Cummins ISM-350 Specifications
| Engine Model: Cummins ISM-350 |
| Engine Type: 4-cycle 6-cylinder CELECT electronic fuel-injection liquid-cooled diesel |
| Total Displacement: 661 cu.in (10.8 L) |
| Rated Engine Power: 350 Hp (261 kW) at 2000 rpm |
| Aspiration Type: Turbocharged |
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The Cummins ISM-350 is part of the ISM/M11
engine family, a modernized evolution of the earlier M11 and L10
engines. It is an 11-liter, electronically controlled, heavy-duty
inline-six diesel engine widely used in highway trucks, buses, municipal
vehicles, vocational machinery, agricultural machines, construction
equipment, and industrial power units. The ISM-350 specifically refers
to engines calibrated for approximately 350 horsepower, typically
optimized for line-haul trucking, vocational service, and demanding
industrial environments.
Known for strong torque at low and mid-range speeds, the ISM-350
delivers reliable operation, excellent fuel efficiency for its class,
and long overhaul intervals. Its electronically controlled fuel system
(CELECT and later CELECT Plus/CM875 ECMs), robust cast-iron
architecture, and advanced air-handling systems make it suitable for
heavy-duty workloads requiring long-term durability and dependable
service.
The ISM-350 is a four-stroke, water-cooled, turbocharged inline
six-cylinder diesel engine. Displacement is 10.8 liters (661 cubic
inches). Bore is approximately 125 mm (4.92 in) and stroke is 147 mm
(5.79 in), producing a long-stroke geometry designed to maximize torque
and efficiency. Compression ratio: typically 16.1:1–17.0:1 depending on
emissions version.
Power and torque:
– Rated power (ISM-350): 350 hp (261 kW) @ 1,800–2,100 rpm
– Peak torque: 1,550–1,650 Nm (1,143–1,217 lb-ft) @ 1,200–1,400 rpm
Idle speed: 600–700 rpm
Governed speed: 1,800–2,100 rpm
Firing order: 1-5-3-6-2-4.
Turbocharging:
– Fixed-geometry or wastegated turbocharger depending on calibration
– Oil-cooled bearing housing
– High-flow compressor for mid-range torque performance
Emissions capability varies by production
year, including:
– Pre-EPA
– EPA 98
– EPA 2002
– EPA 2004 (with cooled EGR)
The cylinder block is a high-strength cast-iron structure designed for
continuous high-load applications.
Key features:
– Parent-bore cylinders
– Deep-skirt architecture for rigidity
– Reinforced structural ribbing
– Full-coverage coolant jackets
– Seven main bearings supporting the forged-steel crankshaft
The block is engineered for multiple overhauls and long service life,
even under severe duty cycles.
The cast-iron cylinder head includes:
– Two valves per cylinder (intake and exhaust)
– Direct-injection combustion chambers
– Hardened valve seats and guides
– Rocker-arm operated valvetrain
Cold valve lash:
– Intake: 0.25 mm (0.010 in)
– Exhaust: 0.50 mm (0.020 in)
The head is designed to withstand high cylinder pressures and prolonged
thermal loading from turbocharged operation.
The ISM-350 uses CELECT or CELECT Plus electronic fuel-injection systems
depending on model year.
Key components:
– Electronically controlled unit injectors
– ECM-controlled timing and metering
– Fuel-transfer pump
– Dual-stage filtration with water separator
– Fuel-pressure and temperature sensors
Injection pressures:
– High-pressure electronic injectors deliver precise metering and timing
– Typical peak pressures: 1,200–1,600 bar depending on injector model
Fuel-system maintenance:
– Replace filters every 250–300 hr
– Drain water separator daily
– Injector test every 1,200–2,000 hr
– ECM recalibration when required.
The ISM-350 uses a full-pressure, wet-sump lubrication system.
Oil capacity: 27–34 liters (28–36 qt)
Operating oil pressure: 275–380 kPa (40–55 psi)
Idle pressure: 70–100 kPa (10–15 psi)
Recommended oil:
– SAE 15W-40
– API CI-4, CJ-4, or CK-4
Oil-change intervals:
– Industrial: 250 hr
– On-road: 24,000–32,000 km depending on duty cycle.
The cooling system includes:
– Belt-driven centrifugal water pump
– Thermostat-regulated coolant flow
– Full water-jacket coverage
– Oil cooler
– Radiator or remote-cooling capability
– Optional charge-air cooling (air-to-air) for higher-output
calibrations
Thermostat settings:
– Opening: 82°C (180°F)
– Fully open: 95°C (203°F)
Cooling capacity: 30–40 liters (32–42 qt)
System pressure: 70–100 kPa (10–15 psi).
| Intake and Exhaust Systems |
Turbocharging system includes:
– High-flow fixed-geometry turbocharger
– Optional wastegate for improved altitude compensation
Charge-air cooling:
– Air-to-air aftercooling is standard on most ISM-350 applications
Air intake system:
– Dry-type air filter
– Optional dual-stage filtration
– Optional cyclone pre-cleaner for dusty environments
Exhaust system:
– Cast-iron manifold
– Optional EGR system (EPA 2004 models)
– Marine and stationary exhaust adaptors.
| Electrical and Electronic Systems |
The ISM-350 uses CELECT or CELECT Plus ECM
(later CM875) to manage:
– Injection timing and fuel metering
– Idle control
– Diagnosing and logging fault codes
– Cold-start timing adjustment
– EGR system (if equipped)
– Turbocharger boost logic (on wastegated calibrations)
Sensors include:
– Crankshaft and camshaft position sensors
– Coolant-temperature sensor
– Oil-pressure sensor
– Intake air temperature sensor
– Boost/MAP sensor
– Fuel-temperature and fuel-pressure sensors
Electrical characteristics:
– 12V or 24V starting systems
– Alternator output: 60–120 amps depending on application.
Optional systems include:
– PTO pads for hydraulic drives
– Air-compressor drive (truck applications)
– Generator-housing adaptors
– Remote radiator connections
– Industrial accessory-drive packages
– Front- and rear-mounted SAE housings.
Approximate 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).
Routine service intervals:
– Oil and filter: 250 hr
– Fuel filters: 250–300 hr
– Air-filter inspection: every 50–100 hr
– Valve-lash adjustment: every 1,000 hr
– Injector calibration: every 1,200–2,000 hr
– Coolant replacement: every 2 years
– Compression testing: every 2,000 hr
– Belt inspection: each 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)
– Oil-drain plug: 40–55 Nm (30–41 lb-ft)
– Injector hold-down: 25–30 Nm (18–22 lb-ft).
The Cummins ISM-350 is widely used in:
– Class-7 and Class-8 trucks (Kenworth, Peterbilt, Freightliner,
International, Volvo)
– City and intercity buses
– Vocational vehicles (dump trucks, mixers, refuse trucks)
– Agricultural tractors
– Construction machinery (wheel loaders, graders, loaders)
– Industrial power units
– Generator sets (ISM-G)
– Oilfield equipment
– Municipal and government fleets.
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