Cummins L10-280 Specifications
| Engine Model: Cummins L10-280 |
| Engine Type: 4-stroke in-line 6-cylinder turbocharged liquid-cooled diesel |
| Total Displacement: 611 cu.in (10.0 L) |
| Rated Engine Power: 280 Hp (207 kW) at 2100 rpm |
| Fuel System Type: Mechanical Pressure-Time (PT) |
____________________________________________________________________________________
The Cummins L10-280 represents a significant
engineering milestone for Cummins Inc., serving as the company’s first
production engine to utilize an overhead camshaft (OHC) design.
Introduced in the late 1980s and refined throughout the 1990s, this
10.0-liter inline-6 diesel engine was developed to bridge the gap
between the smaller 8.3-liter engines and the heavier, traditional
14-liter NT series.
The L10 was designed with a focus on weight reduction, serviceability,
and fuel efficiency, making it a dominant powerplant in regional haul
trucks, transit buses, and vocational applications. The 280 horsepower
variant is particularly revered for its balance of drivability and
durability, offering robust torque characteristics in a compact,
wet-sleeved package that simplified in-frame overhauls. Its mechanical
fuel system, while pre-dating electronic controls, provided a reputation
for reliability and straightforward troubleshooting.
Engine Type: Inline 6-cylinder, 4-stroke overhead cam turbocharged
diesel
Displacement: 10.0 L (611 cu.in)
Horsepower: 280 hp (207 kW) @ 2,100 RPM
Peak Torque: 950 lb-ft (1,288 Nm) @ 1,300 RPM
Bore x Stroke: 125 mm x 136 mm (4.92 in x 5.35 in)
Compression Ratio: 16.0:1 to 16.7:1 (dependent on specific piston and
injector build)
Aspiration: Turbocharged with air-to-air aftercooling
Fuel System: Mechanical Pressure-Time (PT) fuel system
Dry Weight: 891 kg (1,965 lbs)
Oil Capacity: 38-40 L (9.5-11 gal)
Cooling System Capacity (Engine Only): 12.5 L (13.2 qt)
The cylinder block is constructed from high-grade cast iron to provide a
rigid foundation for the internal components. It utilizes a deep-skirt
design for enhanced structural support under high cylinder pressures.
The L10 block is engineered with an open-deck configuration to
accommodate the wet-sleeve liner system.
The crankcase features a large, ribbed architecture to dampen vibrations
and improve overall noise, vibration, and harshness (NVH)
characteristics. The block incorporates integral mounting points for the
overhead camshaft housing and front gear train.
A defining feature of the L10 series is its one-piece, cross-flow cast
iron cylinder head. This head houses the overhead camshaft, which
actuates the valves via low-mass followers. The valve train consists of
four valves per cylinder - two intake and two exhaust - optimizing
airflow and combustion efficiency. The overhead cam design eliminates
the need for pushrods, reducing reciprocating mass and allowing for more
precise valve timing.
Valve bridges are utilized to ensure simultaneous actuation of the
paired valves. The cylinder head is sealed to the block via a
multi-layer steel (MLS) head gasket, designed to withstand the thermal
and mechanical stresses of turbocharged operation. Valve stems are
equipped with positive-type rotators to extend service life by
minimizing localized wear.
The L10-280 employs the Cummins Pressure-Time (PT) mechanical fuel
system. This system operates on the principle that fuel flow is a
function of pressure and time. A gear-driven fuel pump supplies fuel at
a controlled pressure to the injectors. Unlike unit injector systems,
the PT system uses a single, low-pressure supply pump to feed all
injectors, which are mounted in the cylinder head.
Fuel is drawn from the tank, passes through a filter, and is delivered
to the fuel pump, where pressure is regulated based on engine speed and
load. The fuel is then sent to the injectors; each injector utilizes a
simple plunger and barrel design to meter and inject fuel directly into
the combustion chamber. Excess fuel circulates back to the tank,
providing a cooling effect for the injectors.
The lubrication system is a full-pressure, full-flow design utilizing a
gear-type pump mounted internally to the timing gear housing. The pump
draws oil from the sump through a suction tube and screen, pushing it
through a full-flow spin-on filter before routing it to the main oil
gallery. From the main gallery, oil is distributed to the crankshaft
main bearings, connecting rod bearings, and camshaft bearings.
A dedicated oil jet system is aimed at the underside of the pistons to
provide cooling and lubrication to the piston pins. The system is
equipped with a bypass valve to ensure continued lubrication in the
event of filter blockage. Oil pressure is regulated by a spring-loaded
relief valve located within the pump housing.
