DETROIT DIESEL 53
Fuel Injector 2.1.1
Inspect both ends of the spill deflector for sharp edges or burrs which could create burrs on the injector body or injector
nut and cause particles of metal to be introduced into the spray tip and valve parts. Remove burrs with a 500 grit stone.
Inspect the follower spring for visual defects. Then check the spring with spring tester J 9666 and an accurate torque
The current injector follower spring (.142 " diameter wire) has a free length of approximately 1.504 " and should be
replaced when a load of less than 70 lbs. will compress it to 1.028 ".
It is recommended that at the time of overhaul, all injectors in an engine be converted to the current spring (.142 "
diameter wire) which will provide improved cam roller to shaft follow. However, in the event that one or two injectors are
changed, the remaining injectors need not be reworked to incorporate the current spring.
Check the seal ring area on the injector body for burrs or scratches. Also check the surface which contacts the injector
bushing for scratches, scuff marks or other damage. If necessary, lap this surface. A faulty sealing surface at this point
will result in high fuel consumption and contamination of the lubricating oil. Replace any loose injector body plugs or a
loose dowel pin. Install the proper number tag on a service replacement injector body.
Inspect the injector plunger and bushing for scoring, erosion, chipping or wear. Check for sharp edges on that portion of
the plunger which rides in the gear. Remove any sharp edges with a 500 grit stone. Wash the plunger after stoning it.
Injector Bushing Inspectalite J 21471 can be used to check the port holes in the inner diameter of the bushing for cracks
or chipping. Slip the plunger into the bushing and
Fig. 35. Details of Injector Filters and
Caps and Their Relative Location
Fig. 36. Injector Rack, Gear, Spray Tip and Valve
Assembly Details and Relative Location of Parts