Isuzu 3KC2 Specifications
| Engine Model: Isuzu 3KC2 |
| Engine Type: 4-stroke in-line 3-cylinder liquid-cooled diesel |
| Total Displacement: 59.8 cu.in (0.98 L) |
| Rated Engine Power: 40 Hp (29.8 kW) at 2500 rpm |
| Fuel System Type: Indirect injection |
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The Isuzu 3KC2 is a compact, naturally
aspirated, three-cylinder diesel engine from the Isuzu K series,
designed for industrial applications where reliability and simplicity
are paramount. The engine is widely utilized in mini excavators, small
generator sets, air compressors, and portable power generation units
across global markets. The 3KC2 represents an evolution within the K
series, incorporating updates aimed at improved longevity and structural
robustness compared to earlier variants such as the 3KC1.
Its design prioritizes straightforward serviceability with widely
available standard parts, contributing to reduced maintenance costs and
simplified field repairs. The engine employs an indirect injection fuel
system, a forced lubrication circuit, and a water-cooled cooling system
with a radiator and thermostat. Built with a cast iron block and an
overhead valve (OHV) configuration, the 3KC2 delivers consistent
performance in demanding environments including construction sites,
agricultural settings, and marine applications requiring saltwater
corrosion resistance.
The Isuzu 3KC2 is a 4-cycle, water-cooled, naturally aspirated, inline
3-cylinder diesel engine. It operates on the four-stroke principle with
an overhead valve (OHV) arrangement. The engine is characterized by its
compact dimensions and low weight, making it suitable for
space-constrained machinery.
Engine Type: 4-cycle, OHV water-cooled, naturally aspirated diesel.
Number of Cylinders: 3 inline.
Displacement: 980 cc (0.98 L, 59.8 cu.in).
Bore x Stroke: 74 mm x 76 mm (2.91 in x 2.99 in).
Compression Ratio: 17.0:1 (estimated based on K series).
Firing Order: 1-3-2.
Rated Power: 40 hp (29.8 kW) at 2500 rpm.
Idling Speed: 1100 rpm.
Fuel Type: Diesel fuel oil conforming to JIS K-2204 or equivalent
diesel.
Fuel Injection Timing: 16° BTDC (Before Top Dead Center).
Injection System: Indirect injection with a mechanical injection pump.
Aspiration: Naturally aspirated.
Rotation: Clockwise when viewed from the front of the engine.
The cylinder block is constructed from high-strength cast iron,
producing a rigid foundation for internal components. The block features
a deep-skirt design that extends below the crankshaft centerline,
providing enhanced support for the main bearing journals and reducing
noise, vibration, and harshness. Three cylinders are cast integrally
with the block.
The block is machined with mounting faces for the fuel injection pump on
the side, the water pump at the front, and the flywheel housing at the
rear. A pressed steel or cast aluminum oil pan is bolted to the lower
flange. The block incorporates a water jacket surrounding each cylinder
barrel to facilitate heat transfer to the circulating coolant. The
engine does not employ replaceable cylinder liners; the bores are
machined directly into the parent block material.
0The cylinder head is a single-piece, cast-iron cross-flow unit that
spans all three cylinders. The overhead valve (OHV) configuration places
the camshaft within the cylinder block, actuating the valves via
mechanical pushrods and rocker arms. Two valves per cylinder (one
intake, one exhaust) produce a total of six valves. Intake and exhaust
ports are located on opposite sides of the cylinder head. Valve seats
are pressed into the head and machined to precise angles.
Valve guides are press-fit. The valvetrain uses mechanical lash
adjusters (screw and locknut type), requiring periodic manual valve
clearance inspection and adjustment. The cylinder head gasket is a
composite construction with steel fire rings at each cylinder bore. Glow
plugs are installed in the cylinder head adjacent to each injector to
assist cold starting.
The fuel system is an indirect injection design. A mechanical
distributor-type injection pump (ND series or equivalent) is mounted to
the side of the cylinder block, driven by the engine gear train. The
pump incorporates an integral mechanical governor and a manual stop
control. A transfer pump within the injection pump draws fuel from the
tank through a primary fuel filter with a water separator.
