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Cummins ISB6.7E5 Specifications
| Engine Model: Cummins ISB6.7E5 |
| Engine Type: 4-cycle inline 6-cylinder common-rail direct injection liquid-cooled diesel |
| Total Displacement: 409 cu.in (6.7 L) |
| Rated Engine Power: 197-273 Hp (147-204 kW) at 2300 rpm |
| Aspiration Type: Turbocharged and aftercooled |
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| General Technical Data |
The Cummins ISB6.7E5 is a modern, electronically controlled, turbocharged and aftercooled, inline six-cylinder diesel engine designed to meet Euro 5 emissions standards for medium-duty trucks, buses, vocational vehicles, agricultural machinery, construction equipment, and industrial platforms. As part of the Cummins ISB/ISBe engine family, the ISB6.7E5 incorporates advanced combustion design, high-pressure common-rail fuel injection, cooled exhaust gas recirculation (EGR), optimized air handling, and sophisticated engine control strategies to deliver excellent fuel efficiency, low emissions, strong torque across the operating range, and reliable long-term performance.
This engine is widely used globally due to its
balance of power, efficiency, parts availability, and ease of
integration into multiple vehicle and machinery types. Its robust
cast-iron construction, electronically managed systems, and durable
auxiliary components make it suitable for heavy-duty and stop-and-go
applications.
The Cummins ISB6.7E5 is a four-stroke, inline six-cylinder diesel engine
with a displacement of approximately 6.7 liters (409 cubic inches). Bore
is typically 107 mm (4.21 inches), while stroke measures about 124 mm
(4.88 inches), forming a long-stroke architecture optimized for torque
production and fuel efficiency. Compression ratio varies slightly by
calibration but generally falls between 16.5:1 and 17.3:1.
Power output commonly ranges between 147 and
204 kW (197–273 horsepower) at roughly 2300 rpm. Peak torque generally
ranges from 700 to 1100 Nm (516–811 lb-ft), usually achieved around
1400–1600 rpm. Idle speed is normally set around 750 ± 50 rpm. The
firing order is 1–5–3–6–2–4. The combination of high-pressure
common-rail injection, EGR, turbocharging, and precise electronic
control enables cleaner combustion, reduced noise, and improved
transient response.
The cylinder block is cast from high-strength gray iron engineered to
withstand increased cylinder pressures associated with modern emissions
technology and high-power calibrations. Deep reinforcement ribs minimize
distortion and vibration. The forged-steel crankshaft rides on seven
main bearings designed for long-term service life and reduced torsional
vibration.
Piston cooling jets are incorporated into the
block to regulate combustion temperatures and extend piston life under
heavy load. Cast-in coolant jackets provide uniform cooling, while
machined oil galleries distribute lubrication to the crankshaft,
connecting rods, camshaft bearings, and other critical components.
Threaded accessory bosses support mounting of pumps, alternators,
air-conditioning compressors, and power take-off devices.
The cast-iron cylinder head incorporates advanced combustion chamber
geometry optimized for efficient fuel-air mixing. The head features four
valves per cylinder–two intake and two exhaust–improving airflow and
supporting stronger torque and cleaner combustion. Valve actuation is
controlled by rocker arms and pushrods connected to a camshaft mounted
in the block. Depending on configuration, hydraulic lash adjusters may
be equipped, reducing the need for periodic valve adjustments.
Hardened valve seats and high-temperature-resistant guides ensure durability under elevated EGR and turbocharger heat loads. Integrated coolant passages stabilize head temperature and reduce thermal stress, improving long-term durability. The head gasket design accommodates increased peak cylinder pressures required for Euro 5 emissions compliance.
| Fuel System |
The ISB6.7E5 uses a high-pressure common-rail fuel system. A low-pressure lift pump feeds fuel through filtration stages to a high-pressure pump capable of generating rail pressures above 1600–1800 bar (23,200–26,000 psi). Electronically actuated fuel injectors deliver precisely metered fuel via multiple injection events to reduce noise, improve cold starts, enhance power, and lower particulate emissions.
The electronic control module (ECM) continuously monitors crankshaft and camshaft position, rail pressure, boost pressure, intake temperature, coolant temperature, EGR flow, and exhaust temperature to determine optimal injection quantity, pressure, and timing. Fuel filtration includes primary water-separating filters and high-efficiency secondary filters to protect injectors from contamination. The system is engineered to support clean, efficient combustion even under varying load and environmental conditions.
| Lubrication System |
The lubrication system is a full-pressure wet-sump design using a high-capacity gear-driven oil pump. The pump draws oil through a metal-mesh strainer and pushes it through a full-flow filter before reaching the main gallery. Lubrication is supplied to the crankshaft main bearings, connecting rod journals, camshaft bearings, rocker arms, turbocharger bearings, and auxiliary drives. Piston-cooling jets help manage piston temperature during continuous heavy-duty operation.
