Needle Valve Lift Test.

TM 9-2815-224-34&P

Fuel Injectior Maintenance Instructions (Cont)

(35) Dry injector parts with compressed air.

(36) Apply lapping and grinding compound to second lapping block.

(37) Move dry injector part flat on lapping block lightly in a figure-eight motion. Lap part until finish

is smooth.

Clean injectr parts in dry cleaning solvent and dry with compressed air.

(38)

(39)

Place dry injector part on third lapping block, using no lapping and grinding compound.

(40)

Keep injector part flat and move it across third block several times in a figure-eight motion.

Clean all lapped injector parts in diesel fuel oil and dry with compressed air.

(41)

c. Needle Valve Lift Test.

(1) Adjust spray tip gage to zero.

(2) Install spray tip (1) and needle

valve (2) assembly on gage with

needle valve quill (3) in plunger of

gage.

NOTE

Needle valve lift limits are 0.008 to

0.018-in. (0.203 to 0.457 mm).

(3) If valve lift is above limits, replace

spray tip and needle valve

assembly (4). If valve lift is below

limits, inspect for contamination and clean needle valve assembly (4).

d. Needle Valve Tip Test.

(1) Install tip test adapter (1) in vise

and install check valve cage (2),

spring (3), spring seat (4), spring

cage (5), needle valve (6), and

spray tip (7).

(2) Install injector valve nut (8) over

spray tip assembly (7) onto tip

test adapter (l).

(3) Tighten injector valve nut (8) to

75 to 85 lb-ft (102 to 115 N-m).

(4) Remove tip test adapter (1) and

assembled parts from vise.

12-13