What was found
(CAN) ROUGH ENGINE RUNNING LED TO INSPECTION WHICH REVEALED #2 CYLINDER EXHAUST VALVE LIFTER WAS BROKEN. ENGINE WAS REMOVED AND SENT TO R&O WHERE FAILURE WAS ATTRIBUTED TO MISASSEMBLY OF VALVE ROCKER ARMS, INTAKE FOR EXHAUST AND VICE VERSA, THIS CONDITION ALSO AFFECTED #3 CYLINDER. THE ENGINE WAS REPAIRED AND THE AIRCRAFT WAS RETURNED TO SERVICE.