TM 5-3810-295-34
Figure 4-4. Water nozzle installation
b Position the cylinder head right side up on wooden blocks. Position valve guides (48) squarely in the bore in the
cylinder head. Gently press the guides in until the top of the guide is 0.010 to 0.040 inch below the top of the head.
c. Immerse the cylinder head in water heated to 180' to 200F. for at least 30 minutes. With the head resting bottom
side up on a bench, quickly place the valve seat inserts (47) into the counterbores in the cylinder head face. Drive the
inserts in place until they are firmly seated in the head.
d If an old insert is to be refaced, or if a new insert is installed, the work must be done with a grinding wheel, using the
eccentric grinding method. Use the following procedure:
(1) Apply a 30 grinding wheel on the valve insert.
(2) Use a 60 grinding wheel to open the throat of the insert.
(3) Grind the top surface with a 15 wheel to narrow the width of the seat from three sixty-fourth to five sixty-fourths
of an inch. (Refer to fig. 4-3.)
CAUTION
Do not allow the grinding wheel to contact the cylinder head while grinding the insert. If necessary, replace the
insert.
(4) Check the concentricity of each valve seat insert relative to the valve guide with a dial indicator. If runout
exceeds 0.002 inch, check for a bent valve guide before regrinding the insert.
(5) Apply a light coat of Prussian Blue to the valve seat insert. Lower the stem of the valve in the valve guide and
bounce the valve on the seat. Do not rotate the valve. This procedure will show the area of contact on the valve face. The
most desirable area of contact is at the center of the valve face.
e Before installing valves (46), check to see that the valves are within specifications shown in figure 4-3. Lubricate the
valve stems with engine oil and slide the valves all the way into the guides.
NOTE
If reconditioned valves are used, be sure they are installed in the same relative locations from which they were removed.
f
Hold the valves in place temporarily with a strip of masking tape. Turn the head right side up on the work bench, and
place a board beneath the head to support the valves. Install valve springs (44), seats (45) and caps (43).
g Compress the valve springs and install valve locks (42). Check the position of the valve against the specifications
shown in figure 4-3. Using a spring checking gage, note the gage reading at which the exhaust valve begins to open. The
minimum pressure required to start the valve to open must not be less than 25 pounds (34 N. m).
h Assemble cam follower roller (52) and cam follower (53). The cam follower roller must roll smoothly and freely on its
pin, and the roller must be free from fiat spots and scuff marks. Check roller clearances as shown in figure 4-5.
4-5
