CAMSHAFT GP 2168620 - Caterpillar

Injection 3406, 3408 And 3412 Engines In All ApplicationsDescription of Change: The internal clearances have been increased in the 9L6884 Fuel Injection Nozzle Assemblies used in direct injection 3406, 3408 and 3412 Engines. Because of increased clearances, some test procedures and specifications for the 9L6884 Fuel Injection Nozzle Assemblies must be changed.
Make the changes which follow in, "Use Of 5P4150 Nozzle Testing Group And 8S2245 Nozzle Cleaning Kit," Special Instruction Form No. SEHS7292-02.
In the "Pressure Loss Specification" at the top of page 11, change the specification to: "Nozzle must have a loss of at least 200 psi (1379 kPa) in 30 seconds. A rapid loss of pressure, even to zero, is acceptable."
In the "Tip Leakage Test" on page 12, add to Step A:
"Wrap a clean shop towel around the lower part of the adapter. This prevents return leakage down the outside of the adapter which gives a false tip leakage indication."
Change Step B to: "Increase pressure to between 500 psi (3450 kPa) and 1000 psi (6875 kPa). Hold this pressure for 30 seconds." Also make the changes to the charts, Special Instruction, Form Numbers SEHS7311 and SEHS7350.
None of the other tests and specifications have been changed.
The new procedures and specifications also are good for the earlier 9L6884 Fuel Injection Nozzle Assemblies which have the smaller clearances.