DETROIT DIESEL 53
Fuel Injector 2.1.1
Install the injector in the engine as follows:
Check Spray Tip -Concentricity
1. Refer to Fig. 6. and insert the injector into the
To assure correct alignment, check the concentricity of
injector tube with the dowel pin in the injector body
the spray tip as follows:
registering with the locating hole in the cylinder head.
1. Place the injector in the concentricity gage J 5119
2. Slide the injector rack control lever over so that it
as shown in Fig. 42. and adjust the dial indicator to
registers with the injector rack.
zero.
3. Install the injector clamp, special washer (with
2. Rotate the injector 360' and note the total run-out as
curved side toward injector clamp) and bolt. Tighten the
indicated on the dial.
bolt to 20-25 lb-ft torque. Make sure that the clamp
does not interfere with the injector follower spring or the
3. If the total run-out exceeds .008", remove the
exhaust valve springs.
injector from the gage. Loosen the injector nut,)center
the spray tip and tighten the nut to 75-85 lb-ft torque.
NOTE: Check the injector control
Recheck the spray tip concentricity. If, after several
attempts, the spray tip cannot be positioned
rack for free movement.
Excess
satisfactorily, replace the injector nut.
torque can cause the control rack to
stick or bind.
Test Reconditioned Injector
4. Move the rocker arm assembly into position and
Before placing a reconditioned injector in service,
secure the rocker arm bracket to the cylinder head by
perform all of the tests (except the visual inspection of
tightening the bolts to 50-55 Ib-ft torque.
the plunger) previously outlined under Test Injector.
CAUTION: There is a possibility of
The injector is satisfactory if it passes these tests.
damaging the exhaust valves if the
Failure to pass any one of the tests indicates that
exhaust valve bridge is not resting
defective or dirty parts have been assembled. In this
on the ends of the exhaust valves
case, disassemble, clean, Inspect, reassemble and test
when tightening the rocker shaft
the injector again.
bracket bolts. Therefore, note the
position of the exhaust valve bridge
Install Injector
(Fig. 43.) before, during and after
tightening the rocker shaft bolts.
Before installing an injector in an engine, remove the
carbon deposits from the beveled seat of the injector
5. Remove the shipping caps. Then install the fuel
tube in the cylinder head The, will assure correct
pipes and connect them to the injector and the fuel
alignment of the injector and prevent any undue
connectors. Use socket J 8932-01 to tighten the
stresses from being exerted against the spray tip.
connections to 12-15 lb-ft torque.
Use injector tube bevel retainer J 5286-9, Section 2.1.4,
CAUTION: Do not bend the fuel
to clean the carbon from the injector tube. Exercise
pipes and do not exceed the
care to remove ONLY the carbon so that the proper
specified
torque.
Excessive
clearance between the injector body and the cylinder
tightening will twist or fracture the
head is maintained. Pack the flutes of the reamer with
flared end or the fuel line and result
grease to retain the carbon removed from the tube.
in leaks. Lubricating oil diluted by
fuel oil can cause serious damage to
Be sure the fuel injector is filled with fuel oil. If
the engine bearings.
necessary, add clean fuel oil at the inlet filter cap until it
runs out of the outlet filter cap.
6. Perform a complete engine tune-up as outlined in
Section 14. However, if only one injector has been
removed and replaced and the other injectors and the
governor adjustment have not been disturbed, it will only
be necessary to adjust the valve clearance and time the
injector for the one cylinder, and to position the injector
rack control lever.
1972 General Motors Corp.
July, 1972
SEC. 2.1.1 Page 21