Normal operating oil pressure typically ranges from 300 to 500 kPa (44–72 psi), while idle pressure ranges from 100 to 150 kPa (15–22 psi). Oil capacity generally ranges between 12 and 18 liters (12.7–19 US quarts), depending on sump configuration. Engines equipped with emissions systems typically require low-ash oil to protect aftertreatment components.
| Cooling System |
The engine uses a liquid cooling system featuring a belt-driven centrifugal water pump. Coolant is circulated through cast-in block and head passages to remove heat generated during combustion. A thermostat begins opening near 82°C (180°F) and is fully open around 95°C (203°F). Cooling system pressure usually ranges from 90 to 110 kPa (13–16 psi). Coolant capacity typically ranges from 15 to 25 liters (15.8–26.4 US quarts), depending on installation.
The turbocharged and EGR-equipped layout requires effective thermal management; therefore, radiator capacity, coolant condition, and airflow must be maintained properly. Charge-air cooling (air-to-air or air-to-water aftercooling) reduces intake temperature, improving efficiency and reducing NOx formation. The ECM monitors coolant temperature and can implement derate strategies to prevent overheating.
| Other Systems |
Turbocharging improves air density and supports high torque output. Depending on version, the turbocharger may be wastegated or variable-geometry (VGT). VGT units improve transient response, support precise EGR flow regulation, and aid in emissions control. The EGR system recirculates cooled exhaust gases into the intake to reduce combustion temperature and NOx emissions.
Aftertreatment components in Euro 5 configurations may include DOC (Diesel Oxidation Catalyst), DPF (Diesel Particulate Filter), and SCR (Selective Catalytic Reduction). The intake system uses a heavy-duty dry-element air filter, with optional dual-stage filtration. The exhaust manifold is cast iron and designed to withstand extreme thermal cycling. Electrical systems may use 12- or 24-volt configurations with alternators rated between 60 and 120 amperes. The ECM provides real-time diagnostics, protection features, and a wide range of programmable parameters.
| Dimensions and Weight |
Physical dimensions include:
Length: 1050–1250 mm (41.3–49.2 inches)
Width: 700–900 mm (27.6–35.4 inches)
Height: 1000–1250 mm (39.4–49.2 inches)
Dry weight generally ranges from 480 to 590 kg (1058–1301 lbs),
depending on emissions equipment, turbocharger type, and accessory
configuration. The compact, modular layout supports installation in
medium-duty trucks, buses, and industrial machinery.
| Maintenance Data |
Oil and filter changes are typically recommended every 500 hours or 15,000–25,000 km (9,300–15,500 miles), depending on duty cycle. Fuel filters should be replaced every 500 hours, with water separators drained routinely. Air filter service intervals vary from 250 to 500 hours depending on dust exposure. Coolant replacement is generally required every two years or during major service.
Valve lash inspection may be required on versions without hydraulic lifters. Aftertreatment systems require periodic cleaning and regeneration depending on usage. The ECM stores diagnostic codes and operational data, enabling predictive maintenance and simplified troubleshooting.
| Tightening Torques |
Cylinder head bolts: 180–210 Nm (133–155 lb-ft)
Main bearing caps: 150–180 Nm (111–133 lb-ft)
Connecting rod bolts: 70–90 Nm (52–66 lb-ft)
Flywheel bolts: 220–260 Nm (162–192 lb-ft)
Crankshaft pulley bolt: 240–280 Nm (177–207 lb-ft)
Injector hold-down: 20–25 Nm (15–18 lb-ft)
Intake heater or glow plug (if equipped): 10–15 Nm (7–11 lb-ft)
Oil drain plug: 30–40 Nm (22–30 lb-ft).
| Vehicle Applications |
The Cummins ISB6.7E5 is widely used in medium-duty trucks, buses, urban delivery vehicles, vocational trucks, agricultural tractors, wheel loaders, excavators, telehandlers, cranes, forestry machinery, generator sets, and industrial pumps. Its strong torque output, fuel efficiency, emissions compliance, and reliable operation make it one of the most versatile engines in the medium-duty segment.
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