Isuzu 3CB1 Specifications
| Engine Model: Isuzu 3CB1 |
| Engine Type: 4-stroke in-line 3-cylinder liquid-cooled diesel |
| Total Displacement: 68.1 cu.in (1.11 L) |
| Rated Engine Power: 25.1 Hp (18.7 kW) at 3200 rpm |
| Fuel System Type: Indirect injection |
____________________________________________________________________________________
The Isuzu 3CB1 is a naturally aspirated,
three-cylinder diesel engine belonging to the Isuzu "C" series. Designed
as a modern, compact alternative to the older 3L-series, this power unit
focuses on simplicity and durability in harsh operational environments.
The engine operates on the indirect injection combustion principle,
which allows for quieter running and lower mechanical stress on internal
components compared to direct injection designs.
It is certified to U.S. EPA Tier 4 Interim and Stage-IIIA emissions
standards, achieved through internal engine optimization without the
need for complex aftertreatment systems. A standard glow plug starting
aid ensures reliable cold starts. A notable feature for construction
machinery applications is the availability of a high angularity oil pan,
which maintains lubrication during operation on steep inclines. Common
uses include mini excavators, compact tractors, small wheel loaders, and
industrial generators.
The Isuzu 3CB1 is an inline, three-cylinder, four-cycle diesel engine.
Its architecture employs an overhead valve configuration with pushrods
and rocker arms actuated by a camshaft located in the cylinder block.
The combustion chamber is of the swirl-type indirect injection design,
where fuel is injected into a pre-combustion chamber before main
combustion occurs in the cylinder. This design reduces noise and the
peak pressure rise rate. The engine is naturally aspirated, drawing air
without a turbocharger, which contributes to its reliability in dusty
and remote environments.
Engine Type: Inline 3-cylinder, 4-cycle, water-cooled, OHV diesel
Displacement: 1116 cc (68.1 cu.in)
Bore x Stroke: 76 mm x 82 mm (2.99 in x 3.23 in)
Compression Ratio: 18.5:1
Combustion System: Indirect Injection (swirl pre-combustion chamber)
Aspiration: Naturally aspirated
Rated Power (Industrial): 25.1 hp (18.7 kW) @ 3200 rpm
Continuous Power: 21.3 hp (15.9 kW) @ 3200 rpm
Peak Torque: 63.5 Nm (46.8 lb-ft) @ 2300 rpm
Firing Order: 1-2-3
Emissions Standard: U.S. EPA Tier 4 Interim / Stage-IIIA
The cylinder block is a one-piece, rigid construction cast from
high-grade gray cast iron. This material provides excellent damping of
vibration and mechanical noise, a priority for operator comfort in
compact machinery. The block uses a parent-bore design with integral
cast cylinders, eliminating the need for separate wet or dry liners.
Each cylinder bore is induction hardened and precision-honed to a
plateau finish, which promotes oil retention and rapid piston ring
seating.
A deep-skirt design extends the cylinder walls below the crankshaft
centerline, increasing block stiffness and reducing the risk of
distortion under load. The crankcase is an open-deck configuration with
five main bearing webs supporting the crankshaft. The water jacket
surrounds all three cylinders and extends upward into the cylinder head
gasket sealing surface.
The cylinder head is manufactured from a high-strength aluminum alloy,
reducing overall engine weight while maintaining adequate thermal
conductivity for the indirect injection system. The cross-flow design
positions intake ports on one side and exhaust ports on the other,
minimizing heat transfer to incoming air. Each cylinder features two
valves in a vertical arrangement: one intake valve and one exhaust
valve, both made from heat-resistant silicon-chromium steel.
The valves are actuated by a pushrod system driven by a camshaft located
in the cylinder block. Valve lash adjustment is performed by setscrews
and locknuts on the rocker arms. The pre-combustion chamber housings are
pressed into the cylinder head casting, each containing a glow plug that
protrudes into the swirl chamber. These glow plugs are energized before
starting to heat the air within the pre-chamber, enabling reliable
ignition at low ambient temperatures.
The fuel system is a mechanically governed indirect injection
architecture. A self-priming, diaphragm-type fuel lift pump draws fuel
from the tank and delivers it through a replaceable cartridge-type fuel
filter to the injection pump. The inline mechanical injection pump,
mounted on the side of the cylinder block, is driven by the engine gear
train. This pump contains three plunger and barrel assemblies
corresponding to each cylinder.
A centrifugal mechanical governor integrated into the injection pump
maintains engine speed under varying loads by adjusting the fuel volume
delivered. High-pressure injection lines carry fuel from the pump to the
injection nozzles mounted in each cylinder head. Each nozzle is a
pintle-type injector with an opening pressure calibrated to ensure
proper atomization within the pre-combustion chamber. Excess fuel
returns to the tank via a spill line.
The lubrication system is a forced-feed, wet-sump design. A rotor-type
oil pump, driven by the crankshaft via the engine front gear train,
draws oil from the sump through a screened pick-up tube. Oil pressure is
regulated by a spring-loaded relief valve that bypasses excess flow back
to the sump. The oil passes through a full-flow spin-on filter
containing a paper filtration element.
From the filter, pressurized oil is distributed to the main bearings,
connecting rod bearings, camshaft bearings, rocker arm shaft, and the
mechanical fuel pump. A dipstick is provided for oil level checks. The
oil pan is a stamped steel or cast aluminum component, depending on the
application. A high angularity oil pan option is available for machinery
operating on slopes. This pan features internal baffles and a relocated
pick-up point to maintain oil supply to the pump inlet when the engine
is tilted. Oil capacity is 3.4 liters.
