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Cummins 6LTAA9.5-G1 Specifications
| Engine Model: Cummins 6LTAA9.5-G1 |
| Engine Type: 4-cycle inline 6-cylinder direct injection liquid-cooled diesel |
| Total Displacement: 580 cu.in (9.5 L) |
| Rated Engine Power: 268-402 Hp (200-300 kW) at 1800 rpm |
| Aspiration Type: Turbocharged and aftercooled |
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| General Technical Data |
The Cummins 6LTAA9.5-G1 is a high-output, turbocharged and aftercooled, inline six-cylinder diesel engine engineered for heavy-duty generator applications, industrial machinery, large construction equipment, agricultural power units, and off-highway machinery requiring exceptional performance and endurance. As a member of the Cummins L Series engine family, the 6LTAA9.5-G1 is designed to deliver robust power, high torque at low and midrange engine speeds, strong load acceptance, and reliable continuous-duty operation.
With its large displacement, mechanical
simplicity, and heavy-duty component design, the 6LTAA9.5-G1 is widely
used in generator sets around the world due to its stable frequency
control, fuel efficiency, and long-term durability. The engine’s
turbocharged and aftercooled configuration enhances combustion
efficiency, reduces emissions for its class, and improves thermal
stability under sustained high-load environments.
The 6LTAA9.5-G1 is a four-stroke, inline six-cylinder diesel engine with
a total displacement of approximately 9.5 liters (580 cubic inches).
Bore typically measures around 116 mm (4.58 inches), while stroke is
approximately 148 mm (5.82 inches), forming a long-stroke design
optimized for torque generation. Compression ratio generally ranges from
16.5:1 to 17.5:1 depending on calibration. Power output for generator
applications usually falls between 200 and 300 kW (268–402 horsepower)
at 1500 and 1800 rpm ratings.
Peak torque typically ranges from 1200 to 1600
Nm (885–1180 lb-ft), commonly achieved at 1300–1500 rpm. The firing
order is 1–5–3–6–2–4. Idle speed is normally set around 650–750 rpm. The
turbocharger and aftercooler significantly increase air density into the
combustion chamber, improving combustion efficiency, reducing specific
fuel consumption, and supporting stable performance under continuous
full-load operation.
The cylinder block is constructed from high-strength cast iron designed
to withstand the intense firing pressures and mechanical loads
associated with large-displacement turbocharged engines. Reinforcement
ribs reduce block flexingi and enhance long-term structural stability.
The forged-steel crankshaft is supported by seven large main bearings,
which ensure smooth rotation at all operating speeds and support long
overhaul life.
Wet or replaceable cylinder liners may be used
depending on configuration, allowing easier rebuild and improved
cooling. Cast-in coolant passages evenly distribute heat removal around
all cylinders. Machined oil galleries supply lubrication to primary
bearings, connecting rod journals, piston cooling jets, and camshaft
bearings. Multiple mounting bosses support integration into generator
frames and industrial applications.
The cylinder head is cast from heavy-duty iron and designed for direct
injection diesel combustion. Each cylinder contains two intake and two
exhaust valves, controlled by rocker arms and pushrods driven by a
camshaft located in the block. Valve lash is manually adjustable and
must be inspected periodically.
Hardened valve seats and heat-treated guides tolerate high exhaust temperatures characteristic of turbocharged operation. The combustion chamber features an optimized swirl design that improves air–fuel mixing, increasing torque, reducing smoke, and enhancing cold-start capability. Integrated coolant passages stabilize the head temperature and reduce thermal stress.
| Fuel System |
The 6LTAA9.5-G1 employs a mechanical direct-injection fuel system suitable for harsh, remote environments where electronically controlled systems may be less desirable. A mechanical lift pump draws fuel from the tank through a water separator and primary filter, then delivers it to a high-pressure inline injection pump. The injection pump meters fuel delivery and sets injection timing.
Injection pressures usually range between 250 and 300 bar, providing adequate atomization for efficient combustion. Fuel is delivered to multi-hole injectors, and excess fuel returns to the tank for cooling. Some configurations use a boost-compensated fuel control device to adjust fuel delivery according to turbocharger pressure, preventing excessive smoke and supporting smooth load transitions.
| Lubrication System |
A full-pressure lubrication system ensures long-term reliability under heavy loads. A gear-driven oil pump draws oil from the sump through a mesh strainer and pushes it through a full-flow oil filter. Pressurized lubrication is supplied to the crankshaft bearings, connecting rod bearings, camshaft journals, rocker arms, turbocharger bearings, and piston-cooling jets.
