center on its compression stroke at the time of
adjustment of valves for that cylinder. To determine the
correct position, turn the engine crankshaft until No. 1
piston is at top dead-center on the compression stroke
and the ignition timing mark on the flange of the fan drive
pulley is in line with the pointer on the crankcase front
h. Loosen the adjusting screw lock nut on both the
Figure 4-2. Crane engine head bolt tightening
clearance to 0.002 inch more than the hot clearance
shown in table 1-4. Tighten the lock nut and recheck.
e. Assemble rocker arm assembly, spring (44, fig. 4-
i. Crank the engine one-third revolution at a time and
1), expansion plugs (45), brackets (43) bushings (42),
set the clearance of the valve for each cylinder. Do this
couplings (47), rocker arm (41) spring (38), washers
on each set of cylinder valves in succession according to
(37), and retainers (36). Install adjusting screws (40)
the firing order of the engine. The firing order is 1, 5, 3,
and nuts (39) on rocker arm.
6, 2, 4.
f. Install bolts (5), nuts (6), and washers (7 and 8).
j. Recheck the valve clearance with the engine at
Install oil bolt washer (15), gasket (10) and oil bolt (9).
normal operating temperature and make final
Tighten all bolts to a torque of 25 foot-pounds, except oil
adjustments if necessary, from the cold adjustment just
bolt (9) to 65 foot-pounds.
performed. Place gasket (4), cover (3) and secure with
g. To adjust the valve stem to valve rocker arm
clearance, each piston must be on the top dead-
Section III. REPAIR OF GEAR COVER
The gear cover provides access to the gear train,
which provide a positive and accurate drive for the
oil pump, governor, and distributor. The gears
must be properly alined for accurate timing.
Starting nut washer
Lock tab (2)
Oil seal (2)
Engine front support
Oil seal (2)
Engine support insulator
Throttle lever shaft