Piper COMANCHE PA-24-180 Service Manual page 474

7C-61. Inspecion And Claig
Of Spark hg.
L Viaully inspect eah spark plug for the following non-repainble defec:
1. Severely damed sheD or shield threads nicked up, stripped or aomhbreded.
2. Badly battered or rounded d e hexgons.
3. Outof-round or damed
shielding brrel.
4. Chipped crucked, or broken ceamic insultor poRonr.
5.
Bdly eroded electrode worn to approxnimtey 50% of origina size.
b. Clean the spark plug as required removing carbon and foreiF depois.
c. Test he spark plug both eclcrically and for reisance.
d.
Set the decrode gsp t .016 ± .1 of an inch or if a smoother operaion at idle speed and reduced
magneto dropoff is dere, set at .018 to .022 of an inch. However, with wide pp seting the plugs must be
erviced at more frequent intervas. Fine wire plainum or iridium elecrodes should be set t .013 to .018
of
an
inch only.
7C62. Insallaio Of Spark Phlu. Before instlling spark plugs, ascertr at the threads within the
cylinder re clean and nor damaed.
L
Apply anutseize compound sparingly on the threads and install gaket and spark plugs. Torque 360
to 420 inch pounds.
CAUTION
Make certain the deep socket is propery seated on the spark plug
hexagon as damage to the plug could result if the wrench is cocked to
one side when pressure as applied.
b. Carefully insert the terminal insulator in the spark plug and tighten the coupling nut.
7C-63. Lubricaion System.
7C-64. Oil Pressure Relief Vave. The adjustable i) pressure relief valve enables the operator to maintain
engine oil pressure within the specified limis (refer to the engine manufacturer's appropriate manual). The
valve is located above and to the rear of No. 5 cylinder. If the pressure under normal operating conditions
should consistently exceed 90 psi, or run less than 60 psi, adjust the valve as follows.
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, back off the adjusting screw one or
two full urns. If pressure is too low, turn adjusting screw further into the relief valve plug. therebv
increasing the rension on the relief valve spring. When the valve has been satisfactorily adjusted. lockwire
the crown nut to the drilled ear proJecring from the valve mounting boss. The engine has a thermostatic
bypass valve as a safey feuture. The valve will open should the temperannre exceed a safe operating level
and allow the oil to circulate in the system to avoid permanent damage to the engine.
POWER PLANT
ISSUED: 8/18/72
2 H20
PIPER COMANCHE SERVICE MANUAL