Yanmar 4D84E Specifications
| Engine Model: Yanmar 4D84E |
| Engine Type: 4-stroke inline 4-cylinder naturally aspirated water cooled diesel |
| Total Displacement: 121.7 cu.in (1.99 L) |
| Rated Engine Power: 40.4 Hp (30.1 kW) at 3000 rpm |
| Fuel System Type: Indirect injection |
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The Yanmar 4D84E is a 4-cylinder, naturally
aspirated industrial diesel engine from Yanmar's TN series. Produced
throughout the 1990s and 2000s, this powerplant became a cornerstone of
compact construction equipment, powering Komatsu mini-excavators, skid
steer loaders, and various generator sets. The 4D84E is a vertical,
water-cooled, 4-cycle diesel engine utilizing indirect injection (IDI)
technology, which provides smooth operation and high torque at low
engine speeds - a critical requirement for hydraulic machinery.
The engine shares its fundamental architecture with the Yanmar 4TNE84
industrial engine, a relationship confirmed by cross-compatibility of
major components such as the crankshaft and pistons. The Yanmar 4D84E
employs a cast iron cylinder block and cylinder head, a combination that
provides exceptional rigidity and resistance to thermal distortion under
continuous load. The bore and stroke dimensions are 84.0 mm x 90.0 mm, a
long-stroke configuration that prioritizes torque production over peak
power output.
The engine is mechanically governed and utilizes a Bosch-type in-line
injection pump or distributor pump, depending on the specific
application and serial number range. Lubrication is provided by a
forced-feed trochoid pump with a full-flow spin-on filter. The cooling
system is pressurized, featuring a centrifugal water pump driven by the
engine's accessory drive belt. The Yanmar 4D84E gained a reputation for
reliability in demanding environments, powering equipment from Komatsu,
Kobelco, Doosan, and Mustang, as well as Yanmar-branded generators. Its
application in Komatsu PC40 and PC45 series excavators remains the most
common installation.
The engine operates on a four-stroke indirect injection diesel cycle
with a naturally aspirated induction method. It is configured for
vertical installation in industrial equipment, skid steer loaders,
excavators, and generator sets. Engine speed is regulated by a
mechanical centrifugal governor integrated into the injection pump.
Engine Type: Vertical inline-4, water-cooled, 4-stroke diesel, indirect
injection
Displacement: 1.995 liters (121.7 cu.in)
Bore x Stroke: 84.0 mm x 90.0 mm (3.31 in x 3.54 in)
Compression Ratio: 18.5:1 to 19.0:1
Firing Order: 1-3-4-2 (standard inline-4 firing sequence)
Idle Speed (Low): 750 - 850 rpm
Idle Speed (High): 2,500 - 3,000 rpm, dependent on governor setting
Maximum Power (Intermittent): 28.3 - 30.1 kW (38.4 - 40.4 hp)
Maximum Torque (Rated Load): 140 Nm (103 lb-ft) at 1,800 rpm
Direction of Rotation: Counter-clockwise when viewed from the flywheel
side
The cylinder block is constructed from cast iron with a closed-deck
design, providing structural rigidity for sustained high-load operation
in construction equipment. The block incorporates five main bearings
supporting the crankshaft. The deep-skirt design extends below the
crankshaft centerline, enhancing rigidity and reducing noise
transmission. Dimensions of the cylinder block are approximately 406 mm
(16.0 in) in length, 337 mm (13.3 in) in width, and 304 mm (12.0 in) in
height.
Cylinder Bore Diameter: 84.0 mm (3.31 in)
Main Bearing Journal Diameter: 65.0 mm (2.56 in)
Piston Material: High-temperature aluminum alloy
Piston Pin Diameter: 26.0 mm (1.02 in)
Compression Ring Height: 2.0 mm - 2.0 mm - 4.0 mm (top, second, oil
ring)
Crankshaft: Forged carbon steel, fully counter-weighted
Connecting Rods: Forged steel with fracture-split cap design
Cylinder Block Construction: Cast iron with cast-in cylinder liners
The cylinder head is manufactured from cast iron and mounts directly to
the cylinder block using conventional head gasket technology. The
casting is 406 mm (16.0 in) in length and 144 mm (5.7 in) in height. The
overhead valve (OHV) layout uses pushrods actuated by a camshaft located
within the cylinder block.
The indirect injection system utilizes a swirl-type pre-combustion
chamber cast into the cylinder head for each cylinder, promoting
complete combustion and reducing combustion noise. Valvetrain: OHV
(Overhead Valve), gear-driven camshaft located in the cylinder block, 8
valves total (2 valves per cylinder: intake and exhaust)
Intake Valve Diameter: 34.0 mm (1.34 in)
Exhaust Valve Diameter: 30.0 mm (1.18 in)
Valve Seat Material: High-strength sintered alloy
Valve Clearance (cold): Intake: 0.20 mm (0.008 in), Exhaust: 0.20 mm
(0.008 in)
Pre-Combustion Chamber: Swirl-type, removable
The fuel system utilizes an indirect injection (IDI) configuration with
a Bosch-type in-line injection pump or distributor pump, dependent on
the application and serial number. The injection pump is mechanically
governed, providing automatic speed control in response to load changes.
Fuel is delivered to pintle-type injectors mounted in the pre-combustion
chambers.
