TM-5-4310-389-14
4-4 GENERAL NOTES ON ENGINE REPAIR.
a.
The front end of the engine is understood to be the end opposite the flywheel and the other engine faces are
designated accordingly. Thus, cylinder number 1 is at the rear end (at the flywheel end). The cylinder numbers
are applied to the crankcase, below the cylinder seating area. The sense of rotation of the engine is
counterclockwise, when facing the flywheel.
b.
The parts of the crankshaft assembly, timing gear, cylinders, pistons, and cylinder heads should be numbered in
sequence unless they are already marked. The numbering should commence at the flywheel end.
c.
For precision workmanship and repair, procedures should be performed in clean and neat surroundings. As the
parts are dismantled, place them where they will not get damaged. Components that are subject to wear should
be kept apart and should be individually gauged. If the low tolerances are exceeded, the components must be
replaced or rectified. In any case, fit new gaskets, packing, and 0-seals.
d.
Should bearing or pistons be damaged, the crankshaft and connecting rods should be inspected for cracks, if
possible, by the magnaflux testing method. It is important that the cause of the damage be established. Testing,
repairs, and/or reworking can be undertaken by the manufacturers or their appointed repair shops.
e.
For the repair work to be carried out on the removed engine, mounting on a swiveling assembly stand, special
fixture 003-0453 is recommended.
4-5 GENERAL NOTES ON COMPRESSOR REPAIR.
a.
Normally, the valves should be cleaned every 750 to 800 operating hours.
b.
Should the valves exhibit excessive wear and the valve seats are impaired, the valves must be replaced.
c.
Always replace the valves as a set.
d.
Observe the following instructions in valve maintenance.
1. Carefully clean the dirty valves. Never use a sharp tool for this purpose. Soak the valves in an ultrasonic
cleaner and clean with a soft brush.
2.
Observe the correct sequence when fitting together.
3.
Check individual components for excessive wear. If the valve seat and valve discs are dented, replace the
valves.
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