Piper SEMINOLE PA-44-180, Maintenance Manual

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13. Rotate the entire magneto in the direction of rotor rotation until one of the timing lights just goes OFF.
Then, evenly tighten the magneto mounting clamps.
14. Back the engine up approximately 10° and then carefully “bump” the engine forward while observing the
timing lights.
15. At the No. 1 cylinder firing position the same timing light mentioned in Step 13 should go OFF. Continue
turning the engine in its normal direction of rotation until the other timing light goes OFF. This should not
be more than 3 engine degrees later than the first light.
16. Repeat Steps 12 13 and 14 until the condition described in Step 15 is obtained.
17. Complete tightening of the magneto securing clamps by torqueing to 150 inch-pounds.
18. Recheck timing once more and if satisfactory, disconnect the timing light and remove the adapter leads.
19. Reinstall plugs in timing inspection holes and torque to 12-15 inch-pounds.
20. Loosely install the harness with clamps and/or brackets.
MAGNETO TIMING PROCEDURE. (Internal Timing)
— Note —
On aircraft equipped with counter-rotating engines, the engines utilize counter-rotating
magnetos as well. Refer to the data plate on the magneto to determine magneto
rotation. As explained earlier, the “L”mark refers to left-hand or counterclockwise
rotation, and the “R “ mark refers to right-hand or clockwise rotation as viewed from
the shaft end.
1. Remove magneto cover.
2. Loosen flange clamps and remove magneto from engine.
3. Check condition of points: replace if necessary.
4. Rotate the magneto drive shaft until a main cam lobe touches the follower of the left main breaker assembly
and adjust the breaker points to an initial opening of .016 inch. Wire feeler gauge is recommended.
5. Adjust right main breaker contact assembly to an initial point opening of .016 inch just as in Step 4.
6. Fixed contact support may be bent to adjust clearance. If support is bent, main breaker contact must be
rechecked. Torque breaker securing screws to 20-25 inch-pounds.
— Note —
Bend bracket carefully. Do not correct by bending back y bent too much; this
weakens the bracket.
7. Position rotor so keyway is at 12 o’clock position and red painted distributor teeth are visible in timing
windows.
8. Loosen drive shaft nut and position the Rotor Holding Tool(Bendix P/N 11-8465)under washer or bushing
on drive end of rotor shaft with clamp at 4 o’clock position so any shaft deflection caused by clamping
action will be in a plane parallel to breaker contacts. Tighten nut to secure holding tool to shaft. Check to
insure proper location of keyway and tighten adjusting screw of holding tool to lock rotor in position.
9. Loosen rotor holding tool and turn magnet in direction of rotation until adjacent “R” or “L” (“E” gap) mark
is aligned with pointer and lock in position. Both red painted teeth should be approximately centered in
timing windows.
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
7 4 - 11 - 0 3
Page 74-09
Revised: May 15, 1989
3G2
PIPER AIRCRAFT