Piper COMANCHE PA-24-180 Service Manual page 388

With the engine thoroughly warmed up and running at a maximum of 2200 RPM. observe the reading
on the oil pressure gauge If the pressure is above 90 psi. stop engine. loosen the adjusting locknut: and b
off the adjusting screw one or two full turns. Tighten locknut and retest If pressure is too low turn adjust
screw further into the relief valve plug. thereby increasing the tension on the relief valve spring When the
valve has been satisfactorily adjusted. tighten the locknut and lock wire the crown nut to the drilled ear
projecting from the salve mounting boss
7A-85 Oil Screen. The oil screens are the pressure screen. located in a dome shaped housing. above and
between the magnetos and the suction screen located in ihe lower aft section of the sump These screens
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 oil screens. the engine should be examined for internal damge
a
To remove the pressure screen. remove oil temperature electrical lead or the temperature bulb and
the cap screws securing the housing Note the location of the screws as the round fillister head screw. if
installed. must be returned to upper right corner of the housing If the fillister head screw is not reinstalled
in the same hole from which it was removed. it is possible to crack the mounting flange of the vacuum pump
b
With the housing and screen removed. clean and inspect both items, check the matir
u rtace of
the housing and accessory case for gasket particles
c.
Insert the screw into the housing so that the screw fits flush with the housing base L sing a new
gasket. secure the housing to its mounting pad and torque cap screws to 75 inch pounds
d
The suction screen is remox ed from the sump b! removing the hex head plug at the lower aft part
of the sump Clean and inspect the screen and gasket. replace the gasket if over compressed or damaged
Insert the screen full! into the sump. install gasket and plug. Safety the plug
7A-86 Oil Cooler.
a
When conducting a routine engine inspection. the oil cooler(s). lines and fittings should be checkew
for the following
I
Oil cooler line attachments should be examined to be certain that all are tight and there s
'
indication of crossthreading
(See C for oil line torque.)
2
Oil lines must have adequate clearance and be properlk aligned
3
Oil line supports should be tight. properil positioned and if worn should be replaced
4
Oil cooler should be checked for leakage or distorted.cells
5
Cooling fins should be clean and undamaged.
b
During each engine overhaul. at indications of high oil temperatures or during a 500 hour
inspection. the oil cooler should be removed. cleaned and checked for damaged fins and cells When
replacing the cooler. properlh align and do not over tighten the mounting bolts so that the cooler would be
damaged While the oil cooler is removed. the oil lines should be disconnected and flushed
c
If it is found that oil is leaking around the line compression nuts. check that the nuts are tightened
to 125 inch pound wet torque or the nut max be backed off. retightened finger tight. plus a 3 4 turn Do
not oxer torque.
d
Should oil continue to leak. it max be necessary to replace the seal rings Also remove the
compression nuts and inspect the line ends in the area of the swagged ferrules for collapsed tubing This
condition max be observed bx looking into the tubing ends Should the tubing show indications that it is
collapsed and new seal rings and proper torque does not stop leakage. the oil lines should be replaced Alo
inspect the surfaces of the mating fittings for damage
ISSUED: 8/18/72
POWER PL
PIPER COMANCHE SERVICE MANUAL