TM 10-3950-206-12
4-55. Valve Adjustment
c. Remove three valve cover stud nuts with
gaskets. Remove valve cover and gasket.
d. Inspect valve springs, locks, spring seats, and
caps for distortion or improper placement. If defective
parts are found, report to proper authority.
e. Adjust intake valves, to 0.014 inch, and exhaust
valves to 0.017 inch clearance, with engine cold, per the
following 'instructions:
(1) Remove all spark plugs.
(2) Place thumb over No. 1 spark plug hole
and crank engine with starting motor a little at a time by
momentarily turning starter and ignition switch. When
No. 1 piston starts up on its compression stroke
pressure will be felt against thumb. When pressure is
felt, stop cranking engine with starting motor, remove
Figure 4-38. Checking cylinder head flatness crosswise.
thumb and continue cranking engine by hand while
observing timing pointer. When timing pointer and top
dead center mark is aligned, the No. 1 cylinder valves
are in position for adjusting.
(3) Slide feeler gage between the valve lifter
slight drag should be felt with the feeler gage when the
clearance is correct.
(4) To increase clearance, hold valve lifter with
an open end wrench while using a second to turn
adjusting screw one-quarter to one-half turn clockwise.
Repeat clearance check and adjustment until proper
Figure 4-39. Cylinder head bolt tightening sequence.
clearance is obtained. The adjustable-type valve lifters
have self-locking adjusting screws that require no
locknuts.
(5) To decrease clearance, hold valve lifter
control valve piping from intake manifold.
with an open end wrench while using a second wrench to
turn valve lifter adjusting screw counterclockwise one-
(5 and 13). Remove manifold assembly from block.
quarter to one-half turn. Repeat clearance check and
(5) Separate intake manifold (1) and exhaust
adjustment until proper clearance is obtained.
manifold (8) by removing four nuts (10) and washers (9).
(6) Following firing order, turn crankshaft one-
Remove gaskets (7 and 11).
half revolution and adjust valves for No. 5 cylinder. Turn
b. Cleaning and Inspection.
crankshaft one-half revolution and adjust valves for No.
(1) Clean dirt from manifold with a wire brush;
3 cylinder. Turn crankshaft one-half revolution and
then clean with a cloth dampened in an approved
adjust valves for No. 6 cylinder. Turn crankshaft one-
cleaning solvent.
half revolution and adjust valves for No. 2 cylinder. Turn
(2) Inspect manifold for cracks, warping,
crankshaft one half revolution and adjust valves for No.
damaged sealing surfaces, corroded areas, damaged
4 cylinder.
threads, or other defects.
f. Install valve cover with a new gasket and secure
(3) Inspect for loose or damaged studs.
with three valve cover stud nuts with gaskets.
(4) Replace gaskets; replace other parts if
defective.
c. Installation. Reverse procedures in a above.
4-43