Magnetos; Internal Timing; Installation And Timing To Engine - Cessna T182 Series Service Manual

MODEL 182 & T182 SERIES SERVICE MANUAL
11-73. MAGNETOS.
NOTE
11-74. DESCRIPTION. The magnetos contain a con-
As the magneto is removed from its mount-
ventional two-pole rotating magnet (rotor), mounted
ing, be sure that the drive coupling rubber
in ball bearings. Driven by the engine through an
bushing and retainer do not become dislodged
impulse coupling at one end, the rotor shaft operates
from the gear hub and fall into the engine.
the breaker points at the other end of the shaft. The
nylon rotor gear drives a nylon distributor gear which 11-76. INTERNAL TIMING.
transfers high tension current from the wedge-mount-
a. Whenever the gear on the rotor shaft or the cam
ed coil to the proper outlet in the distributor block. (which also serves as the key for the gear) has been
A coaxial capacitor is mounted in the distributor block removed, be sure that the gear and cam are installed
housing to serve as the condenser as well as a radio
so the timing mark on the gear aligns with the "O"
noise suppressor. Both nylon gears are provided
etched on the rotor shaft
with timing marks for clockwise or counterclockwise b. When replacing breaker assembly or adjusting
rotation. The distributor gear and distributor block contact breaker points, place a timing pin (or 0. 093
have timing marks, visible through the air vent holes, inch 6-penny nail) through the timing hole in the bot-
for timing to the engine. A timing hole is provided
tom of the magneto next to the flange and into the
in the bottom of the magneto adjacent to the magneto mating hole in the rotor shaft. Adjusting contact
flange. A timing pin or 6-penny nail can be inserted breaker points so they are just starting to open in
through this timing hole into the mating hole in the
this position will give the correct point setting.
rotor shaft to lock the magneto approximately in the
Temporarily assemble the magneto halves and cap-
proper firing position. The breaker assembly is
acitor slip terminal and use a timing light to check
accessible only after removing the screws fastening that the timing marks, visible through the ventilation
the magneto halves together and disconnecting the
plug holes are approximately aligned.
capacitor slip terminal. Do not separate magneto
halves while it is installed on the engine or internal
NOTE
timing may be disturbed.
The sideof the magneto with the manu-
11-75. REMOVAL.
facturer's insignia has a red timing mark
a. Remove engine cowling in accordance with para-
and the side opposite to the insignia has
graph 11-3.
a black timing mark viewed through the
b. Tag for identification and remove high tension
vent plug holes. The distributor gear
wires from the magneto being removed.
also has a red timing mark and a black
on the engine. Do not place red and black
The magneto is in a SWITCH ON condition lines together on the same side.
when the switch wire is disconnected. Re-
move the high tension wires from magneto c. Whenever the large distributor gear and rotor
or disconnect spark plug leads from the gear have been disengaged, they must be engaged
spark plugs to prevent accidental firing. with their timing marks aligned for correct rotation.
Align the timing mark on the rotor gear with the
c. Disconnect switch wire from condenser terminal "RH" on the distributor gear. Care must be taken to
at magneto. Tag wire for identification so it may be keep these two gears meshed in this position until
installed correctly. the magneto halves are assembled.
d. Rotate propeller in direction of normal rotation
until No. 1 cylinder is coming up on its compression 11-77. INSTALLATION AND TIMING TO ENGINE.
stroke.
The magneto MUST be installed with its timing
marks correctly aligned, with the number one cylin-
NOTE
der on its compression stroke and with number one
piston at its advanced firing position. Refer to para-
To facilitate the installation of a replacement
graph 11-12 for the advanced firing position of num-
magneto, it is good practice to position the
ber one piston.
crankshaft at the advanced firing angle for
No. 1 cylinder during step
"d."
Any standard
timing device or method can be used, or if the
magneto being removed is correctly timed to
the engine, the crankshaft can be rotated to a The magneto is grounded through the ignition
position at which the breaker points will be switch, therefore, any time the switch
just opening to fire No. 1 cylinder.
(primary) wire is disconnected from the
magneto, the magneto is in a switch ON or
e. Remove magneto retainer clamps, nuts and HOT condition.
Before turning the propeller
washers and pull magneto from crankcase mounting by hand, remove the high tension wires from
pad.
the magneto or disconnect all spark plug leads
to prevent accidental firing of the engine.
Revision
1 1-25