TM 5-3810-300-24&P-3
Fuel Injector 2.1.1
2. Invert the injector in the assembly fixture (filter cap end up)
1. Support the injector body, bottom end up, in injector holding
and push the rack all the way in. Then place the follower
fixture J 22396.
spring on the injector body.
2. Place a new seal ring on the shoulder of the body. Then
3. Refer to Fig. 41 and place the stop pin on the injector body
place the spill deflector over the barrel of the bushing.
so that the follower spring rests on the narrow flange of the
stop pin. Then align the slot in the follower with the stop pin
3. Place the check valve (without the .010"hole) centrally on
hole in the injector body. Next align the flat side of the plunger
the top of the bushing. Then place the check valve cage over
with the slot in the follower. Then insert the free end of the
the check valve and against the bushing.
plunger in the injector body. Press down on the follower and
at the same time press the stop pin into position. When in
CAUTION: The former and new check valve
place, the spring will hold the stop pin in position.
and check valve cage are not separately
interchangeable in a former injector (Fig,.
Check Spray Tip Concentricity
38).
To assure correct alignment, check the concentricity of the
4. Insert the spring seat in the valve spring, then insert the
spray tip as follows:
assembly into the spring cage, spring seat first.
1. Place the injector in the concentricity gage J 5119 as
CAUTION: Install a new spring seat (Fig.
shown in Fig. 42 and adjust the dial indicator to zero.
38) in a former injector if a new design spray
tip assembly is used.
2. Rotate the injector 360 and note the total runout as
indicated on the dial.
5. Place the spring cage, spring seat and valve spring
assembly (valve spring down) on top of the check valve cage.
3. If the total runout exceeds .008", remove the injector from
the gage. Loosen the injector nut, center the spray tip and
CAUTION: When installing a new spray tip
tighten the nut to 75-85 lb-ft (102115 Nm) torque. Recheck
assembly in a former injector, a new valve
the spray tip concentricity. If, after several attempts, the spray
spring seat must also be installed. The
tip cannot be positioned satisfactorily, replace the injector nut.
current needle valve has a shorter quill.
Test Reconditioned Injector
6. Insert the needle valve, tapered end down, inside of the
spray tip (Fig. 2). Then place the spray tip and needle valve
Before placing a reconditioned injector in service, perform all
on top of the spring cage with the quill end of the needle valve
of the tests (except the visual inspection of the plunger)
in the hole in the spring cage.
previously outlined under Test Injector.
7. Lubricate the threads in the injector nut and carefully thread
The injector is satisfactory if it passes these tests. Failure to
the nut on the injector body by hand. Rotate the spray tip
pass any one of the tests indicates that defective or dirty parts
between your thumb and first finger while threading the nut on
have been assembled. In this case, disassemble, clean,
the injector body (Fig. 39). Tighten the nut as tight as
inspect, reassemble and test the injector again.
possible by hand. At this point there should be sufficient force
on the spray tip to make it impossible to turn with your fingers.
install Injector
8. Use socket J 4983-41 and a torque wrench to tighten the
Before installing an injector in an engine, remove the carbon
injector nut to 75-85 lb-ft (102-115 Nm) torque (Fig. 40).
deposits from the beveled seat of the injector tube in the
cylinder head. This will assure correct alignment of the
NOTE: Do not exceed the specified torque.
injector and prevent any undue stresses from being exerted
Otherwise, the nut may be stretched and
against the spray tip.
result in improper sealing of the lapped
surfaces in a subsequent injector overhaul.
Use injector tube bevel reamer J 5286-9, Section 2.1.4, to
clean the carbon from the injector tube. Exercise care to
Assemble Plunger and Follower
remove ONLY the carbon so that the proper clearance
between the injector body
1. Refer to Fig. 37 and slide the head of the plunger into the
follower.
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