What was found
(CAN) THE OIL USAGE OF OUR 3 ACFT HAS BEEN EXCESSIVE AND WITH NO SUGGESTIONS FROM MFG OR AMO. TOOK ACFT TO THE MFG FACILITIES. THEY TORE THE ENGINE APART AND FOUND MULTIPLE PROBLEMS ESPECIALLY PITTING ON THE LIFTERS. INSPECTED THE OTHER ACFT: BOTH ENGINES ON SECOND AIRCRAFT WERE FOUND TO HAVE PITTED LIFTERS. THIRD AIRCRAFT HAD AN ENGINE REPLACED, IT HAS 226.6 HRS SINCE NEW. WHEN BORESCOPED IT WAS FOUND TO HAVE NO PITTING. THE LT ENGINE WAS FOUND TO BE PITTED AS WELL. THE ACFT ARE GROUNDED AND IN THE PROCESS OF ORDERING 5 NEW ENGINES.