Cylinder Head - TM-10-3930-627-120051

TM 10-3930-627-12

4-15. Test

Use all test and diagnostic equipment available to

organizational maintenance to detect actual or potential

troubles. Perform all tests as instructed by the maker of

the test equipment used.

4-16. Cylinder Head

The cylinder head contains the fuel combustion

chambers and the cored passages for water flow. Refer

to figure 4-1 and remove the cylinder head as follows:

a. Removal.

(1) Drain cooling system.

(2) Remove bolts and lockwashers and

remove coil mounting support (5, fig. 4-1) with coil from

Figure 4-2. Cylinder head tightening order.

side of cylinder head. Capacitor is removed in this

4-17. Valves and Valve Cover

procedure.

a. Removal of Cover.

(3) Remove distributor from cylinder head

(1) Remove air cleaner (para 4-24).

(para 4-35).

(2) Remove carburetor (para 4-22).

(4) Disconnect wire at engine temperature

(3) Remove fuel pump (para 4-26).

transmitter (4).

(4) Remove two valve cover mounting

(5) Remove water pump to thermostat

screws (8, fig. 4-5) with gaskets and remove cover and

elbow (housing) recirculating tube (1).

gasket from engine.

(6) Loosen hose clamp and disconnect

b. Inspection. Inspect valve springs, locks,

elbow to radiator hose (3) at elbow.

seats, (retainers) and caps as follows. If defective parts

(7) Remove lifting eyes (2) from cylinder

are found, report to proper authority.

head studs.

(1) Inspect springs for breaks, cracks,

(8) Remove cylinder head stud nuts and

fatigue, and proper seating on the seats (retainers) and

flat washers and remove cylinder head (6) and gasket

engine block.

from engine block.

(2) Inspect seats (retainers) and locks for

(9) Remove stud nuts and lockwashers

placement, breaks, and cracks.

and remove elbow (housing) and thermostat from

c. Valve Adjustment (fig. 4-3).To position No. 1

cylinder head.

cylinder valves for adjustment, proceed as follows:

(10)

Remove engine temperature

(1) Remove spark plugs.

transmitter from the cylinder head.

(2) Place thumb over No. 1 spark plug

(11) Remove spark plugs.

hole and crank engine with starting motor a little at a time

b. Cleaning and Inspection.

by momentarily pushing starter button. When the No. 1

(1) Remove all carbon from combustion

position starts up on its compression stroke, pressure

areas, using a scraper and wire brushes.

will be felt against the thumb. When pressure is felt,

(2) Clean the cylinder head thoroughly with

stop cranking engine with starting motor, remove thumb

SD.

and continue cranking engine by hand while observing

(3) Make sure that gasket contact surfaces

timing pointer. When timing pointer and top dead center

on the head and block are clean, smooth, and flat.

mark are aligned, the No. 1 cylinder valves are in

(4) Inspect the head for cracks and holes.

position for adjusting.

Check flatness with straightedge and feeler gage in three

(3) Slide a 0.014-inch feeler gage between

positions lengthwise and five crosswise. The maximum

the valve lifter adjusting screw and the valve stem cap. A

permissible is 0.004 inch low in the center lengthwise,

slight drag should be felt with the feeler gage when the

gradually decreasing towards the ends, or 0.003 inch

clearance is correct.

crosswise or in localized low spots.

(4) To increase clearance, hold valve lifters

c. Installation.

with a 9/16-inch tappet wrench and turn the adjusting

(1) Reverse procedures in a above using a

screw clockwise with a '/2-inch tappet wrench.

new gasket.

(5) To decrease clearance, hold the valve

(2) Tighten each cylinder head nut to 70 to

lifter and turn the adjusting screw counterclockwise.

75 foot-pounds torque, following the sequence in figure

4-2.

4-6