John Deere 6068HF120 Specifications
| Engine Model: John Deere 6068HF120 |
| Engine Type: 4-cycle inline 6-cylinder turbocharged liquid-cooled diesel |
| Total Displacement: 415 cu.in (6.8 L) |
| Rated Engine Power: 188-245 Hp (140-183 kW) at 1800 rpm |
| Fuel System Type: Direct fuel injection |
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The John Deere 6068HF120 is a 6.8-liter,
six-cylinder, turbocharged and aftercooled diesel engine designed
specifically for demanding power generation applications. This
four-stroke, direct injection engine belongs to John Deere's Heavy Fuel
(HF) series, engineered to operate reliably on a wider range of
distillate fuels, including lower cetane and higher viscosity diesel
fuels, while maintaining performance and durability.
The engine employs a robust mechanical governing system (MECA) for
precise speed control essential for generator set frequency stability.
Its construction integrates heavy-duty components, including a
high-strength cylinder block with wet liners, a four-valve cylinder
head, and a high-capacity cooling system. The 6068HF120 is optimized for
continuous operation in prime power and standby generator roles,
offering high power density and fuel flexibility for data centers,
industrial facilities, and commercial installations.
Engine Type: 6-cylinder, inline, 4-stroke cycle, vertical,
liquid-cooled, turbocharged and aftercooled diesel.
Combustion System: Direct injection, four-valve.
Aspiration: Turbocharged with air-to-air aftercooler (charge-air
cooler).
Rotation: Counterclockwise when viewed from the flywheel end.
Firing Order: 1-5-3-6-2-4.
Bore: 106.0 mm (4.17 inches).
Stroke: 127.0 mm (5.00 inches).
Displacement: 6.8 liters (415 cubic inches).
Compression Ratio: 17.0:1.
Governor Type: Mechanical, isochronous (MECA - Mechanical Electronic
Control Actuator).
Standby Power Rating: 155 to 183 kW (208 to 245 Hp) at 1800 crankshaft
rpm (60 Hz) or 1500 rpm (50 Hz).
Prime Power Rating: 140 to 166 kW (188 to 223 Hp) at 1800 crankshaft rpm
(60 Hz) or 1500 rpm (50 Hz). High Idle Speed: Governed by MECA system.
Low Idle Speed: Not applicable for generator set constant-speed
operation.
Fuel Shutoff: Mechanical or electric solenoid.
Dry Weight (Base engine): 568 kg (1252 lbs).
Overall Length (Front of fan to flywheel housing face): 1141 mm (44.9
inches).
Overall Width (Maximum): 623 mm (24.5 inches).
Overall Height (Top of valve cover to base rail): 1009 mm (39.7 inches).
The cylinder block is a single-piece, high-strength gray iron casting
with a deep-skirt design. This design provides maximum rigidity to
handle high combustion pressures and maintain precise alignment of
rotating components under continuous load. The block incorporates
replaceable, press-fit wet-type cylinder sleeves. These sleeves are
manufactured from centrifugally cast alloy iron, formulated for wear
resistance and compatibility with a broader spectrum of fuel sulfur
contents.
The crankshaft is supported by seven main bearings with steel-backed,
aluminum alloy bearing inserts. Main bearing caps are nodular iron and
are secured with two vertical bolts each, supplemented by two lateral
cross-bolts per cap. This cross-bolted main bearing cap system creates
an exceptionally rigid lower block structure, crucial for minimizing
crankshaft deflection in heavy-fuel, high-output operation.
The cylinder head is a single-piece, cast iron component. It employs a
crossflow design with four valves per cylinder (two intake, two
exhaust). This four-valve layout maximizes airflow efficiency, promoting
complete combustion which is critical for heavy fuel operation and
emissions control. Valve seats are induction-hardened inserts capable of
withstanding aggressive fuel compositions.
Valve guides are replaceable. Intake and exhaust valves are manufactured
from specialized heat-resistant steel alloys. Valve actuation uses
individual, shaft-mounted rocker arms. Valve lash is adjusted manually
via screw-type adjusters on the rocker arms, allowing for precise
maintenance. The camshaft, located centrally in the cylinder block,
operates the valves through solid lifters and pushrods. A multilayer
steel head gasket provides a robust seal for high combustion pressures.
The fuel system is a direct injection, pump-line-nozzle configuration
engineered for heavy fuel operation. It incorporates a fuel priming and
transfer pump module. Fuel passes through a primary filter/water
separator and a secondary fuel filter specifically designed for fine
filtration. The injection pump is an in-line, plunger-type unit (John
Deere or Bosch) with a mechanical MECA governor mounted integrally.
The MECA governor provides isochronous speed control, maintaining a
constant engine speed regardless of load changes, which is mandatory for
stable generator frequency. The system includes a fuel heater to
maintain optimal viscosity, especially important for higher viscosity
distillates. High-pressure steel lines connect the pump to each
injector. The injectors are multi-hole, pencil-type units with materials
selected for heavy fuel service. A solenoid-operated fuel shutoff valve
is standard.
