Section VIII. ORGANIZATIONAL MAINTENANCE PROCEDURES
3-53. Inspection and Test
3-52. General
All inspection and test requirements outlined in
The instructions in this section, and all subsequent
maintenance allocation chart for organizational level are
paragraphs and sections, are published for the
covered in the paragraphs describing other maintenance
information and guidance of organizational maintenance
procedures within the system.
personnel in maintaining the crane-shovel.
Section IX. ENGINE CYLINDER HEAD AND VALVE MECHANISM
leaks, then add engine oil to crankcase, if necessary
3-54. General
(LO 5-3810-206-12).
a.
Model 687C-18-ES Engine. On this two
b.
Removal and Installation, Model DSSSTA
cycle diesel engine the cylinder head forms the top of
Engine.
the combustion chamber and contains passages for the
(1) Remove the six bolts, flatwashers, and
intake of air and the expulsion of gases. The exhaust
seals that secure valve cover to cylinder head; remove
valve mechanism is attached to the head. The rocker
valve cover, and inspect gasket.
arm, which directly operates the exhaust valve, operates
(2) Replace a defective gasket seal, then
on a short shaft mounted in two supports on the cylinder
carefully install valve cover. Be sure gasket fits recess
head. Valve lash adjustment is accomplished with the
in valve cover, then install six seals in top of valve
adjustable ball-ended screw in the rocker arm.
cover; position flatwashers on bolts, install bolts through
b.
Model DSSSTA Engine. On this four cycle
seals, and tighten to between 12 and 18 foot pounds
diesel engine the valves and valve mechanism admit
inlet air and release exhaust gases at precisely timed
(3) Start engine (para 2-10) and run until
intervals during engine operation. The inlet valve is
engine reaches operating temperature, checking for oil
open during intake stroke of piston to permit air to enter
leaks at gasket and seals. Stop engine (Para 2-11),
cylinder. After the power stroke, the exhaust valve is
correct any leaks, then add engine oil to crankcase if
opened to permit piston to force burned gases from the
necessary (LO 5-3810-206 12).
cylinder as it moves upward in the exhaust stroke.
c.
Differences. There are other changes in
3-56. Valve (Rocker Arm) Adjustment
configuration between the two engines, in addition to
quantity of valves and stroke cycles, which will be
a.
General. The valve adjustment may be
covered in the applicable maintenance paragraphs.
accomplished with engine hot or cold. But when
adjusted cold, final adjustment must be made while hot.
3-55. Valve Cover and Gasket
These instructions will cover valve adjustment on a hot
engine (water temperature between 160F and 180F).
a.
Removal and Installation, Model 687C-18-ES
b.
Model
687C-18-ES
Engine
Valve
Engine.
Adjustment.
(1) Turn three locking hand-wheels securing
(1) Remove valve cover (para 3-55).
cover counterclockwise until they are loose, then
remove valve cover from cylinder head.
(2) Start engine (para 2-10) and run until
operating temperature is reached (between 160 and
(2) Remove valve cover gasket from
180F).
cylinder head (or cover) and discard.
(3) When
engine
is
at
operating
(3) Install new valve cover gasket on
temperature, stop engine (para 2-11), with cylinder No. 1
cylinder head; position valve cover on gasket, then
at top dead center (valve seated closed). Use wrench
secure by turning the three locking hand-wheels
clockwise until they are tight.
screw.
(4) Start engine (para 2-10), run until
(4) Use screw driver and turn adjusting
engine reaches operating temperature, checking for oil
screw until a clearance of 0.012 inch (hot) to 0.014 inch
leaks at gasket. Stop engine (para 2-11); correct any
(cold) is obtained with thickness gauge.
3-47
