The following instructions, Engine/Alternator Mating, must be followed to ensure proper alignment and en- gine crankshaft endplay.
Failure to follow these instructions can result in serious damage to the engine and/or alternator.
ENGINE/ALTERNATOR MATING
Before attaching the alternator to the engine it is essen- tial the axial end play and axial alignment of the crank- shaft be maintained within limits. (Refer to Table I.) This will prevent possible thrust washer failure due to insuf- ficient crankshaft end play and assure alternator to engine alignment to avoid placing an overstress con- dition on the rear main bearings, flywheel housing adapter and flex coupling.
This procedure is to assure that crankshaft and alter- nator end play will remain within specification and the rotor and stator frame will be in alignment with the crankshaft.
Alternator Measurement
1. Thoroughly clean the alternator housing frame face and the rotor drive adapter face.
2. With the alternator in a horizontal position, place a level on the alternator housing and block it so housing is level.
3. Install a piece of bar stock over rotor drive adapter and attach each end to alternator housing using two 5/8 - 11UNC Capscrews (Figure 4-3). a. Alternately tighten the two capscrews, moving
the rotor to the rear of the housing. Do not exceed 12 ft. lbs. (16 N.m) torque.
b. Relax pressure on rotor by carefully removing the two capscrews in the bar. Remove the bar. 4. Mount a machinist’s parallel bar across the rotor drive adapter (Figure 4-4) and measure the follow- ing:
a. Using a depth micrometer, measure distance between parallel bar and alternator housing mounting face at each end of bar. Record the readings.
b. Remove the parallell bar, rotate 90° and re-attach bar to rotor.
c. Using the depth micrometer, measure distance between parallel bar and alternator housing mounting face at each end of bar. Record the readings.
5. Average the four readings obtained in step 4; this will be measurement “A”.
FIGURE 4-3. ARMATURE CENTERING SHIMS 1. Alternator Housing
2. Drive Adapter 3. Rotor
4. 5/8 - 11 Capscrew 5. Bar Stock
FIGURE 4-4. DETERMINING MEASUREMENT "A" 1. Alternator Housing
2. Rotor Drive Adapter 3. Parallel Bar
Engine Endplay Measurement
NOTE: Loosen or remove engine fan belt prior to measuring crankshaft endplay.
1. Place dial indicator on flywheel housing adapter with dial pointer on flywheel face. (Refer to Figure 4-5.)
a. If available, remove front crankshaft pulley and vibration dampener and install tool for prying crankshaft forward and backward.
b. If above tool is not available, an engine side plate cover can be removed and a bar used to pry the crankshaft forward and backward. This method does not require removal of the pulley or vibration dampener. Use caution to prevent internal engine damage or entrance of dirt.
Do not pry on vibration dampener!
2. Pull crankshaft toward front of engine as far as crankshaft bearings will allow it to move. Hold crankshaft in this position and set dial indicator at “0" reading.
3. Push crankshaft toward rear of engine, read total bearing movement, taking two or three readings for verification.
4. Move crankshaft to half the distance of the total end play reading; this should place the crankshaft in the center of its end play.
End play measurement should be 0.005–0.018 in. (0.12–0.46 mm) for a Cummins engine. If end play is not within these specifications consult the En- gine Service Manual for service procedures.
5. With engine crankshaft in center of its end play, measure from the flywheel housing face (1, Figure 4-6) to the rotor drive adapter mating face on flywheel (2). Take four readings 90° apart and record the average of the readings; this will be measurement “B”.
Determining Shim Requirements
1. Subtract engine dimension “B” from alternator dimension “A” determined in previous steps. 2. Add 0.010 in. (0.25 mm) to result in step 1. The
result is the shim pack thickness required (Refer to Table II).
3. If the alternator reading “Measurement A” is
GREATER than the engine reading “Measure- ment B”:
Install shim pack between the alternator housing face and flywheel housing face (5, Figure 4-7). 4. If the alternator reading “Measurement A” is LESS
than the engine reading “Measurement B”: Install shim pack between armature rotor cou- pling adapter and engine coupling (6, Figure 4-8).
FIGURE 4-5. MEASURING CRANKSHAFT ENDPLAY 1. Flywheel Housing or
Adapter 2. Engine Flywheel3. Dial Indicator
FIGURE 4-6. DETERMINING MEASUREMENT "B" 1. Alternator Mounting Face
2. Rotor Drive Adapter Mounting Face
3. Engine Flywheel
Installing Alternator on Engine
1. Use the three brackets provided on the alternator for lifting. The top front lifting bracket should be equipped with some method of adjusting the al- ternator to keep it horizontal. The remaining two chains should be of equal length.
2. Install shim pack determined in previous steps. Carefully move alternator into place and engage flywheel coupling dowel pins into alternator rotor drive adapter.
3. Install four flywheel housing adapter-to-alternator housing capscrews and flat washers at 90° inter- vals, but do not tighten fully.
4. With feeler gauge, measure gap between flywheel housing adapter ring and alternator housing and adjust housing to get equal gap 360° around the adapter ring within 0.002 in (0.051 mm).
5. Install remaining capscrews, washers, and nuts. Torque flywheel housing adapter-to-alternator housing hardware (4, Figure 4-1) alternately in a crisscross pattern to 175 ft.lbs. (235 N.m) torque. 6. Install the engine flywheel-to-rotor drive ring bolts (3, Figure 4-2) and torque to 175 ft.lbs. (235 N.m).
7. If previously removed, install right and left alterna- tor-to-cradle structure. Insert pins (5, Figure 4-8) in front hole if equipped with GTA22 or rear hole if equipped with GTA26 alternator. Install keeper plates and adjusting screws and nuts. Do not tighten at this time.
8. Install alternator-to-cradle structure mounting bolts (1, Figure 4-1) and torque to 750 ft. lbs. (1017 N.m) for a Cummins engine.
9. Tighten engine-to-cradle structure mounting bolts (6, Figure 4-1) to 310 ft. lbs. (420 N.m) for a Cummins engine.
10. Equalize gap at right and left side of Engine/Alter- nator cradle structure at mounting pin (Refer to Figure 4-8):
a. Loosen jam nuts (2) and adjust set screws (3) to equalize gap within 0.06 in. (1.5 mm). b. Lock setscrews by tightening jam nuts. FIGURE 4-7. SHIM PLACEMENT LOCATION
1. Alternator Housing 2. Rotor Drive Adapter 3. Flywheel
4. Flywheel Housing or Adapter
5. Housing Shim Location 6. Flywheel Shim Location