gine parts during the engine warm-up
Tune-Up Sequence
period. This will ensure a valve setting
that is close enough to the specified
clearance to prevent damage to the
valves when the engine is started.
Before starting an engine after an
e n g i n e speed control adjustment or
E n g i n e s With Four Cylinder Heads
a f t e r removal of the engine gover-
nor cover, the serviceman must
GENERAL. The exhaust valve bridges
determine that the injector racks
must be adjusted and the adjustment
m o v e to the no-fuel position when
screws locked securely at the time the
the governor stop lever is placed
cylinder head is installed on the engine.
in the stop position. Engine over-
The necessary adjustment procedure is
speed will result if the injector
outlined in Subsection 11B.
racks cannot be positioned at
n o - f u e I with the governor stop le-
The exhaust valve bridge balance should
ver.
be checked when a general valve adjust-
ment is performed. After the bridges
are balanced, adjust the valve clearance
1. Adjust the exhaust valve clearance.
at the push rod only.
2. Time the fuel injectors.
D o not disturb the exhaust valve adjust-
i n g screw.
3. Adjust the governor gap.
All of the exhaust valves may be ad-
4. Position the injector rack control le-
justed in firing order sequence during
vers.
one full revolution of the crankshaft.
Refer to the General Specifications in
5. Adjust the maximum no-load speed.
Subsection 11A for the engine firing or-
der.
6. Adjust the idle speed.
VALVE CLEARANCE ADJUSTMENT
7. Adjust the buffer screw.
(COLD ENGINE)
8. Adjust the throttle booster spring.
1. Remove the loose dirt from the valve
rocker cover and remove the cover.
EXHAUST VALVE CLEARANCE AD-
2. Place the governor speed control lever
JUSTMENT
in the idle speed position. If a stop le-
ver is provided, secure it in the stop
position.
General
3. Rotate the crankshaft, manually or
The correct exhaust valve clearance at
with the starting motor, until the injec-
normal engine operating temperature is
tor follower is full depressed on the par-
important for smooth, efficient operation
ticular cylinder to be adjusted.
of the engine.
Insufficient valve clearance can result in
loss of compression, misfiring cylinders
and, eventually, burned valve seats and
I f a wrench is used on
the crank-
valve seat inserts. Excessive valve
shaft bolt at the front
of the en-
clearance will result in noisy operation,
gine, do not turn the
crankshaft
increased valve face wear and valve lock
i n a left-hand direction
of rotation
damage.
or the bolt may loosen.
Whenever the cylinder head is over-
hauled, the exhaust valves are recondi-
4. Loosen the exhaust valve rocker arm
tioned
or
replaced,
or
valve
push rod lock nut.
operating mechanism is replaced or dis-
turbed in any way, the valve clearance
5. Place a 0.017" feeler gage, J 9708-01,
must be first adjusted to the cold setting
between the end of the exhaust valve
to allow for normal expansion of the en-
