Unit Injector Tip Failure Caterpillar

THIS TIB REPLACES THE SEPTEMBER 09, 1998 ENGINE TIB, COMPONENT CODE 1290, "UNIT INJECTOR TIB BREAKAGE". DESTROY THE SEPTEMBER 09, 1998 TIB. IT WILL NOT APPEAR IN THE SEMI-ANNUAL INDEX.

Problem:

There have been several reports of unit injector tip breakage of these engines. This problem occurs at a very low failure rate. We are studying the affects of engine starting and cycling from low idle as contributors to the root cause. Any unique operating occurrences related to these failures may be reported to John Cox via E-mail at Cox_John_M@Cat.com.

Solution:

* Measure the torque of the Oil Deflector/Injector Hold Down Bolts (the "longer" bolts on the "left" or "lifter" side of the injectors) BEFORE disassembly. Use breakaway torque in "tightening" direction. Record results on Service Report.

* Inspect all six unit injector tips with a magnifying device for damage or cracks. Tip projection from the head surface should be 3.0 to 4.5 mm (.12 to .16 in). Replace the cylinder head if the tip projection is greater than 5.0 mm (.20 in).

* Inspect the turbocharger turbine wheel for damage. (Remove the turbocharger cartridge from the turbocharger for inspection because it is difficult to look through the outlet of the turbine wheel to see the inlet of the turbine blades.)

* Inspect the pistons and head for damage. The pistons may be reused if the damage is only minor. Replace the skirt if you have to replace the crown.

* Inspect the cylinder bores for damage. (Roll the piston to the bottom of the stroke.)

Send all broken and cracked injectors and replaced piston crowns and skirts, along with a completed Core Credit Request, and a copy of the Service Report to:

Please share this information with your TEPS Dealers.

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