Figure 4-64. Valve chamber cover, removal and installation

TM 10-3930-630-12

4-83.

Engine Valves

(4) Tighten screws in successive stages to

ensure equal pressure over entire surface of cylinder

a. General The intake and exhaust valves are

head and gasket. Hold tension on each screw for a few

seconds before releasing torque wrench.

mounted in the engine block and are operated by the

(5) At first pass apply approximately one-half

camshaft.

b. Adjustment. The valve tappet clearance may

of the recommended torque and then increase the

torque one-half each pass until recommended torque is

require adjustment.

obtained. Torque all screws to 70 to 75 pound-feet

(1) Open left side panel

(94.9 to 101.5 N-m).

(2) Refer to paragraph 4-57 and remove the

(6) Refer to paragraph 4-50 and install cooling

air cleaner.

temperature sending unit in cylinder head.

(3) Refer to paragraph 4-58 and remove

(7) Refer to paragraph 4-70 and install engine

carburetor and governor and associated linkage.

coolant outlet elbow and thermostat and connect coolant

(4) Refer to paragraph 4-50 and remove oil

bypass hose to cylinder head.

pressure and hourmeter actuator sending units.

(8) Refer to paragraphs 4-53 and 4-54 and

(5) Disconnect crankcase ventilation hose

instal spark plugs and distributor in cylinder head.

from valve chamber cover and remove valve chamber

(9) Close side panels and lower seat into

cover (fig. 4-64) and gasket from left side of engine

position.

beneath manifold.

Figure 4-64. Valve chamber cover, removal and installation

(6) Disconnect high tension wire from top of

(10) When timing pointer is in this position both

distributor. Clean area around spark plug and remove

valves on number one cylinder are closed on

spark plug from number one cylinder (spark plug closest

compression stroke

to coolant outlet elbow).

(11) Check valve tappet clearance with a feeler

(7) Refer to timing marks on flywheel or flex

gage as shown on figure 4-65.

plate.

(12) Clearance should be 0.012 inch (0.304

(a) To gain access to flex plate timing

mm) for intake valves and 0.020 inch (0.508 mm) for

exhaust valves.

marks (fig. 4-43) remove battery and battery box (para

(13) If clearances are not as specified use two

4-46). Remove access from flywheel housing.

(b) Timing marks (fig. 443) at fuel pump

thin wrenches as shown in figure 4-66 to adjust valve

tappet clearance. Loosen the lock nut. Use the lower

location are accessible through hole in flywheel housing.

wrench to hold the tappet and the upper wrench to raise

(8) Place a thumb over the spark plug opening

or lower tappet adjusting screw.

and slowly crank engine until outward pressure can be

(14) Continue to raise or lower adjusting screw

felt against thumb. This pressure indicates number one

and checking with feeler gage until proper clearance is

piston is moving toward Top Dead Center of the

obtained.

compression stroke.

(15) Tighten lock nut when correct clearance is

(9) Continue cranking until timing pointer

obtained. Check clearance after tightening.

(fig.4-43) is in line with Dead Center mark on flywheel.

4-74