Piper PA-24 Comanche, Service Manual

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PIPER COMANCHE SERVICE MANUAL
04/01/09 II - HANDLING AND SERVICING
1C39
2-79.
Oil Screen (Pressure).
The pressure screen located in a housing on the accessory case of the engine between the magnetos,
should be cleaned at each oil change to remove any accumulation of sludge and to examine for metal
filings or chips. If metal particles are found in the screen, the engine should be examined for internal
damage. The pressure screen is removed by disconnecting the temperature indicator wire and removing
the four hex head bolts that secure the screen housing to the accessory case. Clean and inspect the
screen. Reinstall by first ascertaining that the screen fits flush with the base of the housing. (Refer to
Figure 2-19.) Install the screen and housing to the accessory case using a new gasket. Torque attaching
bolts within 50 to 70 inch-pounds.
2-80.
Oil Filter. (Full Flow.)
a. The oil filter element should be replaced after each 50 hours of engine operation or each four
months, whichever comes first, in airplanes so equipped. This is accomplished by removing the
lockwire from the bolt head at the end of the filter housing, loosening the bolt, and removing the
filter assembly from the adapter.
b. Before discarding the filter element, remove the outer perforated paper cover, and using a sharp
knife, cut through the folds of the element at both ends, close to the metal caps. Then, carefully
unfold the pleated element and examine the material trapped in the filter for evidence of internal
engine damage such as chips or particles from bearings. In new or newly overhauled engines, some
small particles of metallic shavings might be found. These are generally of no consequence and
should not be confused with particles produced by impacting, abrasion or pressure. Evidence of
internal engine damage found in the oil filter justifies further examination to determine the cause.
c. After the element has been replaced, tighten the attaching bolt within 20 to 25 foot-pounds of
torque. Lockwire the bolt through the loops on the side of the housing to the drilled head of the
thermostatic valve. Be sure the lockwire is replaced at both the attaching bolt head and the
thermostatic oil cooler bypass valve.
Figure 2-18. Oil Suction Screen Figure 2-19. Oil Pressure Screen