TURBOCHARGER GP 2967644 - Caterpillar

Cranking Motors
30-MT, 35-MT, 40-MT, 50-MT Series
Figure 1-Typical 50-MT Series heavy duty cranking motor.The heavy duty cranking motors covered in this bulletin have a shift lever and solenoid plunger that are totally enclosed to protect them from exposure to dirt, icing conditions and splash. The nose housing can be rotated to obtain a number of different solenoid positions with respect to the mounting flange, which is a feature that makes these motors universally adaptable to a wide variety of different mounting applications.Positive lubrication is provided to the bronze bushings by an oil saturated wick that projects through the bushings and contacts the armature shaft. Oil can be added to each wick by removing a pipe plug which is accessible on the outside of the motor.Available as an optional feature are oil reservoirs for the bronze bearings which makes available a larger oil supply thereby extending the time required between lubrication periods. Another optional feature is "O" rings which can be added to resist entry of dirt and moisture into the entire motor assembly. When the oil reservoirs and "O" rings are included, the motor will provide long periods of attention-free operation.Many models feature a seal between the shaft and lever housing and all models have a rubber boot or linkage seal over the solenoid plunger. The seal and the boot, when used together, prevent entry of oil into the motor main frame and solenoid case, allowing the motor to be used on wet clutch applications.Four kinds of clutches, a heavy duty sprag, a Positork drive, an intermediate duty type and a splined drive, may be used with enclosed heavy duty type cranking motors. All four types are moved into mesh with the ring gear by the action of the solenoid. The pinion remains engaged until starting is assured and the solenoid circuit is interrupted. In case of a butt engagement with the heavy duty sprag clutch or Positork drive, the motor will not be energized to prevent damage to the pinion and gear teeth. The spline drive is normally used on gas turbine applications, and can be engaged into the turbine spline gear before the turbine gear has coasted to a stop.
Figure 2-Cross-sectional view of motor with DR-250 heavy duty drive (50-MT). (Some models use heavy duty sprag clutch illustrated in Figures 14 and 15.)Maintenance
Under normal operating conditions, no maintenance will be required between engine overhaul periods. At time of engine overhaul, motors should be disassembled, inspected, cleaned, and tested as described in succeeding paragraphs.Adjustable Nose Housing
Two methods are employed to attach the nose housing to the lever housing. As shown in the cross-sectional views of Figure 2, Figure 3, and Figure 4, one method attaches the nose housing to the lever housing by means of bolts located around the outside of the housing. To relocate the housing, it is only necessary to remove the bolts, rotate the housing to the desired position, and reinstall the bolts. The bolts should be torqued to 13-17 lb. ft. during reassembly. In