DETROIT DIESEL 53
Injector Tube 2.1.4
Fig. 5 - Reaming Injector Tube for Injector Nut
Fig. 6 - Checking Location of Injector Spray
Tip Relative to Lower Surface of Cylinder Head
3. Ream the bevel seat in the injector tube: The tapered lower end of the injector tube must provide a smooth
and true seat for the lower end of the injector nut to effectively seal the cylinder pressures and properly
position the injector tip in the combustion chamber. Therefore, to determine the amount of stock that must
be reamed from the bevel seat of the tube, the injector assembly should be installed in the tube and the
relationship between the numbered surface of the spray tip to the fire deck of the cylinder head noted ( Fig.
With the first reaming operation completed and the injector tube spot-faced, wash the interior of the injector
tube with trichloroethylene or clean fuel oil and dry it with compressed air. Then perform the second
reaming operation as follows:
a. Place a few drops of cutting oil on the bevel seat of the tube. Carefully lower the reamer J 5286-9 into the
injector tube until it contacts the bevel seat.
b. Make a trial cut by turning the reamer steadily without applying any downward force on the reamer.
Remove the reamer, blow out the chips and look at the bevel seat to see what portion of the seat has been
Proceed carefully with the reaming operation, withdrawing the reamer occasionally to observe the reaming
d. Remove the chips from the injector tube and, using an injector as a gage, continue the reaming operation
until the shoulder of the spray tip is within the limits specified in Fig. 6. Then wash the interior of the
injector tube with trichloroethylene or clean fuel oil and dry it with compressed air.
November, 1973 SEC. 2.1.4