Operating oil pressure typically ranges from 300 to 450 kPa (44–65 psi), while idle pressure generally ranges from 100 to 150 kPa (15–22 psi). Oil capacity typically ranges from 20 to 28 liters (21.1–29.6 US quarts). High-temperature-resistant lubrication is necessary for engines equipped with aftercoolers and heavy-duty turbochargers.
| Cooling System |
The cooling system is a closed-circuit liquid cooling arrangement featuring a belt-driven centrifugal water pump. Coolant flows through cast-in block and head jackets, removing heat and stabilizing the engine temperature. The thermostat begins opening around 82°C (180°F) and is fully open around 95°C (203°F). Cooling system pressure ranges from 90 to 110 kPa (13–16 psi).
Coolant capacity largely depends on installation but commonly ranges between 25 and 40 liters (26.4–42.3 US quarts). The aftercooler, utilizing either air-to-air or air-to-water designs, lowers intake charge temperature, increasing power density and combustion consistency. Regular inspection of cooling hoses, radiator fins, coolant quality, and aftercooler cleanliness is crucial to prevent overheating and maintain thermal efficiency.
| Other Systems |
Turbocharging boosts intake density, improving low- and midrange torque. Aftercooling lowers intake temperature and increases charge-air density. The air intake system includes a heavy-duty dry-element air filter, with dual-stage options for dusty sites. The exhaust manifold is constructed of heat-resistant cast iron designed to handle extreme thermal cycling.
Electrical systems operate on 12- or 24-volt configurations, typically incorporating alternators rated between 50 and 120 amperes. A reduction-gear starter motor ensures reliable cranking under cold or high-resistance conditions. Optional PTO drives, hydraulic pump mounts, air compressors, and additional accessory drive configurations support diverse industrial applications. Crankcase ventilation components control crankcase pressure and reduce oil vapor emissions.
| Dimensions and Weight |
Physical dimensions include 1400–1700 mm (55.1–66.9 inches) in length, 850–1000 mm (33.5–39.4 inches) in width, and 1150–1450 mm (45.3–57.1 inches) in height. Dry weight typically ranges from 900 to 1200 kg (1984–2645 lbs) depending on accessory choice, turbocharger configuration, cooling layout, and generator mounting.
| Maintenance Data |
Routine maintenance is essential for reliable heavy-duty operation. Oil and filter changes are recommended every 250–300 hours. Fuel filters must be replaced every 250–400 hours depending on fuel quality. Air filter replacement varies from 100 to 300 hours depending on environment. Valve lash should be checked every 500–600 hours.
Coolant replacement is recommended every two years or 2000 hours. Injector servicing including cleaning, spray-pattern testing, and pump timing verification typically occurs every 1500–2000 hours. Compression testing every 3000 hours helps assess internal wear. Routine inspections of belts, hoses, turbo lubrication lines, crankcase ventilation components, and coolant hoses are vital for long-term uptime.
| Tightening Torques |
Cylinder head bolts: 200–230 Nm (148–170 lb-ft)
Main bearing cap bolts: 160–200 Nm (118–148 lb-ft)
Connecting rod bolts: 80–100 Nm (59–74 lb-ft)
Flywheel bolts: 260–300 Nm (192–221 lb-ft)
Crankshaft pulley bolt: 280–320 Nm (207–236 lb-ft)
Injector hold-down bolts: 25–30 Nm (18–22 lb-ft)
Glow plugs or intake heaters: 10–15 Nm (7–11 lb-ft)
Oil drain plug: 40–50 Nm (30–37 lb-ft).
| Vehicle Applications |
The Cummins 6LTAA9.5-G1 is widely used in heavy-duty generator sets, agricultural machines, wheel loaders, excavators, drilling rigs, mining equipment, rock crushers, large compressors, and marine auxiliary systems. Its combination of high displacement, mechanical simplicity, robust torque curve, and stable continuous-duty characteristics make it a reliable power solution across multiple global industries.
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