Avidflyer2
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While pulling an Annual Inspection on a new purchase (Seneca II) with a Continental TSIO-360-E (not -EB) engine, I found a piece of metal in the oil pump inlet suction screen. The thickness and radius suggested this was a piece of main bearing shell. Later I confirmed it came from the #3 Main Bearing by first removing a couple of cylinders until careful examination showed the main bearing shift and missing piece of metal. The engine ran fine prior to the Annual Inspection and we had just flown it 12 hours cross country to bring her home. Previous to this the airplane had only flown 7 hours in the previous ten years! Oil pressure had been fine with no other problems noted.
My question is: "What caused this bearing failure?" The size of the metal chunk makes it unlikely that it could have migrated out from between the journal web in the crankcase and the crankshaft. Some have suggested this was an installation error and it took this long for the metal to migrate to the screen. I have seen "bearing shift" before, but not bearing shift with bearing fatique causing a loss of bearing shell or insert.
Yes, cylinders have been replaced in the past, so it is possible that crankcase thru bolts and or cylinder thru bolts were not properly torqued. They were torqued prior to me removing them, I checked the torque on all thru bolts prior to disassembling the engine.
My question is: "What caused this bearing failure?" The size of the metal chunk makes it unlikely that it could have migrated out from between the journal web in the crankcase and the crankshaft. Some have suggested this was an installation error and it took this long for the metal to migrate to the screen. I have seen "bearing shift" before, but not bearing shift with bearing fatique causing a loss of bearing shell or insert.
Yes, cylinders have been replaced in the past, so it is possible that crankcase thru bolts and or cylinder thru bolts were not properly torqued. They were torqued prior to me removing them, I checked the torque on all thru bolts prior to disassembling the engine.