The cooling system is a water-cooled, pressurized system designed to
maintain optimal operating temperatures under sustained load. The
centrifugal water pump is mounted on the front of the engine and is
gear-driven. Coolant flows from the pump into the cylinder block,
circulating around the wet cylinder liners through strategically placed
cooling orifices to ensure uniform heat dissipation.
The coolant then rises into the cylinder head, passing through the
complex passages surrounding the exhaust ports and injector sleeves
before exiting through the thermostat housing to the radiator. The L10
utilizes a non-asbestos gasket material for the water pump and
thermostat housing. Due to the wet-sleeve design, the system requires
the use of a supplemental coolant additive (SCA) to prevent cavitation
erosion and liner pitting.
Electrical System: Standard configuration includes a 12-volt or 24-volt
starting system, depending on the application (truck vs. bus). The
engine is equipped with a 28-volt, 50-amp alternator typically, though
higher output units were common for transit bus applications.
Air Intake System: Air is drawn through a dry-type air cleaner, passes
through the turbocharger compressor, and is then directed through the
air-to-air aftercooler (charge air cooler) before entering the cylinder
head. This reduces intake air temperature to increase air density for
efficient combustion.
Governor: A mechanical, all-speed governor is integrated into the PT
fuel pump system. It maintains the desired engine speed regardless of
load variations by controlling fuel pressure to the injectors.
Crankcase Ventilation: The engine utilizes a closed crankcase
ventilation system, routing blow-by gases through a breather tube into
the engine air intake to be reburned.
Overall Length (from fan to flywheel housing): 1,194 mm (47.0 in)
Overall Width: 889 mm (35.0 in)
Overall Height: 1,080 mm (42.5 in)
Dry Weight: 891 kg (1,965 lbs)
Oil Change Interval: 500 hours or 24,000 km (15,000 miles) under normal
operating conditions. Oil Filter: Spin-on full-flow filter. Replacement
interval coincides with oil change. Fuel Filter: Spin-on primary and
secondary filters. Replacement interval is 400 hours or 19,000 km
(12,000 miles).
Valve Lash Adjustment (Cold): Intake: 0.36 mm (0.014 in); Exhaust: 0.69
mm (0.027 in). Adjustment is performed on a cold engine. Coolant
Maintenance: Supplemental coolant additive (SCA) levels must be tested
and maintained at each oil change to prevent cylinder liner cavitation.
Coolant replacement interval is generally 2 years or 240,000 km (150,000
miles).
Cylinder Head Bolts: 176 Nm (130 lb-ft) + 180 deg rotation.
Connecting Rod Cap Bolts: 108 Nm (80 lb-ft) + 60 deg rotation.
Main Bearing Cap Bolts: 176 Nm (130 lb-ft) + 90 deg rotation.
Flywheel Housing to Block: 44 Nm (32 lb-ft).
Flywheel to Crankshaft: 136 Nm (100 lb-ft).
Fuel Injector Hold-Down Bolt: 68 Nm (50 lb-ft).
Rocker Arm Shaft Supports: 61 Nm (45 lb-ft).
Water Pump Mounting: 44 Nm (32 lb-ft).
Oil Pan Bolts: 41 Nm (30 lb-ft).
The versatility of the L10-280 allowed it to be utilized across a broad
spectrum of commercial vehicles.
Regional Haul Trucks: It was a popular powerplant in Freightliner
FL-series (FLD112), Kenworth T600A, and Peterbilt 375/378 models. The
engine’s weight advantage allowed for higher payload capacity compared
to larger-displacement engines.
Transit Buses: The L10-280 was a common specification in Gillig Phantom
and New Flyer D-series buses. The overhead cam design contributed to
lower engine height, facilitating the low-floor configurations required
for transit applications.
Vocational Vehicles: The engine saw extensive use in dump trucks,
concrete mixers, and refuse vehicles, particularly in chassis such as
the International 5000 series and Mack MR models.
Motor Coaches: Some MCI (Motor Coach Industries) and Prevost coaches
utilized the L10-280 for its combination of power and fuel economy in
intercity operations.
Fire Apparatus: The engine was also specified in some commercial chassis
fire trucks and rescue vehicles where a compact, reliable mid-range
engine was required.
____________________________________________________________________________________
| Industrial Engines Technical Specifications |
| Car Engines Technical Specifications |
| Small Engines Technical Specifications |
| Outboard Engines Technical Specifications |