Fuel Injectors: Pintle-type valves, injection pressure 12.0 - 13.0 MPa
(1,740 - 1,885 psi)
Injection Pump: Bosch-type in-line (individual plungers) or distributor
pump
Injection Timing: 14 - 16 deg before top dead center (crankshaft),
adjustable via shims
Fuel Filter: Spin-on cartridge type with integral water separator
Fuel Requirement: Diesel fuel meeting minimum cetane rating of 45
The lubrication system is a fully pressurized wet-sump design utilizing
a trochoid gear pump driven by the crankshaft. The system incorporates a
full-flow spin-on cartridge oil filter. The pump delivers 5 to 7 liters
of oil per minute during operation at rated speed.
Oil Pump Type: Trochoid gear pump
Oil Viscosity: 10W-30, 15W-40, or SAE 30 depending on ambient
temperature
Oil Capacity (with filter change): 5.5 - 7.0 liters (5.8 - 7.4 qt)
Oil Filter Type: Spin-on cartridge, full-flow design
Oil Pressure (at rated speed, warm): 180 - 800 kPa (26 - 116 psi)
Oil Pan Material: Stamped steel or fabricated steel,
application-specific
Oil Cooler: Plate-type oil-to-water heat exchanger (optional, equipment
dependent)
The cooling system is a pressurized design utilizing a centrifugal water
pump driven by the engine’s accessory drive belt. A wax-type thermostat
regulates coolant flow. The radiator is equipment-specific and not
considered part of the long block assembly.
Coolant Type: Ethylene-glycol based antifreeze with corrosion inhibitors
Coolant Capacity (engine only): 3.5 - 4.0 liters (3.7 - 4.2 qt)
Water Pump Type: Centrifugal, max flow 67.1 L/min, max pressure 1.2 MPa
Thermostat Opening Temperature: 71 - 82 °C (160 - 180 °F),
application-specific
Radiator Cap Pressure: 70 - 100 kPa (10 - 15 psi)
Camshaft Drive: Helical gear train driven directly from the crankshaft
gear, located at the flywheel end of the engine.
Starting System: 12V electric starter (1.4 kW or 2.0 kW depending on
application). Charging System: 12V alternator, output 35A minimum.
Glow Plug System: Glow plugs are installed in the pre-combustion
chambers, controlled by a glow timer relay with automatic post-heating
cycles.
Governor: Mechanical centrifugal governor integrated into the injection
pump, providing all-speed regulation.
Emission Control System: Basic crankcase ventilation system; no EGR or
DPF on naturally aspirated 4D84E variants.
Overall Length: 680 mm (26.8 in)
Overall Width: 550 mm (21.7 in)
Overall Height: 660 mm (26.0 in)
Dry Weight (complete engine, long block): 185 kg (408 lb)
Intake Valve Clearance (cold): 0.20 mm (0.008 in).
Exhaust Valve Clearance (cold): 0.20 mm (0.008 in).
Valve Clearance Inspection interval: 500 hours.
Injection Timing: 14 - 16 degrees BTDC. Check every 1,000 hours.
Engine Oil Change Interval: 250 hours or 6 months (mineral oil).
Engine Oil Change Interval: 500 hours or 12 months (synthetic oil).
Engine Oil Filter Replacement: Every oil change.
Fuel Filter Replacement: Every 500 hours or annually.
Air Filter Element: Replace every 500 hours.
Coolant Replacement: Every 2,000 hours or 2 years.
Glow Plug Inspection: Check resistance and operation every 1,000 hours.
Cylinder Head Bolts: 80 - 90 Nm (59 - 66 lb-ft)
Main Bearing Cap Bolts: 90 Nm (66 lb-ft)
Connecting Rod Cap Nuts: 45 Nm (33 lb-ft)
Rocker Arm Shaft Bracket Bolts: 25 Nm (18 lb-ft)
Intake Manifold Nuts: 20 Nm (15 lb-ft)
Exhaust Manifold Nuts: 25 Nm (18 lb-ft)
Injection Nozzle Holders: 70 Nm (52 lb-ft)
Glow Plugs: 15 Nm (11 lb-ft)
Oil Pan Bolts: 12 Nm (9 lb-ft)
Valve Cover Bolts: 10 Nm (7 lb-ft)
Crankshaft Pulley Nut: 200 Nm (148 lb-ft)
Flywheel Bolts: 80 Nm (59 lb-ft)
The Yanmar 4D84E engine was widely utilized across compact construction
equipment and power generation applications. The engine is frequently
marketed under both the Yanmar (4TNE84) and Komatsu (4D84E)
designations, with complete parts interchangeability.
Excavators:
Komatsu PC40-7, PC40R-8, PC45R-8, PC45-1, PC40MRX-1-E.
Kobelco SK40SR-2: Installed in this compact excavator model.
Skid Steer Loaders:
Komatsu SK510, SK815, SK820, SK820-5.
Doosan 1340XL / Mustang 2040, 2042, 2044, 2050.
Power Generation:
Yanmar YEG400DSHC, YEG400DSHS, YEG400DTHC, YEG400DTHS.
Kohler 15CCO, 15CCFO, 15R091, 15ROY, 15ROZ.
Other Equipment:
Ariens Gravely PRO CHIP 944: Wood chipper application.
Komatsu BC70 Drill Machine: Rock drilling equipment.
Komatsu RAM700-3 Backhoe: Tractor-loader-backhoe.
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