8-28. REASSEMBLY OF MAGNETOS. (4200 series) (Refer to Figures 8-10 thru 8-13.)
—NOTE—
Before using the slick T-100 assembly and timing tool, it will be
necessary to align the index plate (bottom of tool) to number 67 to time
the magneto. (Refer to Figure 8-10.)
a. Loosen the screws and align number 67 with the mark on the base of tool.
b. Tighten screws and check alignment. Reverse the tool.
c. Place the frame on the T-100 assembly and timing tool. Insert the coil into the frame, making sure that it is
back against the stops. Insert the coil wedges between the bridge and the frame.
d. Drive the two wedges tight, using a hammer and flat punch. Attach the white ground wire of the coil to
the frame, using screw and lockwasher. Torque to 20 in. Ibs.
e. Check the vertical portion of the high tension lead of the coil, making sure it protrudes 1/16" beyond the
face of the frame. This provides spring pressure against the thrust bearing in the distributor block.
timing tool. Assemble both ball bearings on the rotor shaft, making sure the grease shield of each bearing is
toward the magnet. Place the rotor shaft into the base plate, threaded end down. (See Figure 8-11 .) Using
bearing assembly plug (T-101), turn the T-screw down until both bearings are seated tightly against the shoulder
on the rotor shaft. Remove the base plate (T-117) and adapter plate bushing (T-119).
g. Assemble the bearing retaining washer into the frame, raised side against the frame. Place the loading
spring into the bearing plate flat side down.
h. Assemble by hand, the rotor shaft with bearings (cam slot end) into the bearing plate making sure it is
square on the bearing.
(Refer to Figure 8-11.) Install bearing plate clamp on bearing plate and install screw and lockwasher. Torque to
20-24 in. Ibs.
j. Reverse the magneto on the T-100 assembly and timing tool so the flange of the magneto is facing up.
k. Lubricate the oil seal with light grease and assemble the seal over the end of the rotor shaft. Using oil seal
assembling plug (T-103), turn the T-screw to press the seal flush with the frame of the magneto.
l. Assemble the Woodruff key into the key slot of the rotor shaft.
m. Install the impulse coupling assembly on the shaft, and tighten the nut. Torque to 120 to 300 in. Ibs., so
the coupling is properly seated on the taper shaft and install cotter pin. Check to see if the coupling is free by
snapping it through 3 or 4 times.
—NOTE—
It will be necessary to wait until the magneto is timed before installing
the gear. Then install cotter pin.
n. Assemble the contact point kit on the bearing plate using screws from the kit. Insert the cam in the cam
slot with a screwdriver blade, and tap with a light hammer. Drive the cam all the way to the bottom of the cam
slot. Apply M-1827 cam grease sparingly to each lobe of cam before reassembly.
o. Assemble the rotor gear onto the rotor, making sure the key slot of the gear fits into the cam slot of the
rotor. Tap with a light hammer until the gear bottoms on the shaft.
p. To time the magneto internally, place the magneto on the T-100 assembly and timing tool base, making
sure the coupling lugs are in the slots of the index plate. Swing the frame counterclockwise against the pin which
will line up the rotor and cam for "E" gap position.
PIPER AIRCRAFT
PA-28-161 CADET
AIRPLANE MAINTENANCE MANUAL
Issued: FEBRUARY. 28, 1989
POWER PLANT
1J23
