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TM 5-4320-308-13
5-2.
REPAIR CYLINDER HEAD AND VALVE ASSEMBLY (Continued)
5
The cylinder contact surface of the cylinder head can be repaired by machining. Remove up to a maximum of 0.
0196 inch (0.5 mm) of metal provided the minimum valve recession is maintained.
6
Replace any valves that show head warping, burning, or other damage.
7
Replace valves that have seriously scratched or scuffed stems, or pitted, ridged, or cracked tulips faces, or
heads.
8
Replace valves that have a valve head diameter of less than 1.200 inch (30.5 mm).
9
Remove slight scratches or scuff marks.
10
If the cylinder head valve seats were recut, lap the valves by using tool 604 581 00 and 600 grit lapping and
grinding compound.
11 After lapping valves check valve recession.
CAUTION
The valve recession must not be less than 0. 018 inch (0. 45 mm), otherwise valve
head may touch piston.
The valve recession shall be a maximum of 0. 0275 inch (0. 70 mm) and a minimum of 0. 0180 inch
(0.45 mm).
TEST:
1
Insert valve (1) into cylinder head (2).
2
Install cap (3) over valve (1) stem.
3
Install washer (4) on cap (3).
4
Install spring (5) on washer (4).
5
Insert cup (6) into spring (5).
6
Install two collets (7) into cup (6) and over valve
(1) stem.
7
Press down on collets (7) and cup (6) until
spring (5) compresses and collets (7) are locked
in slot in valve (1) stem.
5-4
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