Rockwell Commander 112 - Alternator; Engine Change; Fuel Pump; Removal

ROCKWELL
COMMANDER
112/B/TC/TCA
MAINTENANCE MANUAL
SECTION IV
POWER PLANT
AND PROPELLER
possible damage. Inspect all connections to the start-
er solenoid, ignition switch, and battery, including
all ground connections. Clean and tighten all connec-
tions as required. Connect a jumper lead around any
switch
suspected of being defective. If the starting
system functions properly using a jumper, repair or
replace the bypassed switch. If the battery, wiring,
and
switches are satisfactory and the engine is known
to
be functioning properly, remove the starter and
send to an authorized repair station for repair.
REMOVAL. To remove the starter from the engine,
proceed as follows:
a. Remove
upper and lower engine cowling.
b. Disconnect
electrical lead from starter terminal.
c. Remove bolt attaching alternator support strut
to starter.
d. Remove nuts and washers from studs holding
starter mounting flange.
e. Remove aft inboard, and forward outboard studs
from starter mounting flange.
mST ALLATION
a. Align starter mounting flange with engine pad
studs and install attaching hardware.
b. Torque bolt and nuts to 150-inch pounds.
c. Connect electrical wires to starter.
d. Check starter operation.
e. Install cowling.
ALTERNATOR
A 14-volt, 70-amp alternator is installed on the for-
ward lower right side of the engine. The alternator
employs a 3- phase stator winding in which the phase
windings
are electrically 120 degrees apart. The
rotor consists of a field coil encased between two,
4-poled interleaved sections, producing an 8-pole
magnetic field with alternate North and South poles.
When the rotor rotates inside the stator, an alterna-
ting current is induced in the stator windings. This
-ac current is rectified,Le., changed to dc, by silicone.
diode
rectifiers and delivered to the output terminal
of the alternator. A ram air blast tube extending
from the slip ring cover of the alternator to the for-
ward engine baffle supplies cooling air to the alterna-
tor. A belt from the alternator pulley, to a pulley
which
is integral with the aft propeller flange, drives
the alternator at 3.25 times the speed of the engine.
Proper alternator belt tension should be maintained
to provide
satisfactory service (see Lycoming Service
Instructions Number 1129A). For additional informa-
tion concerning the alternator system, refer to Sec-
tion X.
REMOVAL. To remove the alternator from the engine,
proceed as follows:
a. Remove
upper and lower engine cowling.
b. Disconnect
electrical wires from alternator and
tag for identification.
c. Loosen nut attaching alternator mounting flanges
to engine.
d. Remove bolt and
washer from alternator idler
arm.
e. Rotate alternator to free belt from drive pulley.
f. Remove nuts,
washers and bolts securing alter-
nator to engine and lift alternator from engine.
mST AL LAT ION
a. Position alternator with drive belt seated in
alternator and starter ring gear pulleys.
b.
Install alternator flange mounting hardware,
but leave alternator free to rotate at flanges.
c. Install bolt and washer in alternator idler arm
and tighten belt per Lycoming Service Instruction
Number 1129A).
d.
Tighten nuts installed in step b.
e. Connect electrical wiring.
f. Install cowling.
FUEL PUMP
A diaphragm type, self regulated pressure pump is
installed on the aft lower left side of the engine acces-
sory housing. This engine operated pump provides a
continuous flow of fuel to the engine without
pressure
variations. The pump design allows the auxiliary
pump to move fuel through it to the engine in the event
it becomes inoperative and also for the purpose of
initial engine starting. If the pump becomes inopera-
tive, do not attempt to repair it. Remove the pump
and
install a new one.
REMOVAL
a. Remove upper and lower engine cowling.
b. Remove two capscrews attaching fuel pump.
c. Remove pump and gasket.
INST ALLATION
a. Clean engine accessory pad.
b. Install new pump and gasket on accessory pad.
Assure pump plunger is up to engage push rod or
drive shaft will bend.
c. Install two capscrews and torque to 300 inch-
pounds.
d. Replace cowling.
ENGINE CHANGE
REMOVAL
MODELS 112/B. The engine mount (Figure 4-10) can
be removed with the engine, if deSired. If the engine
is being returned to the manufacturer or will not be
operated within a seven day period comply with storage
instructions contained in Section II. In the following
instructions, the engine is being removed from the
mount.
4-19
Copyright Commander Owners Group 2013 All Rights Reserved
**unofficial copy**