Piper Aircraft Corporation Cherokee 140 PA-28-140, Service Manual

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PIPER CHEROKEE SERVICE MANUAL
01/31/08 VIIIA - POWER PLANT (PA-28R)
3B11
line on the distributor block should line
up between the L and LB marks on the
gear. On single contact magnetos the line
should favor the L mark, if possible.
d. If the distributor block was removed
from the housing, the distributor gear
alignment and internal check may be
accomplished as followed:
1. Turn rotating magnet in direction of
rotation until it is located in firing
position (keyway up and points just
opening). Tighten adjusting knob of
11-8465 Rotor Holding Tool. Apply
a light coating of Bendix Grease
P/N 10-27165 to teeth of distributor
gear, if needed. The large distributor
gear incorporates four timing marks,
L and LB for left hand rotation and
R and RB for right hand rotation.
2. With distributor gear assembled to
block, turn gear until raised rib on block lines up between the L and LB marks. Assemble
block and gear into housing, meshing the distributor gears together. The rib should favor the L
mark, if possible. (Refer to Figure 8A-13.)
3. Secure distributor block to housing with studs and washers. Tighten studs finger tight. Loosen
the 11-8465 Rotor Holding Tool and turn rotating magnet in reverse direction of rotation until
timing light indicates contact assembly had just opened and check to make certain timing
marks align within tolerance indicated above. Tighten block securing studs, first to 4-8 inch
pounds torque and then final torque to 20 inch pounds.
4. Insert the tip of your small finger through timing hole in housing and against large distributor
gear teeth. Rock distributor gear back and forth slightly. There must be perceptible backlash
between teeth of large and small gears. This check should be made at three different points,
120° apart on gear. If backlash is not evident, replace large distributor gear.
5. Install the breaker cover and complete reassembly of the magneto. Refer to the manufacturer’s
publications for complete disassembly and reassembly procedures.
e. On the magneto employing the impulse coupling, check clearance between each flyweight and each
stop pin as follows:
1. Bend the end of a stiff piece of wire into a right angle 1/8 inch long (maximum).
2. Hold magneto as shown in Figure 8A-14. Pull heel of flyweight outward
Figure 8A-13. Aligning Timing Marks