Piper Arrow IV Turbo Maintenance Manual page 620

REMOVAL OF MAGNETO.
1. Remove the engine cowl.
2. Disconnect the "P" lead from the magneto.
3. Remove the harness outlet plate from the magneto by removing the four attaching screws.
4. Remove the two nuts and washers securing the magneto to the engine accessory housing.
5. Pull the magneto from the engine.
MAGNETO TIMING PROCEDURE. (Internal Timing)
When installing or adjusting breaker points and before timing the magneto to the engine, it is important
that the internal timing of the magneto be correct. The recommended method of checking the internal timing of
the magneto is to use the Bendix 11-8150 Timing Kit using the procedure described in sub-paragraph 1.
H o w e v e r, if a timing kit is not available, the cast-in timing marks in the breaker housing and a fabricated
pointer may be used as described in sub-paragraph 2.
1. Check the internal timing with the Bendix 11-8150 Timing Kit using the following procedure:
A. Remove the magneto from the engine and remove the contact point cover.
B. Loosen the nut securing the drive plate to the magneto shaft sufficiently in order to install the
Bendix 11-8465 Rotor Holding Tool under the nut and flat washer as shown in Figure 74-6.
Tighten the nut enough to hold the tool securely.
C. Install the Bendix 11-8147 Plate Assembly to the breaker compartment of the magneto as shown
in Figure 74-7.
D. Remove the timing inspection plug from the top of the magneto and turn the rotating magnet in the
direction of normal rotation until the painted chamfered tooth on the distributor gear is
approximately in the center of the inspection window. Then turn it back until rotating magnet
locates in its neutral position. Tighten adjustment knob of 11-8465 Rotor Holding Tool, holding
the rotating magnet in the neutral position.
Tighten adjusting knob of rotor holding tool only enough to hold
magnet shaft firmly. Do not overtighten.
E. Install the Bendix 11-8149 Pointer Assembly on the cam screw and align pointer with the zero
degree mark on the timing plate.
F. Loosen adjusting knob of rotor holding tool and turn rotating magnet in normal direction of
rotation until pointer indexes with the respective 10° mark ("E" gap). Tighten adjustment knob of
rotor holding tool.
G. With the Bendix 11-9110 Timing Light or equivalent, adjust main breaker contacts to just open at
this position. Loosen holding tool and turn rotating magnet until breaker cam follower is on the
high point of the cam lobe. Tighten holding tool and measure contact clearance. It must be 0.018 +
0.006. If not, readjust breaker and recheck to be sure that contacts will open within "E" gap
tolerance +4°. Replace breaker assembly if "E" gap tolerances and contact clearance cannot be
obtained.
H. After timing is complete, tighten breaker securing screws to 20 to 25 inch-pounds and recheck
settings. Remove timing kit parts.
Effectivity
PA-28RT-201T
PIPER AIRCRAFT
PA-28RT-201 / 201T
MAINTENANCE MANUAL
—CAUTION—
3D16
74-11-03
Page 74-07
December 1, 1978