The cooling system is a pressurized, thermostatically controlled water
circulation system. A belt-driven, centrifugal water pump mounted on the
front engine cover circulates coolant through the cylinder block,
cylinder head, and the external radiator. Coolant flows from the lower
radiator hose into the pump, then through the cylinder block water
jacket around the cylinders, upward through the cylinder head, and
finally past the thermostat into the upper radiator hose.
A wax-pellet thermostat is located in a housing on the cylinder head.
This thermostat begins opening at 71°C and reaches full open at 85°C,
providing coolant bypass during warm-up. A radiator pressure cap
maintains system pressure of 0.5-0.7 bar above atmospheric pressure,
raising the coolant boiling point. The coolant capacity for the engine
block and head only is 0.9 liters. Total system capacity with radiator
and hoses is determined by the equipment manufacturer.
Starting System: A 12-volt electric starting motor is standard, with a
24-volt system available as an option. The starter engages with a ring
gear mounted on the engine flywheel. A starting aid is provided in the
form of glow plugs located in each pre-combustion chamber. These glow
plugs are controlled by a timer or the engine control module and are
activated before cranking begins.
Intake System: Ambient air passes through a dry-type,
replaceable-element air cleaner. A rubber intake hose connects the air
cleaner outlet to the intake manifold mounted on the cylinder head. No
turbocharger, charge air cooler, or intake air heater is present.
Exhaust System: Exhaust gases exit the cylinder head through a cast iron
exhaust manifold. The manifold directs gases to a vertical exhaust pipe
or a muffler. No exhaust aftertreatment devices such as a diesel
oxidation catalyst or diesel particulate filter are required for EPA
Tier 4 Interim certification.
Electrical System: A 12-volt alternator driven by a V-belt charges the
battery and powers the machine electrical loads. The alternator output
is approximately 40-60 amperes depending on the specification. An engine
stop solenoid or a mechanical shutdown cable stops fuel flow when the
engine is switched off.
Length: 570 mm (22.4 in).
Width: 455 mm (17.9 in).
Height: 586 mm (23.1 in).
Dry Weight (without starter and alternator): 117 kg (258 lb).
Oil and Oil Filter Change: Every 250 hours or 12 months.
Fuel Filter Replacement: Every 250 hours.
Air Cleaner Element (primary) Inspection: Every 50 hours.
Air Cleaner Element Replacement: Every 500 hours.
Fuel Lift Pump Strainer Cleaning: Every 250 hours.
Valve Clearance Inspection: Every 500 hours.
Glow Plug Inspection: Every 500 hours.
Coolant Level Check: Daily.
Coolant Replacement: Every 1000 hours or 24 months.
Fan Belt Inspection and Tension Adjustment: Every 250 hours.
Injection Nozzle Inspection: Every 1000 hours.
Injection Pump Timing Check: Every 2000 hours.
Engine Oil Capacity (with filter): 3.4 L (3.6 qt).
Engine Oil Grade: SAE 10W-30, 15W-40, or 5W-40 (API CJ-4, CI-4, or CF).
Engine Coolant Capacity (block only): 0.9 L (1.0 qt).
Recommended Coolant: Ethylene glycol-based antifreeze, 30-50%
concentration.
Valve Clearance (intake and exhaust, cold engine): 0.20 mm (0.008 in).
Cylinder Head Bolts (Stage 1): 30 Nm (22 lb-ft)
Cylinder Head Bolts (Stage 2): 65 Nm (48 lb-ft)
Main Bearing Cap Bolts: 60 Nm (44 lb-ft)
Connecting Rod Cap Nuts: 40 Nm (30 lb-ft)
Flywheel Bolts: 90 Nm (66 lb-ft)
Rocker Arm Shaft Bracket Nuts: 26 Nm (19 lb-ft)
Rocker Arm Adjusting Locknuts: 12 Nm (9 lb-ft)
Injection Nozzle Holder: 35 Nm (26 lb-ft)
High-Pressure Injection Line Nuts (at pump and nozzle): 25 Nm (18 lb-ft)
Glow Plugs: 12 Nm (9 lb-ft)
Oil Filter (spin-on): 18 Nm (13 lb-ft)
Oil Pan Bolts: 12 Nm (9 lb-ft)
Water Pump Mounting Bolts: 18 Nm (13 lb-ft)
Thermostat Housing Bolts: 15 Nm (11 lb-ft)
Intake Manifold Nuts: 18 Nm (13 lb-ft)
Exhaust Manifold Nuts: 18 Nm (13 lb-ft)
Starter Motor Mounting Bolts: 30 Nm (22 lb-ft)
Alternator Pivot and Adjusting Bolts: 25 Nm (18 lb-ft)
The Isuzu 3CB1 is found in compact off-highway equipment and stationary
industrial applications.
Mini Excavators: Used in machines weighing 1.5 to 3.5 tons from
manufacturers including Isuzu, Kubota, Yanmar, and other compact
equipment brands.
Compact Tractors: Installed in sub-compact and compact utility tractors
for landscaping, estate maintenance, and small-scale agricultural
operations.
Small Wheel Loaders: Powers articulated or rigid frame loaders with
operating capacities under 1.0 ton.
Industrial Generators: Provides prime or standby power in 15-20 kVA
generator sets for construction sites, telecommunications shelters, and
backup power applications.
Skid Steer Loaders: Found in smaller frame skid steer and compact track
loader models.
Road Rollers and Compactors: Used in walk-behind and ride-on compaction
equipment.
Welding Machines: Powers diesel-driven welding generator sets for remote
field work.
____________________________________________________________________________________
| Industrial Engines Technical Specifications |
| Car Engines Technical Specifications |
| Small Engines Technical Specifications |
| Outboard Engines Technical Specifications |
