATOR INTACT. INTAKE VALVE HEAD CONTACTED PISTON AND LODGED IN INTAKE SEAT. COMPLETE BROKEN INTAKE VALVE STEM EXITED THE CYLINDER THROUGH THE INTAKE PORT AND REAR BAFFLE OVERBOARD DURING FLIGHT. NO OTHER ENGINE DAMAGE FOUND. ALL DAMAGE CONTAINED TO CYLINDER NUMBER 3.CONTINENTAL MOTORS (CMI) CONTACTED FOR WARRANTY AND INVESTIGATION OF FAILURE. CYLINDER RETURNED TO CMI FOR EVALUATION AND REPLACEMENT RMA10818. CMI NEW FAA-PMA CYLINDER KITS INSTALLED AT ENGINE OVERHAUL 28 HOURS AGO, CMI 8130-3 NUMBER 4516CA.