Magneto Installation Timing Procedure - Piper PA-44-180 SEMINOLE Maintenance Manual

8. Check the capacitors for looseness in the magneto cover of the harness assembly and for any physical
damage. Using a Bendix 11-1767-1, -2 or -3 condenser tester or equivalent, check capacitors for
capacitance, series resistance and leakage. Capacitance shall be 0.34 to 0.41 microfarads.
9. Check magneto to engine timing per instructions given in the following paragraph.
10. Check action of impulse coupling. With the ignition switch off, observe breaker cam end of r.otor while
manually cranking the engine through a firing sequence. The rotor should alternately stop and then (with an
audible snap) be rotated rapidly through a retard firing position. If impulse action is not correct, remove the
magneto for overhaul.
MAGNETO INSTALLATION AND TIMING PROCEDURE. (Timing Magneto to Engine)
1. Installation of the magneto to the engine may be accomplished without removal of the cover from the
magneto. Also, the magneto cover has switch terminal outlets for the right and left sides of the magneto
located in the center of the harness lead outlet sections of the cover.
2. The magneto incorporates a built-in pointer and a degree wheel with sufficient reference to assist the
mechanic in magneto timing procedures. Printed upon the rotating magnet are marks to indicate magneto
neutral and magneto "E" gap (8°). (Refer to Figure 74-5.) Also included are retard angle references of 15,
20 and 25 degrees. These marks are set up for either clockwise (R) or counterclockwise (L) rotation of the
magneto as viewed from the magneto drive end. The timing tooth of the large distributor gear is marked
with red paint. (Refer to Figure 74-6.)
3. When correctly timed internally, a magneto will have the timing teeth of the large distributor gears
approximately centered in the timing windows, the R or L ("E" gap) mark on the rotor in alignment with the
pointer and both main breaker points opening, all occuring simultaneously. These three references, "E" gap,
painted teeth and point opening, are all used when timing the magneto to the engine.
4. Remove the spark plug from the No. 1 cylinder and turn the crankshaft in the direction of normal rotation
until the compression stroke is reached.
5. Continue turning the crankshaft until the 23° advance timing mark is in alignment with the small hole
located on the top face of the starter housing at the two o'clock position. (Refer to Figure 74-3.)
6. Install the magneto-to-engine gasket on the magneto flange.
DO NOT AT TACH HARNESS SPARK PLUG ENDS TO THE SPARK PLUGS
UNTIL AN MAGNETO TO ENGINE TIMING PROCEDURES AND
MAGNETO-TO-SWITCH CONNECTIONS ARE ENTIRELY COMPLETED
The use of a timing light, unit Part No. 11-9110 or 11-9110-1 will simplify the timing
procedure. This unit is availablefrom theBendix Corporation, Sidney, New Yo r k
13838.
It is recommended that short adapter leads be fabricated to facimate connecting the
timing light unit to the switch outlet terminals of the cover. (Refer to Figure 74-4.)
PIPER AIRCRAFT
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
— WARNING —
— Note —
3F22
7 4 - 11 - 0 2
Page 74-05
Revised: May 15, 1989