Cummins 6BT5.9-G1 Specifications
| Engine Model: Cummins 6BT5.9-G1 |
| Engine Type: 4-cycle inline 6-cylinder direct injection liquid-cooled diesel |
| Total Displacement: 359 cu.in (5.9 L) |
| Rated Engine Power: 161-221 Hp (120-165 kW) at 1800 rpm |
| Aspiration Type: Turbocharged |
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The Cummins 6BT5.9-G1 is one of the most widely
used mid-range industrial diesel engines in the world. Belonging to the
Cummins B-Series engine family, the 6BT5.9-G1 is known for exceptional
reliability, simple mechanical design, low operating cost, and robust
performance in harsh industrial environments. This naturally aspirated
or turbocharged 5.9-liter inline-six powerplant is extremely popular in
generator sets, construction equipment, agricultural machinery, marine
auxiliary equipment, pumps, and commercial vehicles.
The 6BT’s heavy-duty cast-iron construction, mechanical direct-injection
fuel system, and durable rotating assembly make it capable of long
service intervals and extended overhaul life. The 6BT5.9-G1 in generator
applications provides dependable continuous-duty power output with
excellent fuel economy, easy maintenance, and world-class durability.
The Cummins 6BT5.9-G1 is a four-stroke, water-cooled, inline
six-cylinder diesel engine. Displacement is approximately 5.9 liters
(359 cubic inches). Bore measures 102 mm (4.02 in) and stroke is 120 mm
(4.72 in). The long-stroke layout delivers strong low-end torque and
fuel-efficient operation.
Power ratings for G1 generator-drive
configuration:
– Standby: 132 kW (177 hp) at 1,500 rpm or 165 kW (221 hp) at 1,800 rpm
– Prime: 120 kW (161 hp) at 1,500 rpm or 150 kW (201 hp) at 1,800 rpm
Peak torque: Approximately 650–800 Nm (479–590 lb-ft) depending on fuel
curve. Compression ratio is approximately 17.5:1 depending on
configuration. Idle speed is typically around 700–800 rpm. Firing order:
1-5-3-6-2-4.
Governed speed:
– 1,500 rpm (50 Hz)
– 1,800 rpm (60 Hz)
The crankshaft is forged steel with seven main bearings. Pistons are
cast aluminum with reinforced crowns and cooling oil galleries.
Connecting rods are forged steel with replaceable bearings. The camshaft
is gear-driven for long-term timing stability.
The engine block is high-strength cast iron with deep stiffening ribs
and robust main bearing saddles. The cylinders are parent-bore type,
machined directly into the block. The water jacket fully surrounds the
cylinders to ensure uniform heat dissipation and reduce thermal
distortion.
The cast-iron cylinder head includes:
– Two intake and two exhaust valves per cylinder
– Direct-injection combustion chambers
– Hardened valve seats
Valve-lash specifications (cold):
– Intake: 0.254 mm (0.010 in)
– Exhaust: 0.508 mm (0.020 in).
The 6BT5.9-G1 utilizes a mechanical direct-injection fuel system
featuring:
– Mechanical lift pump
– Bosch-style inline mechanical fuel-injection pump
– Multi-hole mechanical injectors
– High-efficiency filtration with primary and secondary elements
Injection pressure typically ranges from 250 to 400 bar depending on
pump settings.
Fuel-system maintenance:
– Replace filters every 250–300 hours
– Drain water separator as needed
– Injector service every 1,000–1,500 hours
– Pump timing checks at overhaul intervals.
A full-pressure wet-sump lubrication system is used.
Oil capacity: 13–16 liters (13.7–16.9 qt)
Oil pressure:
– 275–380 kPa (40–55 psi) operating
– 70–100 kPa (10–15 psi) idle
Recommended oil: SAE 15W-40 diesel oils meeting API CI-4, CJ-4, or CK-4
Oil-change interval: approx. 250 hours for generator applications.
The engine uses a belt-driven centrifugal water pump that circulates
coolant through the block, head, and radiator.
Thermostat:
– Opening: 82°C (180°F)
– Full open: 95°C (203°F)
Cooling-system capacity: 20–25 liters (21–26 qt)
System pressure: 70–100 kPa (10–15 psi).
| Intake and Exhaust Systems |
Intake options include:
– Dry-type air filters
– Dual-stage heavy-duty filtration
– Optional pre-cleaners
Turbocharged versions (6BT5.9) include a fixed-geometry turbocharger
with pressure-lubricated bearings. Aftercooling may be optional
depending on configuration.
Exhaust manifolds are cast iron, designed for long-term thermal cycling.
| Electrical and Starting Systems |
Standard electrical configurations:
– 12V or 24V starting system
– Alternator: 35–70 amps
– Sensors: oil pressure, coolant temperature, speed/tachometer
There is no ECM; the engine is fully mechanical in the G1 configuration.
Depending on configuration, the 6BT5.9-G1
supports:
– PTO drives
– Hydraulic pump connections
– Generator heads
– Remote radiators
– Belt-driven auxiliaries.
Approximate physical dimensions:
– Length: 1,050–1,150 mm (41–45 in)
– Width: 700–800 mm (28–31 in)
– Height: 1,000–1,150 mm (39–45 in)
Dry weight: 430–500 kg (948–1,102 lb).
– Oil and filter: every 250 hr
– Fuel filters: 250–300 hr
– Air filter: inspect every 50–100 hr
– Valve adjustment: every 1,000 hr
– Injector service: every 1,000–1,500 hr
– Coolant replacement: every 2 years
– Compression test: every 2,000 hr.
– Cylinder-head bolts: 190–210 Nm (140–155 lb-ft) + angle torque
– Main-bearing caps: 245–260 Nm (181–192 lb-ft)
– Connecting-rod bolts: 75–85 Nm (55–63 lb-ft)
– Flywheel bolts: 135–150 Nm (100–111 lb-ft)
– Crankshaft damper bolt: 270–300 Nm (199–221 lb-ft)
– Oil drain plug: 40–50 Nm (30–37 lb-ft)
– Injector hold-down: 25–30 Nm (18–22 lb-ft).
The Cummins 6BT5.9-G1 engine is widely used
in:
– Generator sets (120–165 kW class)
– Agricultural tractors
– Wheel loaders
– Telehandlers
– Forklifts
– Medium-duty trucks
– Marine auxiliary power
– Pumps and compressors
– Irrigation systems.
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