Piper COMANCHE PA-24-180 Service Manual page 385

7A-77 Removal Of Harness.
a.
Disconnect the clamps that secure the wires to the engine and accessories.
b
Loosen the coupling nuts at the spark plugs and remove the insulators from the spark plug barrel
well Use caution when withdrawing the insulator not to damage the insulator spring
c. Place a guard over the harness insulator.
d.
Remo\e the harness assembly terminal plate from the magneto.
e Remoxe the engine baffle plate that receives the harness asembly
f. Remoxe the harness from the airplane
7A-78. Installation Of Harness. Before installing harness on magneto. checking mating surfaces for
cleanliness. Spray entire face of grommet with a light coat of Plastic Mold Spary. SM-O-O-TH Silicone
Spray or equivalent. This will prevent harness grommet from sticking to magneto distributor block.
a.
Place the harness terminal plate on the magneto and tighten nuts around the plate alternately to
seat cover squarely on magneto Torque screws to 18 to 22 inch pounds.
b Route ignition wires to their respective cylinders
c Clamp the harness assembly in position and rep'.
the engine baffle plate
d Connect the leads to the spark plugs
7A-79 Spark Plugs.
7A-80 Removal Of Spark Plugs.
a.
Loosen the coupling nut on the harness lead and remove the terminal insulator from the spark plug
barrel well
NOTE
When withdrawing the ignition cable lead connection from the plug
care must be taken to pull the lead straight out and in line with the
center line of the plug barrel. otherwise. a side load will be applied
which frequently results in damage to the barrel insulator and
connector If the lead cannot be removed easily in this matter. the
resisting contact between the neoprene collar and the barrel
insulator will be broken by a rotary twisting of the collar. Avoid
undue distortion of the collar and possible side loading of the barrel
insulator
b.
Remove the spark plug from the engine. In the course of engine operation. carbon and other
combustion products will be deposited on the end of the spark plug and will penetrate the lower threads to
some degree As a result. greater torque is frequently required for remoing a plug than for its installation
Accordingly. the torque limitations given do not apply to plug removal and sufficient torque must be used
to unscrew the plug. The higher torque in removal is not as detrimental as in installation. since it cannot
stretch the threaded section. It does. however. impose a shearing load of this section and may. if sufficiently
severe. produce a failure in this location
ISSUED: 8/18/72
2E3
POWER PLANT
2E3
PIPER COMANCHE SERVICE MANUAL