SHAFT 1212511 - Caterpillar

3500 Family Of Engines With Type 2 Injectors (11 mm)Reference: Service Magazine; January 19, 1987; Page 6; "Fuel Injector Reference For 3500 Family Engines".Reference: Special Instruction SEHS8993, "Nozzle Assembly Replacement For Type 2 Injectors".Replacement nozzle assemblies are available for all Type 2 unit injectors in the 3500 Family Of Engines. See chart.
The reference article lists the effective serial numbers of engines using Type 2 injectors, and shows how to identify a Type 2 injector from the earlier Type 1 injector. See following illustration.
Most type 2 injectors have the two-piece follower shown, but later ones have the one-piece follower. The part number of the Type 2 injector group did not change. The group part number is on the side of the injector body.Shortly after the replacement nozzles became available, the nose cone around the nozzle on Type 2 injectors was improved for service reasons. The new 7C9795 Nose Cone has a hexagonal outside shape, whereas the former 4W3566 Nose Cone has serrations. Do not reuse the former cone. Remove the former cone and discard it. Replace all serrated cones with the hexagonal cones.
To facilitate the removal and installation of the new cone when the nozzle is replaced, the following new tools are now available.
1U8701 Socket6V4822 Tip Driver6V4830 Fixture Gp.1U9395 PlateThe referenced Special Instruction shows how to use the new tooling to install and remove the new hexagonal nose cones. The injector must be properly held in the fixture and the correct torque used to tighten the nose cone.