MAINTENANCE OF ENGINE
SECTION I. MAINTENANCE OF ENGINE ASSEMBLY
GENERAL. This chapter details the procedures necessary to replace, repair, overhaul, or rebuild the engine
assembly and related components as necessary.
Engine Assembly. The engine is a 12-cylinder diesel of V configuration having a displacement of 2300 cubic
inches (37. 7 liters). The engine operates on the four stroke cycle principle and has two exhaust and two
intake valves per cylinder. A turbocharger is used to increase power output by improving air induction. The
turbochargers are after-cooled to provide denser air for combustion, and to reduce exhaust temperatures.
Replaceable cartridge-type filters are provided for the fuel, lubricating, and cooling system.
Repair, Overhaul, Rebuild. These procedures employ the methods and specifications recommended by the
manufacturer for the successful overhaul of the engine components. The information is given as an addition
to the skills required by experienced service personnel. Due to the precision fit of components, all tolerance
specifications and torque values should be strictly followed. Long engine life and efficient operation depend
on the care and precision with which inspections, repairs, and adjustments are made. When performing
maintenance procedures, note the following:
The inspection area must be thoroughly dean.
The area must be well lighted.
Cover inspection tables with clean, dry paper; keep special gages and indicators in cabinet lockers
when not in use.
Close all openings that are uncovered during inspection and repair with covers, plugs, or caps.
Inspection limits set forth in this manual are manufacturing and normal wear limits. Before
condemning a part, check the specifications for operating limits with the mating part. The wear limits,
given in the Table 1-4 are satisfactory for most repair procedures. The overhaul and rebuild of
components, however, shall be carried out to new minimum or maximum tolerances where indicated.
Stationary parts with cracks, stripped bolt or stud holes, and eroded, or otherwise damaged surfaces,
may be repaired by sleeving, installing threaded inserts, or by welding or brazing. All welding or
brazing shall be performed by certified operators.
During both removal and disassembly operations, check parts and components for wear and damage
before cleaning. Fine metallic particles present in a lubricant, for example, are evidence of wear that
would be lost during cleaning operation.
Parts must be inspected in accordance with good shop practice by experienced personnel. A careful
visual inspection should precede any detailed check to eliminate unnecessary inspection procedures
and to determine the extent of further checking. Inspection requirements in this section are provided
as the basis for setting up inspection procedures.
Check all micrometers, gages, indicators, and other measuring instruments periodically. Calibrate in
accordance with MIL-STD-120 or with the applicable manufacturer's recommendations.
Good shop practice includes complete and accurate inspection records. Records not only simplify
reworking of the equipment, but also ensure a complete and thorough overhaul. Inspection records
should be based upon the requirements outlined in this section. Parts needing rework or replacement
should be so tagged, and a notation of the disposition of these parts should be entered on the
inspection records. The same method should be followed for parts needing special treatment, such as
magnetic or fluorescent inspections, painting, and similar treatments.
Descriptive terms used in this section to describe the condition of parts are defined in General Defect
Definitions, Table 9-1. Whenever these conditions exist, the inspector should refer to the dimensional
data per Table 1-4 related to the damaged part and decide if rework is feasible. The part should be
tagged accordingly and repaired or disposed of in accordance with current regulations. The disposition
of the part should then be noted on the inspection record.
Parts which are normally replaced at each overhaul should be given a brief, visual inspection.
Damage of these parts may reflect malfunction of other components in the engine. Consider this
possibility when any part has been damaged.