Piper Arrow IV Turbo Maintenance Manual page 640

4. If the distributor block was removed from the housing, the distributor gear alignment and internal
check may be accomplished as follows:
A. 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.
B. 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 74-26.)
C. 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.
D. 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.
E. Install the breaker cover and complete reassembly of the magneto. Refer to the manufacturer's
publications for complete disassembly and reassembly procedures.
5. On the magneto employing the impulse coupling, check clearance between each flyweight and each
stop pin as follows:
A. Bend the end of a stiff piece of wire into a right angle 1/8 inch long (maximum).
B. Hold magneto as shown in Figure 74-27. Pull heel of flyweight outward with the hooked wire and
make certain that feeler gauge of 0.010 inch minimum thickness will pass between stop pin and
the highest point of the flyweight.
A true and accurate check of the clearance between flyweight
and stop pin can only be obtained by pulling the flyweight
outward as described above. Do not attempt the check by pushing
in on flyweight at point "A. "
6. Install and time magneto, removed from engine, in accordance with Installation and Timing Procedure
(Timing Magneto To Engine).
7. Secure external switch leads to the breaker cover terminals. Connect harness assembly to the magneto.
Effectivity
PA-28RT-201
PIPER AIRCRAFT
PA-28RT-201 / 201T
MAINTENANCE MANUAL
—NOTE—
3E12
74-11-03
Page 74-27
December 1, 1978