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Lycoming Oil Pressure(2)

Time:2018-10-28 21:57Turbochargers information Click:

Engine pressure Lycoming Pu

Lycoming Oil Pressure

This pressure is higher than the oil system pressure of 55 psi to 90 psi. Lycoming Service Bulletin No. 555 was issued as a result of one engine (a TIO-540-AK1A) that was returned to Lycoming due to low oil pressure. The engine oil pressure dropped from 65 psi to 30 psi during flight. At engine disassembly, the following was found:
The P/N STD-1339 Allen type pipe plug was missing from the oil pump body. This explained the reason for the drop in oil pressure. There was light damage to the accessory gears. The Allen type pipe plug was found in the engine oil sump. This explained the reason for the damage to the accessory gears.
34. Continental - Oil pump drive shaft broken. Reference Airworthiness Directive 81-13-10-R1 or latest edition.

35. Bearing Failure - Erratic oil pressure and lots of oil out engine breather caused by bearings failing and spraying lots of oil from journal. Picture below shows bearing that has shifted laterly out of bore and is cracked. Caused by loss of crankcase clamping force due to use of sealant on journal bearing support surfaces. Sealant collapsed (ran away from the stress) creating a lose joint and allowing the bearings to move.

Description of symptoms: We pulled this engine off of a TU206G that was experiencing oil pressure anomalies and a heavy ( uncontrollable ) amount of oil on the belly ( there were two oil separators )- We tested and eliminated all conclusions until we got to the one about oil being atomized into the inside of the case and then blown out- We pulled the engine and then the oil pan.. and pressurized the oil galley ( with shop air ) through the filter to see where the oil was spraying into the engine case.. We found that it was principally from the split bearing-
In the end the problem was attributed to the appropriate sealer being used in an incorrect area.. On the main journal faces- The sealer was applied after the dimensions were checked and allowed the space to be filled, and the torque to be reached, before the clearances were correct- You can clearly see the movement of the bearings in the case-
I have piles of photos.. but these were the more appropriate. The engine had be opened preventativly ( no damage was found ) 250 hours earlier for a separate low pressure condition due to a turbo oil line nut at the wastegate coming loose-


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