PA-23-250 Aztec
Maintenance Inspection Authority; Maintenance Powerplant; Maintenance Airframe
Maintenance Inspector 20; Maintenance Technician 45
Other / Unknown
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Incorrect / Not Installed / Unavailable Part; Manuals; Human Factors
After overhauling both engines a ground run up followed. The right engine went into feather due to loss of oil pressure. The left engine started up and ran and exhibited no loss of oil pressure; however; the same incorrect bearings had been installed in that engine as well. Through an over site I mistakenly installed the wrong bearings in both engines. The owners had purchased all engine parts for the repair and had given me all the parts for the overhaul. I immediately informed the owners that I would need to open the cases of both engines and rework the problem. I knew at the time of feather that the bearings were incorrect and they would have to be replaced and I was willing to correct the mistake at my expense. The owners were long time customers with 2 aircraft that I had been maintaining for them for the last 13 years and they had no previous issues with my repairs. They decided that they would not permit me to repair the engines. He took the engines to a certified repair station. This was the same repair station that had certified all the components and provided accompanying documentation to be used in the overhaul of these engines.
A&P mechanic reported that during an engine overhaul; the incorrect bearings were installed in the engines of a PA-23-250 aircraft.