Cummins 3079946 Fuel Injector Assembly

The Cummins 3079946 is a PT (Pressure-Time) mechanical fuel injector assembly designed for the Cummins NT855 series heavy-duty diesel engines. It utilizes a mechanical actuation mechanism driven by the engine camshaft via push tubes and rocker levers to meter and inject fuel into the combustion chamber. The injector body is constructed from high-speed steel and alloy steel to withstand high cyclic pressures and abrasive wear. It features a multi-hole nozzle tip calibrated for specific fuel spray patterns required by the NT855, NTA855, NH855, and N14 Mechanical engine configurations. This part number supersedes and interchanges with assembly numbers 3079947, 3081277, 3087587, and 3087648. It is a critical component in the PT fuel system, requiring clean fuel supply and precise adjustment of injector plunger travel (lash) during installation to ensure optimal engine performance, emissions compliance, and fuel economy. Applications include on-highway heavy-duty trucks, construction machinery, generator sets, and marine propulsion units equipped with the Cummins N855 big cam and small cam engine platforms.