Cummins M11 Specifications
| Engine Model: Cummins M11 |
| Engine Type: 4-cycle inline 6-cylinder direct injection liquid-cooled diesel |
| Total Displacement: 661 cu.in (10.8 L) |
| Rated Engine Power: 220-400 Hp (164-298 kW) at 2000 rpm |
| Aspiration Type: Turbocharged |
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The Cummins M11 is an 11-liter, heavy-duty,
inline six-cylinder diesel engine used extensively in highway trucks,
buses, construction equipment, agricultural machinery, and industrial
power units. Introduced as an evolution of the L10 platform, the M11
offered increased displacement, higher torque output, and improved
durability. Early M11 versions use mechanical PT fuel-injection (M11
CELECT was one of the first electronically-controlled heavy-duty Cummins
engines).
The M11 platform is known for reliability, long
overhaul intervals, good fuel efficiency for its displacement, and
simplified maintenance procedures. It remains widely used in legacy
fleets, stationary equipment, and rebuilt commercial trucks across the
world.
The Cummins M11 is a four-stroke, turbocharged, water-cooled inline
six-cylinder diesel engine. Displacement is 10.8 liters (661 cubic
inches). Bore is about 125 mm (4.92 in) and stroke approximately 147 mm
(5.79 in), yielding a long-stroke design for high torque output.
Compression ratio: typically 16.1:1 to 17.0:1 depending on
configuration.
Power ratings:
– Highway trucks: 280–400 hp (209–298 kW) @ 1,800–2,100 rpm
– Buses and vocational vehicles: 260–350 hp (194–261 kW)
– Industrial/agricultural: 220–350 hp (164–261 kW)
– Generator-drive: 150–260 kW @ 1,500–1,800 rpm
Peak torque: 1,350–1,750 Nm (996–1,291 lb-ft) @ 1,200–1,500 rpm
Idle speed: 600–700 rpm
Governed speed: 1,800–2,100 rpm
Firing order: 1-5-3-6-2-4.
The M11 uses a heavy-duty cast-iron block
with:
– Parent-bore cylinders
– Deep-skirt construction
– Structural ribbing for stiffness
– Full water-jacket cooling
– Wide main-bearing saddles
The block is optimized for long-duration load conditions and supports
multiple cylinder rebores.
The cast-iron cylinder head includes:
– Two valves per cylinder
– Direct-injection combustion chamber
– Hardened valve seats and guides
– Rocker-arm valvetrain with mechanical adjustment
Cold valve-lash specifications:
– Intake: 0.25 mm (0.010 in)
– Exhaust: 0.50 mm (0.020 in).
The M11 used two major fuel-system generations:
Mechanical PT Injection (early M11)
– PT fuel pump
– Mechanical governor
– High-flow injectors
– Dual-stage filtration
CELECT / CELECT Plus Electronic Injection
(later M11)
– ECM-controlled electronic injectors
– Timing and metering optimized electronically
– Improved emissions control and diagnostics
Standard injection pressures:
– Mechanical PT: 250–400 bar
– CELECT electronic: significantly higher peak injection pressure
Fuel-system maintenance:
– Filters: 250–300 hr
– Water separator: daily drain
– Injector test: 1,200–1,800 hr
– Pump/injector calibration: major service.
Full-pressure lubrication with gear-driven oil pump and full-flow/bypass
filtration.
Oil capacity: 27–34 liters (28–36 qt)
Oil pressure:
– Operating: 275–380 kPa (40–55 psi)
– Idle: 70–100 kPa (10–15 psi)
Recommended lubricants:
– SAE 15W-40
– API CI-4, CJ-4, CK-4
Oil change interval: 250 hr industrial; 20,000–30,000 km for on-road
trucks.
Includes:
– Belt-driven centrifugal water pump
– Thermostat-controlled coolant flow
– Heavy-duty radiator or remote cooling
– Oil cooler
Thermostat:
– Opens at 82°C (180°F)
– Fully open at 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:
– Fixed-geometry turbocharger
– Oil-lubricated center housing
– Designed for high boost durability
Aftercooling:
– Air-to-air or air-to-water charge-air cooling depending on application
Air filtration:
– Dry-type filters
– Optional dual-stage elements
Exhaust:
– Cast-iron manifold
– Heavy-duty industrial exhaust elbows.
| Electrical and Electronic Systems |
Mechanical versions:
– 12V or 24V start system
– 35–70 A alternator
CELECT electronic versions:
– ECM controls fuel injection and timing
– Sensors include:
- Crankshaft and camshaft position
- MAP/boost
- Coolant temperature
- Oil pressure
- Intake air temperature
– ECM provides diagnostic fault codes.
Options include:
– PTO drive pads
– Hydraulic pump mounts
– Air-compressor drive
– Remote radiator piping
– Generator housing adaptors
– Front/rear accessory drives.
Approximate engine 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).
Service intervals:
– Oil and filter: 250 hr
– Fuel filters: 250–300 hr
– Air filter: inspect 50–100 hr
– Valve-lash adjustment: 1,000 hr
– Injector calibration: 1,200–2,000 hr
– Coolant: replace every 2 years
– Compression test: every 2,000 hr.
– Cylinder-head bolts: 270–300 Nm (199–221 lb-ft) + angle
– Main-bearing caps: 400–450 Nm (295–332 lb-ft)
– Connecting rods: 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 M11 is used in:
– Freightliner, Kenworth, Peterbilt, International trucks
– City and intercity buses
– Agricultural tractors
– Wheel loaders and construction machinery
– Industrial power units
– Pumps and compressors
– Generator sets (150–260 kW)
– Oilfield equipment
– Municipal and vocational vehicles.
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