Isuzu 3CH1 Specifications
| Engine Model: Isuzu 3CH1 |
| Engine Type: 4-stroke in-line 3-cylinder liquid-cooled diesel |
| Total Displacement: 79.3 cu.in (1.26 L) |
| Rated Engine Power: 23.9 Hp (17.8 kW) at 3000 rpm |
| Fuel System Type: Indirect injection |
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The Isuzu 3CH1 is a vertical, water-cooled,
three-cylinder diesel engine from Isuzu’s compact C-Series lineup.
Designed as a modern, smaller displacement alternative to the 3CE1, this
1.3-liter powerplant employs indirect injection technology to meet
stringent emissions regulations. The 3CH1 achieves compliance with US
EPA Tier 4 Final and EU Stage V standards without requiring a diesel
particulate filter or selective catalytic reduction in most
configurations. Isuzu engineered this engine for high-demand industrial
applications including water pumps, light towers, generator sets, and
small construction equipment.
The 3CH1 is offered in two distinct configurations: a variable speed
version for applications requiring changing engine speeds and a constant
speed version for fixed-speed generator operation. The variable speed
unit produces 17.8 kW (23.9 hp) at 3000 rpm, while the constant speed
version delivers 11.1 kW (14.9 hp) at 1800 rpm. An electronic
self-priming fuel lift pump simplifies installation and operation in
remote locations. The engine features a glow plug starting aid for
reliable cold starts. Service intervals extend to 250 or 500 hours
depending on oil pan selection, with a standard factory warranty
covering two years or 2000 hours of operation.
The Isuzu 3CH1 is a three-cylinder, four-cycle, vertical water-cooled
diesel engine. Total displacement measures 1.267 to 1.3 liters, 79.3
cubic inches depending on rounding conventions. Bore is 80 mm (3.15 in)
with a stroke of 84 mm (3.31 in), producing a slightly undersquare
configuration that favors torque development at lower engine speeds. The
combustion system uses indirect injection, where fuel is injected into a
pre-combustion chamber before entering the main cylinder. Aspiration is
naturally aspirated without turbocharging.
The variable speed configuration produces maximum rated power of 17.8
kW, equivalent to 23.9 hp, at 3000 rpm. Peak torque in variable speed
form reaches 61.6 Nm (45.4 lb-ft) at 2000 rpm. The constant speed
configuration, intended for generator applications at 1800 rpm, produces
11.1 kW (14.9 hp). Emissions compliance meets US EPA Tier 4 Final and EU
Stage V standards. The electrical system operates at 12V DC. Dry weight
of the complete engine is 148 kg, equivalent to 326.3 lb.
The cylinder block is constructed from high-grade cast iron with an
inline three-cylinder arrangement. The block is cast as a single piece
with integral cylinder bores; no replaceable cylinder liners are used.
Instead, the bores are precision-machined directly into the parent cast
iron material and then honed to a finished cross-hatch pattern. This
parent bore design reduces manufacturing complexity and eliminates liner
sealing issues. The cylinder block incorporates four main bearing webs
with reinforced bulkheads to support the crankshaft.
The vertical water jacket surrounds each cylinder bore for the full
stroke length, ensuring even cooling distribution. An integral timing
gear housing is cast into the front face of the block. The block deck
surface is machined flat to accept the cylinder head gasket. Mounting
pads are cast into the block for the fuel injection pump, starter motor,
alternator, and water pump. An oil pan rail is machined on the lower
face of the block. The block includes a side-mounted oil filter housing
and a dipstick tube port.
A single cast-iron cylinder head spans all three cylinders in a
cross-flow design. Intake ports are located on one side of the head,
exhaust ports on the opposite side. The valvetrain operates as an
overhead valve (OHV) configuration with two valves per cylinder - one
intake and one exhaust - for a total of six valves. A camshaft located
within the cylinder block actuates the valvetrain.
Pushrods transfer motion through vertical bores in the cylinder head to
rocker arms. Hardened valve seat inserts are pressed into the cylinder
head, with exhaust seats manufactured from heat-resistant alloy steel.
Valve guides are pressed-in cast-iron sleeves. Valve lash is adjustable
using a screw-and-locknut mechanism on each rocker arm. The indirect
injection system requires a pre-combustion chamber for each cylinder,
located within the cylinder head.
Each pre-combustion chamber is a separate precision-machined insert made
from heat-resistant steel. This chamber receives the fuel injector
nozzle and connects to the main cylinder through a small orifice. The
cylinder head gasket is a steel laminate design. Four head bolts per
cylinder provide clamping force.
The fuel system uses mechanical indirect injection with an in-line
injection pump. A self-priming electronic fuel lift pump draws fuel from
the tank and pushes it through a spin-on fuel filter and water
separator. The electronic lift pump operates automatically when the
ignition is switched on, priming the system without manual bleeding. The
in-line injection pump is a mechanical distributor-type or individual
plunger pump driven by the engine timing gears.
The pump contains a mechanical governor that regulates fuel delivery
based on engine speed and load. Injection timing is set manually.
