Piper Navajo PA-31 Service Manual page 497

ing of main contact points at E gap set-
ting (15
°
± 2°).
226
c. The retard
contact assembly
of
the dual-breaker magnetos
may be
timed as follows:
1. The retard
contact assembly
is adjusted
to open a predetermined
number of degrees after the main con-
tact assembly
opens.
The degree of
retard
for any particular
magneto is
stamped
in the bottom of the breaker
compartment.
2. Locate the exact point of main
contact
assembly opening and set the
11-8149 Pointer Assembly
over the 0
°
mark on the 11-8693 Timing Plate As-
sembly.
Turn rotating magnet
in the Figure 8-13.
Aligning Timing Marks
direction of normal rotation until point-
Single Contact Assembly
Magneto
er indexes with the degree
of retard.
Tighten adjusting
knob of 11-8465 Holding Tooland 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 turn rotating magnet until cam follower is on
high point of cam lobe.
Contact clearance
shall be 0.016 ± 0.006 inch.
If dim-
ension is not within limits,
re-adjust
contact assembly and recheck
to be sure
that points will open within retard degree tolerance.
Remove the 11-8150-1 Tim-
ing Kit and two studs from the magneto.
d. If the distributor
block was not removed
from the housing, the internal
timing may be checked by turning
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 magnetos 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
magnet in direction
of rotation until it is located in fir-
ing position (keyway up and main points just opening).
Tighten adjusting
knob of
11-8465 Rotor HoldingTool.
Apply alight coatingof
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.
Reissued: 10/12/79
POWER PLANT
PIPER NAVAJO SERVICE MANUAL
2123