Usage:
3208 Truck Engines (2Z, 51Z)
Description of Change: The valve in the fuel injection pump bonnet on 3208 Truck Engines has been changed from an orifice delivery valve (ODV) to an orifice reverse flow check valve (ORFC). See illustration.
Comparison of the fuel Injection valves.
The new valves prevent compression gases from entering the nozzle and fuel lines if the nozzle sticks open due to debris. In most situations, this will allow the next injection stroke(s) to clear the debris from the nozzle.
The former valves would not prevent gases from entering the nozzle or fuel lines if the nozzle stuck open due to debris, and the debris could not be cleared out by more injection strokes.
Adaptable To: The new 1W6987 Valve Assembly (ORFC) is effective with the 3208 Truck Engines listed in the chart. It can be used as a direct replacement for the former 4W5869 Valve (ODV) on the listed engines. These engines have the Cat 7000 Series Nozzles, and are also identified by notches on the sides of the external fuel line nuts. The former valve is canceled. Change valves only in complete sets.
The new valves can be used in engines where either "engine misfire" for "cold cylinders" is a problem.