: Because of its reliable mechanical nature, it is a staple for heavy-duty trucks, marine vessels, and industrial power generators. Technical Specifications Summary Displacement 14.0L (855 cubic inches) Configuration Inline 6-cylinder diesel Horsepower 250 – 475 HP (depending on configuration) Torque 1,000 – 1,650 lb-ft Oil Capacity Approx. 11 to 15 gallons (44–57L) NTA855-G4 - Cummins

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

: 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.

: 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.

: It uses the Cummins Pressure-Time (PT) self-adjusting fuel system, which provides accurate metering and timing through camshaft-actuated injectors. Performance and Durability