The lubrication system is a full-pressure, gear-driven design with
enhanced capacity for continuous duty. A gear-type oil pump, driven from
the front gear train, draws oil from the oil pan through a pickup tube
and screen. Pressurized oil is directed through a full-flow, spin-on oil
filter. A bypass oil cooler is integrated into the system to maintain
optimal oil temperature under sustained load.
Filtered and cooled oil is distributed via main galleries to the
crankshaft main bearings, connecting rod bearings, camshaft bearings,
and the valve rocker shaft. A piston cooling jet sprays oil onto the
underside of each piston crown. The turbocharger center bearing receives
oil via a dedicated feed line. Total engine oil system capacity is 31.5
liters (8.3 U.S. gallons). Oil meeting John Deere performance standard
JDM J27 for heavy-duty diesel service is required.
The cooling system is a high-capacity, pressurized, liquid-cooled
design. A centrifugal water pump, gear-driven from the front of the
engine, circulates coolant. Coolant flow is directed through the
cylinder block, cylinder head, oil cooler, and aftercooler core. A
wax-pellet-type thermostat regulates coolant temperature. System
pressure is maintained by a radiator pressure cap, rated for 100 kPa (15
psi).
The system includes a belt-driven fan integrated into the packaged
genset radiator assembly. The radiator is sized for ambient conditions
up to 50 C (122 F). The engine jacket coolant capacity is 25.8 liters
(6.8 U.S. gallons). A 50/50 mixture of ethylene-glycol antifreeze
meeting John Deere specification JDM J71C and demineralized water is
required to prevent corrosion and scaling.
Air Management System: The system includes a wastegated turbocharger and
an air-to-air aftercooler. The aftercooler significantly reduces the
temperature of the compressed intake air, increasing its density for
optimal combustion efficiency and power output under all ambient
conditions.
Electrical System: The engine employs a 12V or 24V electric starting
system with a high-torque starter motor. A 12V or 24V alternator
provides charging current for the engine battery system. An intake air
heater grid assists in cold-weather starting. The MECA governor includes
an electric actuator for precise fuel rack positioning.
Exhaust System: Exhaust gases drive the turbocharger turbine before
exiting through an insulated exhaust manifold and elbow. Mounting
System: The engine is configured with a generator set base frame
incorporating vibration isolators. The SAE flywheel housing is designed
for direct coupling to a wide range of alternators.
Overall Length (Front of fan to flywheel housing face): 1141 mm (44.9
inches).
Overall Width (Maximum at mounting rails): 623 mm (24.5 inches).
Overall Height (Top of valve cover to base of mounting rails): 1009 mm
(39.7 inches).
Dry Weight (Engine as packaged for genset duty, less coolant and oil):
568 kg (1252 lbs).
Engine Oil Change Interval: 500 service hours for standard diesel fuel.
Intervals may be reduced to 250 hours when operating on heavy fuel oils
(HFO) or under severe conditions. Oil Filter Change: Replace with every
oil change.
Fuel Filter Service: Drain water from primary separator daily; replace
primary and secondary filter cartridges every 500 service hours. Air
Filter Element Service: Replace element based on restriction gauge
indication; inspect housing every 250 service hours.
Coolant Change Interval: 3000 service hours or 3 years, whichever occurs
first. Valve Lash Adjustment (Cold Engine Setting): Intake valve: 0.35
mm (0.014 inches); Exhaust valve: 0.46 mm (0.018 inches). Inspect and
adjust every 1000 service hours.
Fuel Injection Pump Timing: Verify and set per factory specification
during major service; inspection recommended every 2000 service hours.
Aftercooler Core Service: Inspect and clean the external fins of the
aftercooler core every 1000 service hours. MECA Governor Adjustment:
Requires specialized tools and procedures; perform per manufacturer's
schedule.
Cylinder Head Bolts: Torque in specified sequence to 160 Nm (118 lb-ft),
then final angle tighten an additional 90 deg.
Main Bearing Cap Bolts (Vertical): 190 Nm (140 lb-ft). Main bearing cap
cross-bolts: 100 Nm (74 lb-ft).
Connecting Rod Cap Nuts: 115 Nm (85 lb-ft), then final tighten an
additional 60-degree turn.
Flywheel to Crankshaft Bolts: 160 Nm (118 lb-ft).
Rocker Arm Shaft Support Bolts: 55 Nm (41 lb-ft).
Injector Clamp Bolt: 35 Nm (26 lb-ft).
Oil Pan Bolts: 24 Nm (18 lb-ft).
Turbocharger Mounting Nuts: 35 Nm (26 lb-ft).
The John Deere 6068HF120 engine is designed exclusively for stationary
power generation applications. It is not intended for mobile equipment.
Its primary application is as the prime mover in diesel generator sets
for both standby (emergency) and prime (continuous) power. These
generator sets are deployed in facilities requiring reliable off-grid or
backup power, including data centers, telecommunications hubs,
hospitals, water treatment plants, industrial manufacturing facilities,
and large commercial buildings.
The engine's heavy fuel capability makes it suitable for installations
in regions where fuel quality is variable or where cost savings from
using heavier distillates are significant. The engine is commonly
integrated into generator packages by John Deere Electric Power and
other major genset original equipment manufacturers for global
distribution.
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