: Unlike modern engines, the NT855 lacks complex Electronic Control Modules (ECMs). This makes it significantly easier to diagnose and repair using standard mechanical tools, which is ideal for remote locations.
: The manual's maintenance schedules support an engine capable of logging over 1 million miles or 700,000 miles before a major overhaul is expected. Cummins Engine Nt855 Manual
: The cylinder liners are "wet," meaning they are in direct contact with coolant for better heat dissipation. This design allows for easier rebuilds because the liners can be replaced without needing to machine the engine block. : Unlike modern engines, the NT855 lacks complex
: The engine features an alloy cast iron block and head, forged-steel internals, and large bearings designed for extreme durability. : The cylinder liners are "wet," meaning they
The Cummins NT855 engine is widely regarded as a legendary workhorse, and its manual highlights a "mechanical-first" design that makes it exceptionally reliable and user-friendly for heavy-duty applications. Key Design Features
: It uses the Cummins Pressure-Time (PT) self-adjusting fuel system, which provides accurate metering and timing through camshaft-actuated injectors. Performance and Durability
: The "Big Cam" evolution increased the camshaft diameter to 2.5 inches, shortening injection periods to create more torque at lower engine speeds and improving fuel efficiency.