Usage:
3606 (8RB1),
3608 (6MC1),
3612 (9RC1),
3616 (1PD1) Engines
Reference: Service Magazine; May 15, 1989; Page 7; "New Installation Procedure For Unit Injectors".
Unit injector tips now have an improved brazing technique to reduce the possibility of leakage into the injector fuel cooling passage. Previously, the brazed tip had a tendency to make a poor bond which resulted in leakage and potential carbon build-up in the cooling passage.
An injector with a poorly brazed tip can be located by removing a plug and inspecting the plug and fuel cooling passage of the cylinder head (see illustration). If either the plug or cooling passage contains carbon deposits, there may be a defective braze on that unit injector.
Engine performance is not effected, but carbon build-up may make the injector difficult to remove for service in the future. The improved unit injectors have a supplier serial number of GF101 or higher.
Location of plug to be removed to inspect for carbon deposits.