Cummins ISM-400 Specifications
| Engine Model: Cummins ISM-400 |
| Engine Type: 4-cycle 6-cylinder CELECT electronic fuel-injection liquid-cooled diesel |
| Total Displacement: 661 cu.in (10.8 L) |
| Rated Engine Power: 400 Hp (298 kW) at 2000 rpm |
| Aspiration Type: Turbocharged |
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The Cummins ISM-400 is a high-output,
electronically controlled heavy-duty diesel engine designed for
demanding on-road, off-road, and industrial duty cycles. As part of the
ISM/M11 engine family, the ISM-400 produces approximately 400 horsepower
with a long-stroke 11-liter configuration known for excellent low-RPM
torque, extended service life, strong fuel efficiency, and reliable
operation in severe environments.
Its durable cast-iron block, electronically managed unit-injector
system, high-flow turbocharger, and robust cooling infrastructure make
it suitable for long-haul trucking, construction equipment, municipal
machinery, agricultural tractors, generator sets, and industrial power
units. The engine’s CELECT/CELECT Plus electronic management system
enhances timing precision, emissions control, cold-start performance,
and diagnostic capabilities while supporting flexible calibration for
different applications.
The ISM-400 is a four-stroke, turbocharged, water-cooled inline-six
diesel engine with a displacement of 10.8 liters (661 cubic inches). Its
bore is 125 mm (4.92 in), and the stroke is 147 mm (5.79 in), creating a
long-stroke geometry that maximizes torque production and combustion
efficiency. The compression ratio varies between 16.1:1 and 17.0:1
depending on emissions configuration and calibration year.
Power rating for the ISM-400 is 400 hp (298 kW) at 1,800–2,100 rpm, and
peak torque ranges from 1,650–1,750 Nm (1,217–1,291 lb-ft) at
1,200–1,400 rpm. The firing order is 1-5-3-6-2-4. Idle speed is
approximately 600–700 rpm, and governed speed is typically 1,800–2,100
rpm. The forged-steel crankshaft is supported by seven main bearings,
each designed to withstand high cyclic loads during full-duty operation.
Pistons are cast-aluminum alloy with hardened crowns, reinforced
combustion bowls, and internal cooling galleries. Connecting rods are
heavy forged steel with replaceable bearings designed for repeated
overhaul cycles.
The turbocharging system incorporates a fixed-geometry or wastegated
turbocharger with a high-flow compressor wheel and oil-cooled bearing
housing. Charge-air cooling is provided by an air-to-air aftercooler
(ATAAC) that reduces intake temperature, increasing density and
supporting higher torque output while managing exhaust-gas temperatures.
Emissions versions may use cooled EGR to reduce NOx output, particularly
in EPA 2004 variants.
The ISM-400 cylinder block is constructed from high-strength cast iron
with a deep-skirt design that significantly enhances structural
rigidity. Parent-bore cylinders are machined directly into the block and
surrounded by full-coverage water jackets that maintain stable operating
temperatures during long service intervals. Reinforced ribbing minimizes
block flex, vibration, and harmonics during high-load operation.
Wide main-bearing saddles distribute crankshaft
forces evenly and prolong engine life during repeated high-stress
cycles. The block is engineered to support multiple remanufacture cycles
with standard machining practices, making it ideal for fleets requiring
long-term serviceability and predictable operating costs.
The cast-iron cylinder head contains two valves per cylinder–one intake
and one exhaust–optimized for direct-injection combustion efficiency.
Hardened valve seats and guides protect against wear under high thermal
and mechanical loads. The mechanical rocker-arm valvetrain allows for
precise manual valve-lash adjustments using conventional workshop
techniques.
Cold valve-lash settings are typically:
– Intake: 0.25 mm (0.010 in)
– Exhaust: 0.50 mm (0.020 in)
The head design supports high boost pressures and elevated exhaust
temperatures, enabling the engine to withstand continuous heavy-duty use
in vocational trucks, loaders, generators, and industrial applications.
The ISM-400 uses electronically managed unit injectors under CELECT,
CELECT Plus, or CM875 control depending on model year. These systems
deliver precise control over injection timing, duration, and fuel
quantity, improving fuel efficiency, torque response, and emissions
performance.