High-pressure fuel lines route fuel from the injection pump to
pre-combustion chambers (swirl chambers) located in the cylinder head.
Three mechanical injectors, one per cylinder, inject fuel into the swirl
chamber where partial combustion occurs before flame propagates into the
main combustion chamber in the piston crown. The system operates without
electronic controls or sensors for fuel management. Compatibility with
high-sulfur diesel fuel is retained due to the absence of sensitive
common-rail components.
The lubrication system is a forced-feed, fully pressurized circuit. A
rotor-type oil pump, driven from the crankshaft nose, draws oil through
a strainer from a steel or aluminum sump. Oil passes through a spin-on
full-flow canister filter before distribution. The filter is a standard
C809J or equivalent element with dimensions 85 mm height, 65 mm outer
diameter, and M20x1.5 thread.
Pressurized oil then travels to the crankshaft main bearings, connecting
rod bearings, camshaft bearings, rocker shaft, and valve tappets. A
pressure relief valve protects the system from over-pressurization at
high engine speeds. Piston cooling jets are not installed, as thermal
loads on this naturally aspirated engine remain within acceptable
limits.
Oil Capacity (with filter): 6.0 L (6.3 qt).
Recommended Oil Grade: SAE 15W-40 or SAE 30, API CF or higher.
Oil Pressure (rated speed, warm engine): 40 to 50 psi (276 to 345 kPa).
The cooling system is a pressurized, sealed, thermostatically controlled
circulation circuit. A belt-driven centrifugal water pump, mounted on
the front of the engine, circulates coolant through the cylinder block
water jacket, cylinder head, and radiator. A wax-pellet thermostat
located in a housing at the front of the cylinder head regulates coolant
flow.
A bypass circuit allows coolant to circulate within the engine during
warm-up until the thermostat reaches its opening temperature. The system
uses a cross-flow or vertical-flow radiator with a pressure cap. An
engine-driven fan mounted on the water pump pulley draws air through the
radiator core. Coolant capacity varies based on radiator size and
application.
Engine Coolant Capacity (engine only): 3.5 L (3.7 qt).
Thermostat Start Opening Temperature: 77°C (170°F) to 82°C (180°F).
Thermostat Fully Open Temperature: 95°C (203°F).
Recommended Coolant: Ethylene glycol antifreeze mixed 50% with distilled
water.
Electrical System: 12-volt negative ground. The system includes a
gear-reduction starter motor (approximately 2.0 kW) and a belt-driven
alternator (approximately 40 to 55 amp output depending on application).
Glow plugs (three units) are energized via a glow relay and a timer or
manual switch on the instrument panel.
Starting Aid: Glow plugs installed in each pre-combustion chamber.
Recommended pre-glow time: 5 to 10 seconds at 0°C (32°F). An intake air
heater is not fitted.
Governor: Mechanical, centrifugal-type governor integrated into the
injection pump. Maintains engine speed from idle (1100 rpm) to maximum
rated speed under varying loads.
Air Cleaner: Dry-type, single-stage or two-stage paper element filter. A
restriction indicator is optional.
Dry Weight (without starter, alternator, or flywheel): 150 kg (331 lb).
Overall Length (front pulley to flywheel face): 650 mm (25.6 in).
Overall Width (exhaust manifold outer to injection pump outer): 450 mm
(17.7 in).
Overall Height (oil pan bottom to rocker cover top): 600 mm (23.6 in).
Crankshaft Centerline Height (from bottom of oil pan): 180 mm (7.1 in).
Oil Change Interval: 250 hours for normal industrial duty. Reduce to 125
hours for dusty environments or sustained high ambient temperature
operation. Oil Filter Replacement: At every oil change. Use filter
element C809J or equivalent. Fuel Filter Replacement: 250 hours. Drain
water separator weekly if operating in humid climates. Valve Clearance
(cold engine, mechanical lash adjusters): Intake: 0.020 in (0.50 mm).
