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Cummins 6LTAA9.5-G1 Engine

The Cummins 6LTAA9.5-G1 is a heavy-duty, 9.5-liter, in-line 6-cylinder, 4-stroke industrial G-drive diesel engine. Evolved from the smaller C8.3 and L8.9 series architectures, this unit is highly optimized for stationary power generation and continuous operation under demanding thermal loads. It is constructed using an integrated block design featuring cast internal fluid circuits, which replaces traditional external hosing assemblies to eliminate prospective coolant and oil leak paths. To sustain high structural rigidity, the engine utilizes wet cylinder liners equipped with an intermediate midpoint stop to control liner geometry and prevent distortion under heavy loads. It utilizes high-strength, two-piece articulated pistons comprised of a steel crown paired with a cast-aluminum skirt to distribute cyclic mechanical loading while reducing reciprocating inertia.

Total Valves: Outfitted with a high-flow 24-valve cylinder head (4 valves per cylinder). Valvetrain Layout: Traditional industrial Overhead Valve (OHV) design. Actuation System: Utilizes a single block-mounted bottom camshaft driving the overhead rocker arm assemblies via heavy-duty lifters and pushrods. Cylinder Bore: 116 mm (4.57 inches). Piston Stroke: 148 mm (5.83 inches). Total Displacement: Exactly 9.5 liters (580 cubic inches). Lubrication System: Internal gear-driven lubrication pump that circulates oil directly from the pan under pressure to the main bearings, camshaft, and overhead valve gear. Filtration and Cooling: Features an integrated full-flow oil filter assembly alongside a liquid-cooled oil cooler element that keeps oil viscosity stable by rejecting heat to the main jacket coolant.

Fuel Injection Pump: Outfitted with a premium mechanical inline injection pump (Bosch P7100 or BYC P-series pump) operating at high injection pressures to force cleaner combustion. Governor Control: Managed via an electronic or mechanical governor system to maintain precise regulation limits within 3% to 5% under load fluctuations. Delivery Method: Uses direct injection through centered vertical injectors, combined with a plateau-honed cross-cover liner structure to maximize thermal efficiency and reduce overall fuel consumption. Cooling System: Liquid-cooled jacket system utilizing a heavy-duty engine-driven water pump for continuous coolant circulation. Charge Air Cooling: The "AA" designation indicates an Air-to-Air Aftercooled (ATAAC) system. This uses a dedicated radiator network to cool compressed intake air before it reaches the combustion chamber, optimizing density and reducing emissions.

General Technical Data

Engine Specifications

Engine Model ............... Cummins 6LTAA9.5-G1
Engine Type ............... 4-cycle inline 6-cylinder direct injection turbocharged liquid-cooled diesel
Number of Cylinders ............... 6
Cylinder Arrangement ............... In-line
Engine Bore, in (mm) ............... 4.58 (116.0)
Engine Stroke, in (mm) ............... 5.82 (148.0)
Displacement, cu.in (L) ............... 580 (9.5)
Rated Engine Power, hp (kW) ............... 340-440 (255-330)
Rated Engine Speed, rpm ............... 1500-2200
Peak Torque ............... 1200-1600 Nm (885-1180 lb-ft) at 1300-1500 rpm
Idle Speed ............... 650-750 rpm
Aspiration Type ............... Turbocharged and aftercooled
Compression Ratio ............... 16.5:1-17.5:1
Firing Order ............... 1-5-3-6-2-4
Cylinder Block Type ............... Cast iron
Cylinder Head Type ............... Cast iron
Lubrication System ............... Full-pressure
Oil Pump Type ............... Gear-driven
Oil Filter Type ............... Full-flow, spin-on
Cooling System ............... Liquid-cooled
Water Pump Type ............... Belt-driven, centrifugal
Air Cleaner Type ............... Dry dual-stage
Starting System ............... Electric Starter
Electrical System ............... 12V or 24V
Alternator Rating, Amps ............... 50-120

Fuel System

Fuel System ............... Direct injection
Injection Pump Type ............... Rotary or inline
Fuel System Control ............... Mechanical
Governor Type ............... Mechanical
Fuel Injector Type ............... Multi-hole
Fuel Type ............... Diesel Fuel

