Piper COMANCHE PA-24-180 Service Manual page 69

PIPER COMANCHE SERVICE MANUAL
2-80. Oil Filter. (Full Flow.)
a. The oil filter element should be replaced after each 50 hours of engine operation, in airplanes so
equipped. This 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 particle 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.
2-81. Recommendations for Changing Oil. (Refer to latest revision of Lycoming Service Bulletin No. 480
and Lycoming Service Instruction No. 1014.)
a. Oil Change Intervals.
(1) For engines equipped with full-flow oil filters, change the oil and filter each 50 hours of engine
operation or every four months, whichever comes first.
(2) For engines relying upon pressure screen filtration alone, change the oil and clean the pressure
and suction screens each 25 hours of engine operation or every four months, whichever comes first.
b. Ashless Dispersant (Detergent) Oil.
(1) With the exception of turbocharged engines, new or newly overhauled engines should be broken
in on straight mineral oil for the first 50 hours of operation, or until oil consumption has stabilized. Lycoming
oil additive P/N LW-16702 may be used. Mineral oil must also be used following the replacement of one or
more cylinders until the oil consumption has stabilized. Attempting to break-in normally aspirated engines
with detergent oil may result in high oil consumption as the additives in some of these oils can retard the
break-in of the piston rings and cylinder walls.
(2) All new or newly overhauled turbocharged engines must be broken in and operated only with
ashless dispersant (detergent) oil.
(3) In engines that have been operating on straight mineral oil for several hundred hours, a change to
ashless dispserant oil should be made with a degree of caution, since the cleaning action of some additive oils
will tend to loosen sludge deposits and cause plugged oil passages. When an engine has been operating on
straight mineral oil and is known to be in excessively dirty condition, the switch to ashless dispserant oil
should be deferred until after the engine is overhauled.
(4) When changing from straight mineral oil to ashless dispserant oil, the following precautionary
steps should be taken:
(a) Do not add ashless dispserant oil to straight mineral oil. Drain the straight mineral oil from
the engine and fill with ashless dispserant oil.
(b) Do not operate the engine with ashless dispserant oil longer than five hours before the first
oil change.
(c) Check all oil screens for evidence of sludge or plugging. Change oil every ten hours if sludge
conditions are evident. Resume normal oil drain periods after sludge conditions improve.
Revised: 8/15/98
HANDLING AND SERVICING
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