Removal. - TM-5-6115-440-340045

reseat in a different position to insure uniform

b. Removal.

seating. After valves are properly lapped, remove

(1) Remove the cylinder block (para 3-24).

them from cylinder block and wash valves and

(2) Refer to figure 3-28 and remove the engine

block thoroughly in an approved cleaning solvent

valves.

( F E D - P D - 6 8 0 ) . Tag each lapped valve with its

(3) Remove valve guides and seats as shown

mated valve guide for proper assembly.

by step 1 and 2 figure 3-29.

(4) Inspect the valve springs (9) for damage

c. Disassembly. Refer to figure 3-30 and

and test for spring tension as follows:

disassemble the valves and attaching parts.

(a) Test tension of spring with a suitable

d. Cleaning.

spring tension tester.

(1) Clean the valve guide parts in the cylinder

(b) Compress each spring to 1.271 inches

blocks and blow out with compressed air.

and note reading on the tester. If reading is less

(2) Clean the valve seat insert recesses and the

than 51 pounds, replace spring.

top of cylinder block.

f. Reassembly. R e f e r t o f i g u r e 3 - 3 0 a n d

e. Inspection and Repair.

reassemble the valves and attaching parts in reverse

(1) Inspect the valves (7, fig. 3-30) and seats

procedure of removal.

for burned, pitted, or cracked faces.

CAUTION

(2) The cylinder blocks have replaceable valve

guides. The valve stems should have a clearance of

Make certain valve spring seat locks (6)

0.0025 to 0.0045 inch in the guides. Replace valve

are

properly

seated

before

releasing

guides that exceed 0.008 inch clearance.

s p r i n g tension.

g. Installation.

( 3 ) Grind serviceable valves (7) and seat

inserts (10) to an angle of 45 degrees to the vertical

(1) Install valve guides and seats as shown in

steps 3, 4, and 5 figure 3-29.

center lines. After grinding, lap the valve and valve

(2) Refer to figure 3-28 and install the valves

seat insert with suitable lapping compound, to

in reverse procedure of removal.

provide proper fit. C l e a n the valve and apply

lapping compound to the valve face. Insert the

(3) Install the cylinder block (para 3-24).

h. Adjustment. Adjust the valve tappets (TM 5-

valve in their valve guide (11) and lap by rotating

t h e valve back and forth with a reciprocating

advancing valve tool. Occasionally lift the valve

3-33