Piper PA-24 Comanche Service Manual page 386

PIPER COMANCHE SERVICE
MA~l':\L
With the
engine
thoroughly warmed .up and running at a ma.ximum of 1200
~P~.
observe
the r e a e
on the
011
pressure gauge.
If
the pressure
IS
above 90 pSI. stop engine. loosen the adjusting locknut: and bac
\)1' 1 '
the adjusting
screw
one or two full turns. Tighten locknut and retest. If
pressure is
too
low
turn adiustinu
screw
further into the
relief valve
plug. thereby increasing the tension on the relief
valve
spring. When th~
valve has been satisfactorily adjusted. tighten the locknut and lock wire the crown nut to the drilled car
projecting (rom the
valve mounting boss.
7A-~5.
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 the lower aft section of the sump. These screens
should be cleaned at each oil change to removeany 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 darnge.
a. To remove the pressure screen. remove oil temperature electrical lead or the temperature bulb and
the cap screws securing the housing. :\ote 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 mating surface
\)1'
the housing and accessory case for gasket panicles.
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
removed
from the sump by 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 fully into the sump. install gasket and plug. Safety the plug.
7.-\-Ro. Oil Cooler. •
a. When conducting a routine engine inspection. the oil
cootens).
lines and fittings should be
chcc
for the following:
I. Oil cooler line attachments should be examined to be certain that all are tight and there is no
indication
of eros-threading.
(See C for oil line torque.)
, Oil lines must have adequate clearance and be properly aligned.
J. Oil line supports should be tight. properly 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. properly 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 may be backed off. retightened finger tight. plus a
J
4 turn. Do
not over torque.
d. Should oil continue to leak. it may 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 may be observed by looking into the tubing ends. Should the tubing show indications that it
i,
collapsed and new seal rings and proper torque does not stop leakage. the oil lines should be replaced. Also
m..pect the surfaces of the mating fittings for damage.
ISSl"ED: 8/18/72
2E6
POWER
PL.~'