Cummins N14 Celect and Celect Plus

Cummins N14 Engine Specs, History, & Information

The Cummins N14 is one of many quintessential diesel engine platforms from renowned engine manufacturer Cummins Inc. It was produced from 1987 through 2001, where it was a relatively popular engine choice for class 7 and 8 on-highway applications. Originally utilizing an entirely mechanical injection system, the N14 eventually adopted the Cummins "Celect" and later "Celect Plus" electronically controlled fuel systems.

The original Cummins N14 featured a gear driven, mechanical injection pump and camshaft fired unit injectors. The system was know as the "PT" injection system, short for Pressure-Time. Chasing Detroit's popular 60 Series platform, specifically it's electronically controlled injection system, Cummins introduced the N14 "Celect" in 1990 (Cummins Electronic Engine Control). The N14 Celect relies on electronically controlled, camshaft driven unit injectors. In the system, the camshaft provides final fuel pressure in each individual fuel injector but the injectors utilize electronic solenoids that are actuated by the ECM. The result is greater timing, pulse width, and pressure control. For 1997 Cummins introduced the N14 "Celect Plus", which essentially features a more sophisticated ECM and injection management system.

Cummins N14 Engine Specs


Cummins Inc.


1987 - 2001 class 7/8 on-highway trucks

Engine Type:

4 cycle turbodiesel


Inline 6 cylinder


855 CID, 14.0 liters

Firing Order:

1 - 5 -3 - 6 -2 - 4

Engine Block:

Cast iron, wet cylinder liners

Cylinder Head:

Cast iron

Compression Ratio:

14.0 to 17.0 : 1

Cylinder Bore:

5.5 in (140 mm)

Cylinder Stroke:

6.0 in (152 mm)


Overhead valve (OHV), 4 valves per cylinder


1987 - 1989

Mechanical injection pump, camshaft controlled mechanical unit injectors, pressure-time (PT) injection system

1990 - 1996

Cummins Celect electronically controlled injected system, electronically actuated unit injectors

1997 - 2001

Celect Plus electronically controlled injection system (more sophisticated ECM, diagnostic features than previous Celect system)


Holset turbocharger, air-to-air intercooler (charge air cooler)

Engine Dimensions (approx.):


59 in


37 in


51 in

Engine Weight (approx):

2,550 to 2,625 lbs dry | 2,650 to 2,750 lbs wet

Min Oil Pressure:

10 psi @ low idle
35 - 45 psi @ governed speed, no load

Engine Oil Capacity:

11.0 U.S. gallons (common for applications w/ bypass filter, oil capacity may vary)

Rated Horsepower:

310 - 525 hp @ 1,800 - 2,100 RPM

Rated Torque:

1,250 - 1,850 lb-ft @ 1,200 RPM

Max Engine Speed:

2,100 RPM