Fuel-system components include:
– Electronically actuated unit injectors
– ECM-controlled timing maps
– Gear-driven transfer pump
– Primary and secondary fuel filters
– Water separator
– Fuel-pressure and fuel-temperature sensors
Injection pressures effectively reach 1,200–1,600 bar equivalent during
injection events. Pilot-injection strategies reduce noise and improve
idle quality. The digital ECU also supports diagnostics, engine
protection parameters, and derate strategies for overheating, low oil
pressure, or boost irregularities.
The ISM-400 uses a full-pressure, wet-sump lubrication system driven by
a high-capacity gear pump. Oil is delivered to the crankshaft, camshaft,
valvetrain, injector cam follower assemblies, and piston cooling jets.
Oil capacity ranges from 27–34 liters (28–36 qt).
Recommended operating oil pressures are:
– 275–380 kPa (40–55 psi) at rated speed
– 70–100 kPa (10–15 psi) at idle
Recommended lubricants include SAE 15W-40 oil meeting API CI-4, CJ-4, or
CK-4 specifications. Oil-change intervals vary from 250 hours in
industrial applications to 24,000–32,000 km for on-road trucks depending
on load conditions, fuel quality, and duty cycle.
The ISM-400 cooling system includes:
– Belt-driven centrifugal water pump
– Engine-oil cooler
– Full-jacket coolant passages
– Thermostat-regulated coolant flow
– Radiator or remote-cooling provision
– Air-to-air charge-air cooler
Thermostat values:
– Begins opening at 82°C (180°F)
– Fully open at approximately 95°C (203°F)
Cooling-system capacity typically ranges between 30–40 liters (32–42
qt). Proper cooling is critical for maintaining combustion stability,
reducing thermal stresses, and supporting high boost pressures under
sustained heavy load.
The ISM-400 may be equipped with several
auxiliary or application-specific support systems:
– PTO drive pads
– Air-compressor drive for truck braking systems
– Hydraulic pump mounts
– Remote radiator connections for industrial units
– Multiple SAE flywheel housing options
– ECM-controlled idle and torque-limit functions
– EGR systems (in later EPA-compliant models)
Electrical and electronic systems include crankshaft and camshaft
position sensors, coolant-temperature sensors, oil-pressure sensors,
MAP/boost sensors, and intake-air-temperature sensors. Alternators
typically range between 60–120 amps depending on application
requirements.
Approximate physical dimensions:
– Length: 1,250–1,400 mm (49–55 in)
– Width: 800–950 mm (31–37 in)
– Height: 1,100–1,250 mm (43–49 in)
Dry weight: 900–1,050 kg (1,984–2,315 lb).
These dimensions make the ISM-400 suitable for vocational trucks, buses,
graders, loaders, cranes, and industrial power units requiring an
11-liter performance envelope.
Routine maintenance intervals:
– Oil and filter: 250 hr or 24,000–32,000 km
– Fuel filters: 250–300 hr
– Air-filter service: inspect every 50–100 hr
– Valve-lash adjustment: every 1,000 hr
– Injector calibration: 1,200–2,000 hr
– Coolant replacement: every 2 years
– Compression testing: every 2,000 hr
– Belt inspection: every service interval.
– Cylinder-head bolts: 270–300 Nm (199–221 lb-ft) + angle
– Main-bearing caps: 400–450 Nm (295–332 lb-ft)
– Connecting-rod bolts: 110–130 Nm (81–96 lb-ft)
– Flywheel bolts: 220–260 Nm (162–192 lb-ft)
– Crankshaft-damper bolt: 400–480 Nm (295–354 lb-ft)
– Injector hold-down: 25–30 Nm (18–22 lb-ft)
– Oil-drain plug: 40–55 Nm (30–41 lb-ft).
The ISM-400 is used widely in:
– Class-7 and Class-8 trucks (Kenworth, Peterbilt, Freightliner,
International)
– Vocational vehicles (dump trucks, mixers, refuse trucks, utility
trucks)
– City and intercity buses
– Agricultural tractors and sprayers
– Construction machinery (wheel loaders, graders, cranes)
– Industrial power units and compressors
– Generator sets (ISM-G variants)
– Oilfield equipment
– Fire trucks and emergency vehicles.
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