Dimensions and Weight

Overall Length, in (mm) ............... 55.1-66.9 (1400-1700)
Overall Width, in (mm) ............... 33.5-39.4 (850-1000)
Overall Height, in (mm) ............... 45.3-57.1 (1150-1450)
Dry Weight, lbs (kg) ............... 1980-2530 (900-1150)

Maintenance Data

Service Information

Thermostat begins opening ............... 82C (180F)
Thermostat fully open ............... 95C (203F)
Cooling system pressure ............... 70-100 kPa (10-15 psi)
Operating oil pressure ............... 300-450 kPa (44-65 psi)
Idle oil pressure ............... 100-150 kPa (15-22 psi)
Intake Valve Clearance, in (mm) ............... 0.012 (0.30)
Exhaust Valve Clearance, in (mm) ............... 0.024 (0.61)

Engine Oil and Coolant

Engine Oil Type .................. SAE 10W-30, 15W-40
API Service Classifications ......................... CI-4, CJ-4, CK-4
Engine Oil Capacity, qts (L) .................. 23.1-29.4 (22.0-28.0)
Coolant Capacity, qts (L) ............... 31.5-42.0 (30.0-40.0)

Service Intervals

Change oil and filter ............... Every 250 hours
Replace fuel filters ............... Every 300 hours
Inspect air filter ............... Every 100 hours
Replace air filter ............... Every 300 hours
Change coolant ............... Every 2000 hours
Valve-lash adjustment ............... Every 1000 hours
Injector inspection ............... Every 1500-2000 hours
Compression test ............... Every 2500 hours
Drain water separator ............... As required
Belt inspection ............... As required

Service Specifications

Cylinder Bore Inside Diameter, in (mm) ............... 116.500-116.530 (4.5866-4.5878)
Crankshaft Journal Outside Diameter, in (mm) ............... 97.962-98.013 (3.8568-3.8588)
Crank Pin Outside Diameter, in (mm) ............... 75.962-76.013 (2.9906-2.9926)
Crankshaft End Play, in (mm) ............... 0.130-0.380 (0.0051-0.0150)
Intake Valve Stem Outside Diameter, in (mm) ............... 8.953-8.975 (0.3525-0.3533)
Exhaust Valve Stem Outside Diameter, in (mm) ............... 8.953-8.975 (0.3525-0.3533)
Intake Valve Guide Inside Diameter, in (mm) ............... 9.015-9.065 (0.3549-0.3569)
Exhaust Valve Guide Inside Diameter, in (mm) ............... 9.015-9.065 (0.3549-0.3569)
Intake Valve Stem to Guide Clearance, in (mm) ............... 0.040-0.112 (0.0016-0.0044)
Exhaust Valve Stem to Guide Clearance, in (mm) ............... 0.040-0.112 (0.0016-0.0044)
Intake Valve Spring Free Length, in (mm) ............... 59.40 (2.3386)
Exhaust Valve Spring Free Length, in (mm) ............... 59.40 (2.3386)
Intake Cam Height, in (mm) ............... 51.850-52.150 (2.0413-2.0531)
Exhaust Cam Height, in (mm) ............... 51.650-51.950 (2.0335-2.0453)
Piston Pin Outside Diameter, in (mm) ............... 44.993-45.005 (1.7714-1.7718)
Piston Pin to Piston Bore Clearance, in (mm) ............... 0.015-0.035 (0.0006-0.0014)
Second Ring Side Clearance, in (mm) ............... 0.070-0.110 (0.0028-0.0043)
Oil Ring Side Clearance, in (mm) ............... 0.050-0.090 (0.0020-0.0035)
Top Ring End Gap, in (mm) ............... 0.300-0.550 (0.0118-0.0217)
Second Ring End Gap, in (mm) ............... 0.400-0.650 (0.0157-0.0256)
Oil Ring End Gap, in (mm) ............... 0.250-0.500 (0.0098-0.0197)

Tightening Torque Specs

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)
Fuel line nuts ............... 25-30 Nm (18-22 lb-ft)
Water pump bolts ............... 25-30 Nm (18-22 lb-ft)
Oil drain plug ............... 40-50 Nm (30-37 lb-ft)

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• Cummins Engines Specs
  
• Cummins 6LTAA8.9-G2 Specs
  
• Cummins 6LTAA8.9-G3 Specs
  
• Cummins 6T-590 Specs
  
• Cummins 6T-830 Specs
  

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