Piper COMANCHE PA-24-180 Service Manual page 468

FIGURE 7C-10. ROTOR HOLDING TOOL
FIGURE 7C-11. TIMING KIT INSTALLED
INSTALLED
c. The retard contact ssembly of the dual-breaker magnetos may be timed as follows:
1. The retard contact uembly is adjused to open a predeermined number of degrees after the
main conuact aembly opens. The degree of reard for any particular mgneo is sumped in the bottom of
the breaker comparrment.
2. Locate the exact point of main contact assembly opening and se the 11-8149 Pointer
Assembly over the 0 mark on the 114693 Timing Plate Assembly. Turn routing magnet in the directon
of normal roation until pointer indexes with the degree of retard. Tighten adjusing knob of 11-8465
Holding Tool and set retard contact assembly to just open. within 2° -0 . Tighten securing screws to
20-26 inch pounds. Loosen adjusting knob of holding tool and rumrn rotating magnet until cam follower is
on high point of cam lobe. Contact clearance shall be 0.016 ± 0.006 inch. If dimension is not withm limits,
re-adjust contact assembly and recheck to be sure that points will open within retard degree tolerance.
Remove the 11-8150-1 Timing Kit and rwo suds from the magneto. '
d. If the distributor block was not removed from the housing, the internal timing may be checked by
urning the magneto in the normal rotation to number one firing position (keyway up and main points just
opening). At this position, the reference line on the distributor block should line up between the L and LB
marks on the gear. On single contact magneros the line should favor the L mark and on the dual contact
magnetos the line should favor the LB mark, if possible.
e. If the distributor block was removed from the housing, the distributor gear alignment and internal
check may be accomplished as follows:
1. Turn rotating magner in direction of rotation until ir is located in firing position (keyvwav up
and main 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 riming marks. L and LB for left hand rotation and R and RB for right hand rourtation.
2. With distrbutor gear assembled to block. rum gear until raised nb on block lines up between
the L and LB marks. Assemble block and gear into housing, meshing the distributor gears together. For the
dual contact assembly magneto, distributor block nb must align between painted marks. However, the nb
should favor the LB mark. if possible. (Refer to Figure 7C-12.) On the single contact magneto the rinb
should favor the L mark.
POWER PLANT
ISSUED: 8/18/72
2H14
PIPER COMANCHE SERVICE MANUAL