Cummins NTC-290 Specifications
| Engine Model: Cummins NTC-290 |
| Engine Type: 4-stroke in-line 6-cylinder turbocharged liquid-cooled diesel |
| Total Displacement: 855 cu.in (14.0 L) |
| Rated Engine Power: 290 Hp (216 kW) at 2100 rpm |
| Fuel System Type: Pressure-Time fuel system |
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The Cummins NTC-290 represents a landmark in
heavy-duty diesel engineering, standing as a prominent member of the
renowned Cummins NH engine family. Introduced as a powerful and reliable
solution for the demanding on-highway trucking and industrial sectors,
this engine became synonymous with durability and longevity.
The “NT” designation denotes its turbocharged and aftercooled
configuration, a critical advancement that allowed for significant
increases in power density without compromising structural integrity.
The “C” in its nomenclature often relates to its “Commercial” or, in
later evolutions, its “Big Cam” design, which introduced improvements in
fuel economy, reduced emissions, and simplified maintenance.
The NTC-290 is celebrated for its robust, no-nonsense architecture. Its
hallmark is the Pressure-Time (PT) fuel system, a Cummins-exclusive
design that prioritizes simplicity and reliability over the complex,
high-pressure injection pumps found on competitor engines. This engine’s
operational character is defined by substantial low-end torque,
delivering peak pulling power at 1500 RPM, which allowed drivers to
maintain momentum on gradients with fewer downshifts.
While later electronic engines surpassed it in refinement, the NTC-290
remains a benchmark for mechanical dependability, with countless units
logging over a million miles. Its legacy is one of a workhorse engine
that balanced power, fuel efficiency, and serviceability for the
heavy-haul industry.
Engine Type: 4-cycle, In-line, 6-cylinder diesel.
Displacement: 14.0 L (855 cu.in).
Bore and Stroke: 140 mm x 152 mm (5.5 in x 6.0 in).
Aspiration: Turbocharged and Aftercooled.
Compression Ratio: 15.0:1.
Firing Order: 1-5-3-6-2-4.
Rated Power: 216 kW (290 HP) at 2100 RPM.
Maximum Torque: 1,139 to 1,261 Nm (840-930 lb-ft) at 1500 RPM.
Governed Speed: 2100 RPM (high idle); low idle is typically 600-650 RPM.
Braking: Equipped with an optional Jacobs Engine Brake (Jake Brake)
system, utilizing the engine’s valve train to provide auxiliary slowing
power for enhanced vehicle control and reduced service brake wear.
The cylinder block is a high-strength, cast-iron alloy construction
designed for maximum rigidity under high cylinder pressures. It features
a deep-skirt design, where the block extends below the crankshaft
centerline, providing superior support for the main bearing caps. The
block is of a parent-bore design, meaning the cylinders are machined
directly into the block casting without replaceable liners, though later
iterations of the NH family featured replaceable wet-type cylinder
liners.
The block incorporates integral cooling passages that direct coolant
flow around the upper portion of each cylinder to manage thermal stress.
Reinforced bulkheads at the main bearing journals ensure crankshaft
stability. The engine employs a rear gear train, with all accessory
drives - fuel pump, camshaft, and air compressor - located at the rear
of the block for simplified front-end serviceability and reduced
torsional vibration.
The cylinder head is a single, cast-iron unit covering all six
cylinders, contributing to the engine’s structural rigidity and
simplified sealing. It utilizes a cross-flow design where intake and
exhaust passages are on opposite sides, optimizing thermal efficiency
and volumetric flow. The head is secured to the block by high-strength,
induction-hardened cylinder head bolts arranged in a specific pattern to
ensure uniform clamping force across the sealing surface.
The valve train is a conventional overhead valve (OHV) system, actuated
by the camshaft through pushrods and rocker arms. Each cylinder features
one intake valve and one exhaust valve. Valve stem seals are utilized to
control lubrication consumption. The valve lash (clearance) is a
critical maintenance parameter, set with the engine cold. The engine is
designed to accommodate a Jacobs Engine Brake, which integrates into the
valve cover and uses solenoids to alter exhaust valve timing for braking
effect.
Intake Valve Lash: 0.36 mm (0.014 in).
Exhaust Valve Lash: 0.69 mm (0.027 in).
The Cummins NTC-290 utilizes the proprietary PT (Pressure-Time) fuel
system, a mechanical direct injection system distinct from conventional
unit injector or distributor pump systems. This system operates on the
principle that the quantity of fuel delivered to a cylinder is a
function of fuel pressure and the time the injector is open. A single,
gear-driven, low-pressure fuel pump (the PT pump) supplies fuel at a
pressure modulated by engine speed and throttle position. This fuel is
circulated through a common gallery within the cylinder head to the top
of each injector.
The injectors are mechanically actuated by the engine’s camshaft via
rocker arms. The system lacks a high-pressure injection pump, relying
instead on the PT pump to regulate pressure and the injector plunger to
create the high pressure required for injection. This design simplifies
the fuel system, reduces potential failure points, and provides reliable
operation. The injector setting, referring to the adjustment of the
injector rocker arm, is precise to ensure correct fuel delivery and
timing.
Injection Pump: Mechanical gear-driven PT (Pressure-Time) pump.
Injector Setting: 7.68 to 8.13 Nm (68-72 in-lb).
The lubrication system is a full-pressure, gear-type positive
displacement system designed to provide a constant supply of clean oil
to critical engine components. A gear-driven oil pump, mounted
internally, draws oil from the sump and forces it through a full-flow
oil filter before distribution. The system includes a piston cooling jet
system, which directs oil streams to the underside of each piston to
dissipate combustion heat, a crucial feature for a turbocharged,
high-output diesel.