Exhaust: 0.020 in (0.50 mm). Inspect and adjust every 500 hours.
Glow Plug Inspection: Test resistance at 500 hours. Replace if heating
element shows open circuit or short to ground. Injector Service
Interval: Test spray pattern and crack pressure every 1000 hours.
Replace nozzle tips at 2000 hours or if engine exhibits white smoke at
start-up or rough idle. Injection Timing Check: 16° BTDC. Verify using a
timing light and dynamic timing meter at 1000 hours or after pump
removal.
Air Cleaner Service: Replace primary element when restriction indicator
shows 5.0 kPa. Maximum element life 500 hours in normal conditions.
Coolant Replacement: 1000 hours or 2 years. Drive Belt (fan/alternator):
Inspect for cracks, glazing, or fraying at 250 hours. Replace at 500
hours or earlier if damage is visible. Starter Motor Inspection: Clean
commutator and check brush length at 1000 hours. Minimum brush length:
0.20 in (5 mm).
Cylinder Head Bolts, Stage 1: 30 lb-ft (41 Nm).
Cylinder Head Bolts, Stage 2: 50 lb-ft (68 Nm).
Cylinder Head Bolts, Stage 3: 70 lb-ft (95 Nm).
Connecting Rod Bolts: 40 lb-ft (54 Nm).
Main Bearing Cap Bolts: 65 lb-ft (88 Nm).
Flywheel Bolts: 65 lb-ft (88 Nm).
Flywheel Housing Bolts (to block): 35 lb-ft (47 Nm).
Crankshaft Pulley Bolt (center): 80 lb-ft (108 Nm).
Camshaft Thrust Plate Bolts: 15 lb-ft (20 Nm).
Rocker Arm Shaft Bracket Bolts: 18 lb-ft (24 Nm).
Valve Cover Nuts: 7 lb-ft (10 Nm).
Injection Pump Mounting Nuts: 18 lb-ft (24 Nm).
Injection Pump Drive Gear Bolt: 40 lb-ft (54 Nm).
Injector Hold-Down Clamp Bolts: 20 lb-ft (27 Nm).
High-Pressure Fuel Line Nuts (at pump and injector): 22 lb-ft (30 Nm).
Glow Plug (to cylinder head): 15 lb-ft (20 Nm).
Oil Pump Mounting Bolts: 15 lb-ft (20 Nm).
Water Pump Mounting Bolts: 18 lb-ft (24 Nm).
Thermostat Housing Bolts: 15 lb-ft (20 Nm).
Starter Motor Mounting Bolts: 28 lb-ft (38 Nm).
Alternator Pivot Bolt: 30 lb-ft (41 Nm).
Oil Pan Bolts: 10 lb-ft (14 Nm).
The Isuzu 3KC2 engine serves in a wide range of mobile and stationary
industrial equipment across global markets.
Mini Excavators:
Hitachi EX12, EX15, EX20UR, EX22, EX30.
Hanix SB20, H50B.
Sumitomo S90F3, S70FX3.
Compact Wheel Loaders:
Bobcat 843B, 843HC, 853, 853C, 853H, 853HC.
Gehl SL3410, SL3610, SL3615, SL3645.
Air Compressors:
Air Man PDS90S.
Air Man PDS125S.
Denyo DPS-90SSB2, DPS-90SST.
Generator Sets:
Denyo DCA-10SS, DCX-88WSS.
Magnum MMG25FHI, MMG25FHI Super Start.
Forklifts:
Heli CPCD20-W7, CPCD20-W8, CPCD20-W9, CPCD25-W8
Heli CPCD30-W7, CPCD30-W8, CPCD35-W4.
Shangli CPCD35, CPCD40.
Industrial Machinery:
IHI IS10F, IS10G, IS10S, IS12G, IS14G, IS25G, IS27G, IS28G, IS30F,
IS40GX.
Kato HD-307 excavator.
Kobelco SK60, SK60-2, SK70SR, SK75UR excavators.
JCB JS70, JS70 Mono excavators.
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