DETROIT DIESEL 53
Fuel lnjector 2.1.1
The exterior surface of an injector spray tip may he
cleaned by using a brass wire buffing wheel, tool
J 7944. To obtain a good polishing effect and longer
brush life, the buffing wheel should be installed on a
motor that turns the wheel at approximately 3000 rpm.
A convenient method of holding the spray tip while
cleaning and polishing is to place the tip over the drill
end of the spray tip cleaner tool J 1243 and hold the
body of the tip against the buffing wheel. In this way,
the spray tip is rotated while being buffed.
CAUTION: Do not buff excessively. Do not use a
steel wire buffing wheel or the spray tip holes may
be distorted.
When the body of the spray tip is clean, lightly buff
the tip end in the same manner. This cleans the spray
Fig. 34 - Location of Filter In lnjector Body
tip orifice area and will not plug the orifices.
Carefully insert carbon remover tool J 9418-1 in the
Wash the spray tip in clean fuel oil and dry it with
injector nut. Turn it in a clockwise direction to remove
compressed air.
the carbon deposits on the flat spray tip seat as shown
in Fig. 30. Remove the carbon deposits from the lower
Clean and brush all of the passages in the injector
end of the injector nut with carbon remover J 9418-5
body, using fuel hole cleaning brush J 8152 and rack
(Fig. 30) in the same manner. Use care to prevent
hole cleaning brush J 8150. Blow out the passages and
removing any metal or setting up burrs on the spray
dry them with compressed air.
tip seat.
Carefully insert reamer J 21089 in the injector body
Wash the injector nut in clean fuel oil and dry it with
(Fig. 29). Turn it in a clockwise direction a few turns,
compressed air. Carbon deposits on the spray tip
then remove the reamer and check the face of the ring
seating surfaces of the injector nut will result in poor
for reamer contact over the entire face of the ring. If
sealing and consequent fuel leakage around the spray
necessary, repeat the reaming procedure until the
tip.
reamer does make contact with the entire face of the
ring. Clean up the opposite side of the ring in the
When handling the injector plunger, do not touch the
same manner.
finished plunger surfaces with your fingers. Wash the
plunger and bushing with clean fuel oil and dry them
Carefully insert a .375 " diameter straight fluted
with compressed air. Be sure the high pressure bleed
reamer inside the ring bore in the injector body. Turn
hole in the side of the bushing is not plugged. If this
the reamer in a clockwise direction and remove any
hole is plugged, fuel leakage will occur at the upper
burrs inside the ring bore. Then wash the injector
end of the bushing where it will drain out of the
body in clean fuel oil and dry it with compressed air.
injector body vent and rack holes, during engine
operation, causing a serious oil dilution problem. Keep
the plunger and bushing together as they are mated
parts.
After washing, submerge the parts in a clean
receptable containing clean fuel oil. Keep the parts of
each injector assembly together.
Inspect Injector Parts
Inspect the teeth on the control rack and the control
rack gear for excessive wear or damage. Also check for
excessive wear in the bore of the gear and inspect the
gear retainer. Replace damaged or worn parts.
Fig. 33 - Lapping Spray Tip on Lapping Blocks
Inspect the injector follower and pin for wear. Refer to
J 22090
Section 2.0.
SEC. 2.1.1 Page 15
March, 1973