Oil pressure regulation is maintained by a spring-loaded relief valve to
prevent over-pressurization, especially during cold starts. The oil pan
capacity varies significantly based on the chassis and application, with
deep-sump configurations used for on-highway trucks requiring extended
service intervals and shallow sumps for industrial or off-highway
installations.
Oil Pan Capacity: 19-57 L (5-15 U.S. gal).
Oil Pressure: 100 kPa (15 PSI) at low idle.
Oil Pressure: 275-480 kPa (40-70 PSI) at governed speed.
The cooling system is a pressurized, water-cooled design employing a
centrifugal water pump driven by the engine’s gear train. Coolant is
circulated through the cylinder block, cylinder head, and the
aftercooler (where intake air is cooled after the turbocharger) before
passing through a radiator for heat dissipation.
The system is equipped with a thermostat to maintain optimal operating
temperature, generally between 82-94°C (180-200°F), ensuring efficient
combustion and component longevity. Big Cam models featured high-flow
cooling configurations with improved water pump designs and enlarged
coolant passages to enhance heat rejection and reduce thermal stress on
the cylinder head and block.
Electrical System: Available in 12-volt or 24-volt configurations. The
system includes a heavy-duty alternator, a starter motor with a solenoid
shift mechanism, and necessary wiring for engine-mounted sensors. The
starter motor is designed for high-torque engagement to overcome the
high compression ratio of the engine.
Air Intake System: The turbocharger, a single, Holset-designed unit,
compresses intake air. This heated, compressed air then passes through
the aftercooler (a heat exchanger) where it is cooled before entering
the cylinder head. This process increases air density, allowing for more
efficient combustion and higher power output while lowering combustion
temperatures and NOx formation.
Air Compressor: A gear-driven, single or two-cylinder air compressor is
mounted to the rear gear train to supply compressed air for the
vehicle’s braking system and other pneumatic accessories. It is
typically plumbed into the engine’s cooling and lubrication systems.
0Net Weight (Dry): 1,345 kg (2,965 lb). This weight includes the
flywheel, alternator, and standard accessory equipment but excludes the
starter, air compressor, and fluids.
Length: 1,389 mm (54.7 in). Measured from the front face of the
accessory drive to the rear face of the flywheel housing.
Width: 914 mm (36.0 in). The maximum width is generally measured across
the turbocharger or the exhaust manifold.
Height: 1,298 mm (51.1 in). Measured from the bottom of the oil pan rail
to the highest point, which is typically the valve cover or the
turbocharger inlet.
Oil Change Interval: Varies based on duty cycle and oil analysis
results, but for on-highway applications, a standard interval is 15,000
km (10,000 miles) or 250 hours. Use API classification CD or higher,
with viscosity selected according to ambient temperature. Oil Filter
Change: Performed concurrently with each oil change. Fuel Filter Change:
Primary and secondary fuel filters are replaced at 30,000 km (20,000
miles) or 500 hours.
Valve Lash and Injector Adjustment: A critical service operation. Both
valve lash and injector timing must be adjusted with the engine cold.
The procedure requires a specific sequence based on the firing order and
cylinder position (valve overlap). The injector is set by torquing the
adjusting screw to the specified value to collapse a preload spring,
establishing the correct plunger travel.
Coolant Maintenance: Coolant should be tested and treated with
supplemental coolant additives (SCA) to prevent cavitation and
corrosion. Coolant replacement intervals are typically 150,000 km
(100,000 miles) or 2 years.
Cylinder Head Bolts: 230-250 Nm (170-185 lb-ft).
Connecting Rod Cap Nuts: 120-130 Nm (88-96 lb-ft).
Main Bearing Cap Bolts: 210-220 Nm (155-162 lb-ft).
Flywheel Housing to Block: 60-70 Nm (44-52 lb-ft).
Flywheel to Crankshaft: 170-180 Nm (125-133 lb-ft).
Rocker Arm Shaft Bracket Nuts: 110-120 Nm (81-89 lb-ft).
Injector Rocker Arm Adjusting Screw: 7.68-8.13 Nm (68-72 in-lb).
Valve Rocker Arm Adjusting Screw Locknut: 45-55 Nm (33-41 lb-ft).
Turbocharger Mounting Nuts: 35-40 Nm (26-30 lb-ft).
Fuel Pump Mounting Nuts: 40-45 Nm (30-33 lb-ft).
The Cummins NTC-290’s combination of power, durability, and
serviceability made it a preferred powerplant across a broad spectrum of
heavy-duty applications.
On-Highway Trucks: It was extensively used as a prime mover in Class 8
heavy-duty trucks, including applications for long-haul, regional
distribution, and heavy haulage. Models from manufacturers such as
Kenworth, Peterbilt, Freightliner, International, and Mack were commonly
equipped with this engine.
Buses: Used in intercity coaches and heavy-duty transit buses where
reliability and grade-climbing capability were essential.
Construction Equipment: Found in large off-highway machinery such as
articulated dump trucks, wheel loaders, motor graders, and excavators
where sustained power at low RPM was required.
Industrial: Applied in generator sets (gensets), industrial pumps, and
compressors where continuous, reliable operation at a fixed governed
speed was necessary.
Agricultural: Used in large, self-propelled agricultural equipment,
including combines and large tractors, benefiting from its high torque
rise and durability in dusty environments.
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