Figure 5-17. Valve System (Model RMP-J/1-lOG)

TM 5-4110-217-14

e. Remove all grinding compound from engine

e. Remove valves (177) & (178) from crankcase.

f. Remove valve springs (172) & rotators (170) &

parts and place each valve in its proper location.

(171).

Check each valve for a tight seat using an air

g. Worn valve stem guides (174) may be replaced

pressure type testing tool If such a tool is not available,

from inside the valve chamber. A O-ring seal (173) is

make pencil marks at intervals across the valve face and

provided behind the intake valve guides (174) only.

observe if the marks rub off uniformly when the valve is

h. Tappets (168) are also replaceable from the

rotated part of a turn against the seat.

valve chamber, after first removing the valve assemblies.

f Lightly oil the valve stems prior to installation.

5-19. Cleaning and Inspection.

a. Clean all carbon and gum deposits from the

valve, valve rotators, seats, ports, and guides in the

cylinder block with an approved cleaning solvent.

b. Inspect valve springs for set or out-of-round.

Inspect valve rotators and spring washer locks for

damage or wear Replace unrepairable or defective parts.

c. The valve face angle is 44 degrees. The valve

seat angle is 45 degrees. This 1-degree interference

angle results in a sharp seating surface between the

valve and the top of the valve seat. The interference

angle method of grinding valves minimizes face deposits

and lengthens valve life (fig. 5-18).

d. The valves should not be hand lapped, if at all

avoidable, since the sharp contact may be destroyed.

This is especially important where stellite faced valves

and seats are used. Valve faces should be finished in a

machine to 44 degrees. Valve seats should be ground

with a 45 degree stone and the width of the seat band

should be 1/32 to 3-64 of an inch wide. Grind only

enough to assure proper seating.

Figure 5-18. Valve Face and Seat Angles (Model RMP-

J/1-IOG)

5-11