Yanmar TF120M Specifications
| Engine Model: Yanmar TF120M |
| Engine Type: 4-stroke 1-cylinder horizontal water-cooled diesel |
| Total Displacement: 38.9 cu.in (0.64 L) |
| Rated Engine Power: 12 Hp (8.8 kW) at 2400 rpm |
| Fuel System Type: Direct injection |
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The Yanmar TF120M is a horizontal,
single-cylinder, water-cooled diesel engine belonging to the TF series,
which was developed for heavy-duty industrial and agricultural tasks.
The "M" designation specifically indicates the radiator-cooled version,
as opposed to the "H" hopper-cooled variant, making this engine suitable
for continuous operation in various environments including construction
sites, agricultural machinery, and generator sets.
This engine features a direct injection combustion system for high
thermal efficiency and incorporates a dual-shaft balancer system to
reduce vibration, a characteristic uncommon in single-cylinder engines
of its class. The Yanmar TF120M is recognized for its robust
construction, low oil consumption, and ease of maintenance, serving as a
power source for water pumps, compact tractors, rice transplanters, and
auxiliary generators.
The Yanmar TF120M is a single-cylinder diesel engine operating on the
four-stroke cycle. Its horizontal orientation provides a low profile,
which is advantageous for mounting in confined machinery compartments.
The direct injection system distinguishes this engine from indirect
injection designs, offering improved fuel efficiency and easier cold
starting.
Engine Type: Horizontal, 1-cylinder, 4-stroke, water-cooled diesel.
Displacement: 0.638 L / 38.9 cu.in.
Bore x Stroke: 92.0 mm x 96.0 mm / 3.62 in x 3.78 in.
Compression Ratio: 17.7:1.
Combustion System: Direct injection.
Maximum Rated Output: 8.8 kW / 12.0 hp at 2,400 rpm.
Continuous Output: 7.7 kW / 10.5 hp at 2,400 rpm.
Starting System: Manual hand-crank standard; electric starter optional.
Cooling System: Liquid-cooled with radiator and forced circulation.
Lubricating System: Fully sealed forced lubrication with trochoid pump
and hydraulic regulator valve.
Lubricating Oil Capacity: 2.8 L / 3.0 US qt.
Fuel Tank Capacity: 11.0-11.9 L / 2.9-3.1 US gal.
Fuel Consumption: 2.8 L/h / 0.74 GPH at rated output.
The cylinder block is constructed from high-grade cast iron using an
open-deck design. This material was selected for its durability and
resistance to thermal distortion under continuous heavy loads. The
cylinder bore is machined with a precision-honed surface.
The horizontal orientation of the block allows gravity-assisted oil
return to the sump and provides a low center of gravity for the
machinery it powers. The crankcase is integrated into the block casting.
The engine utilizes a dual-shaft balancer system located within the
block to counteract the primary and secondary vibration inherent to
single-cylinder operation.
The cylinder head is manufactured from cast iron and designed with a
direct injection configuration. The valve mechanism is driven by a
camshaft located in the crankcase, utilizing pushrods and rocker arms to
actuate the valves.
Valve Configuration: Overhead valve (OHV), 2 valves per cylinder.
Valve Clearance: Requires periodic manual adjustment.
Injection Nozzle: Hole-valve type positioned centrally in the cylinder
head for direct injection into the combustion bowl.
The TF120M employs a direct injection system with a high-pressure
Bosch-type in-line injection pump. A mechanical governor regulates fuel
delivery based on engine speed to prevent overspeeding under varying
loads. High-pressure steel line delivers fuel to the hole-valve type
injection nozzle seated in the cylinder head.
The system is designed for complete combustion and low fuel consumption
across the operating range from idle to 2,400 rpm. The fuel lift pump is
a diaphragm type mounted directly on the injection pump body.
Lubrication is provided by a fully sealed forced feed system using a
trochoid gear pump. The pump draws oil from the sump and forces it
through a full-flow filter before distributing it to the crankshaft,
connecting rod bearing, camshaft, and rocker arm assembly.
A hydraulic regulator valve maintains consistent oil pressure across the
operating speed range. The oil pan is a stamped steel unit with a
capacity of 2.8 liters, sufficient for extended service intervals in
dusty agricultural or construction environments.
The cooling system is a pressurized, forced circulation design utilizing
a belt-driven centrifugal water pump. Coolant is circulated through the
cast iron block and cylinder head to a tube-and-fin radiator. A
thermosiphon or thermostat-controlled system maintains optimal operating
temperature.
A cooling fan is mounted on the flywheel side or driven by the water
pump pulley, directing airflow across the radiator core. The radiator
system distinguishes the "M" version from the "H" version, allowing the
engine to operate continuously without external water supply.
Intake System: The intake system incorporates a heavy-duty air cleaner
with a cyclone pre-filter and paper element, designed for high-dust
environments.
Timing System: The camshaft and injection pump are driven by a gear
train from the crankshaft. This gear-driven system eliminates belt or
chain replacement intervals.
Exhaust System: A large-capacity muffler is fitted to reduce exhaust
noise emitted during operation.
Vibration Control: A dual-shaft balancer system rotates at twice the
crankshaft speed to cancel the secondary vibration forces inherent to
single-cylinder engines, resulting in reduced operator fatigue and
extended component life.
Overall Length: 689-695 mm / 27.1-27.4 in
Overall Width: 348-352 mm / 13.7-13.9 in
Overall Height: 530 mm / 20.9 in
Dry Weight (engine only): 101-106.5 kg / 223-235 lbs
Dry Weight (with generator end): 180-243 kg / 397-536 lbs
Engine Oil: Use 15W-40 or 10W-30 diesel oil meeting API CD/CF or higher.
Engine Oil and Filter: Replace every 150-200 operating hours or
annually.
Fuel Filter: Replace every 200 hours or sooner if water is detected in
the sediment bowl.
Air Cleaner Element: Clean the cyclone pre-filter daily in dusty
environments.
Air Cleaner Element: Replace paper element every 200-300 hours.
Valve Clearance: Inspect and adjust every 300-500 hours.
Cooling System: Check coolant level daily.
Cooling System: Replace coolant every 1,000 hours or 2 years.
Injection Timing: Check by a diesel specialist if hard starting or
excessive smoke occurs.
Cylinder Head Bolts: 30-36 lb-ft / 40-50 Nm
Connecting Rod Cap Bolts: 29-33 lb-ft / 40-45 Nm
Main Bearing Cap Bolts: 51-58 lb-ft / 70-80 Nm
Flywheel Bolts: 44-51 lb-ft / 60-70 Nm
Injector Hold-Down Nuts: 18-22 lb-ft / 25-30 Nm
Rocker Arm Shaft Brackets: 18-22 lb-ft / 25-30 Nm
Crankshaft Pulley Nut: 87-101 lb-ft / 120-140 Nm
The TF120M engine is utilized across multiple industrial, agricultural,
and power generation platforms globally.
Yanmar YTG Series Generators: Models YTG9.0T (3-phase, 9 kVA) and YTG10S
(single-phase, 10 kVA) are powered by the TF120M.
Water Pumps: High-lift and high-volume dewatering pumps.
Agricultural Machinery: Compact tractors, rice transplanters, and
two-wheel tractors (power tillers).
Construction Equipment: Small vibratory rollers and compactors.
Research Applications: The engine serves as a test platform for
alternative fuels, including waste plastic disposal fuel (WPDF) and
biodiesel blends.
Marine Auxiliary: Small workboats and fishing craft auxiliary power.
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