High-pressure fuel lines carry fuel from the injection pump to each
injector nozzle. The injectors are pintle-type nozzles designed
specifically for indirect injection systems.
Each injector is installed into the cylinder head and positioned above
the pre-combustion chamber. An electric shutoff solenoid mounted on the
injection pump controls fuel flow to stop the engine. A fuel return line
routes excess fuel and injector leakage back to the fuel tank. The
system operates at lower injection pressures than direct injection
systems, reducing internal component stress.
The lubrication system is a pressurized, forced-feed design using a
gear-type positive displacement pump. The pump is mounted on the front
of the cylinder block and driven by the crankshaft gear. Oil is drawn
from the oil pan through a pick-up tube fitted with a mesh strainer.
Total oil capacity is 3.4 liters, equivalent to 3.6 U.S. quarts. Oil
drain intervals vary from 250 hours to 500 hours depending on the
selected oil pan configuration and operating conditions. A spin-on
full-flow oil filter is mounted on the side of the cylinder block.
The filter incorporates an integral bypass valve that opens when the
filter element becomes restricted. A pressure relief valve limits
maximum oil pressure. The system supplies lubricant to the four main
bearings, three connecting rod bearings, camshaft bearings, rocker arm
assembly, timing gears, and the mechanical fuel injection pump. The oil
pan is constructed from stamped steel and includes a drain plug with a
magnetic insert to capture ferrous wear particles. Oil pressure at rated
speed is maintained between 275 and 345 kPa (40 and 50 psi).
The cooling system is pressurized and thermostatically controlled. A
centrifugal water pump is driven by a V-belt from the crankshaft pulley.
Coolant capacity for the engine block alone, excluding radiator and
external hoses, is 0.9 liter, equivalent to 1.0 U.S. quart. The total
system capacity with radiator varies by equipment manufacturer but
generally ranges from 3.5 to 4.5 liters (3.7 to 4.8 qt).
A wax-pellet thermostat is located in a housing on the front of the
cylinder head. The thermostat begins to open at a calibrated temperature
and reaches full open approximately 12°C (22°F) higher. The water pump
circulates coolant through passages cast into the cylinder block
surrounding each cylinder bore, then up through the cylinder head, past
the pre-combustion chambers and exhaust valve seats, and out to the
thermostat housing.
A radiator pressure cap maintains system pressure to raise the boiling
point of the coolant. An electric cooling fan is used on some industrial
installations, while other applications use a belt-driven fan mounted to
the water pump hub.
| Intake and Exhaust Systems |
Air Intake System: Ambient air passes through a dry-type air cleaner
before entering the intake manifold. The intake manifold distributes air
evenly to each cylinder head intake port. No turbocharger or aftercooler
is present on this naturally aspirated engine.
Exhaust System: A cast-iron exhaust manifold collects exhaust gases from
all three cylinders. The manifold is flanged for connection to the
equipment manufacturer’s exhaust pipe and silencer.
The electrical system operates at 12V DC. A gear-reduction starter motor
is mounted to the flywheel housing. A belt-driven alternator produces
charging current, with output ratings between 40 and 60 amps depending
on specification. Glow plugs are installed in the cylinder head, one per
cylinder, located within each pre-combustion chamber. The glow plugs are
controlled by a timer relay that supplies power for a predetermined
duration before and during engine cranking. This system provides
reliable cold starting down to low ambient temperatures.
Engine Governor: The mechanical governor is integrated into the
injection pump. Variable speed versions use a variable-speed governor
that allows the operator to control engine speed across the operating
range. Constant speed versions use a fixed-speed governor that maintains
a single engine speed regardless of load.
Starting Aid: In addition to glow plugs, some configurations include an
intake air heater grid installed in the intake manifold for cold weather
starting assistance.
Engine length measured from the front gear cover to the flywheel housing
mounting face is 570 mm (22.4 in). Width measured across the widest
points, including the injection pump and exhaust manifold, is 436 mm
(17.2 in). Height measured from the oil pan rail to the top of the
rocker arm cover is 586 mm (23.1 in).
Dry weight of the complete engine, including the flywheel, injection
pump, alternator, starter motor, and all covers, but excluding oil and
coolant, is 148 kg (326.3 lb). The weight with a full oil charge and
coolant adds 5 kg (11 lb). Shipping weight on a pallet with protective
packaging is 165 kg (364 lb).
Engine Oil: Capacity: 3.4 l (3.6 U.S. qt). Oil change interval: 250
hours for standard oil pan; 500 hours for extended service pan.
Recommended grade: SAE 15W-40 or SAE 10W-30. Oil Filter: Spin-on
full-flow type. Replace at every oil change. Coolant: Engine block
capacity: 0.9 l (1.0 U.S. qt). Total system capacity: 3.5 to 4.5 l (3.7
to 4.8 qt) depending on radiator. Change interval: 1000 hours or 1 year.
Fuel Filter: Spin-on type with water separator. Replacement interval:
500 hours. Fuel Lift Pump: Electronic, self-priming. No routine
maintenance required. Valve Lash (Cold): Intake: 0.20 mm (0.008 in).
Exhaust: 0.20 mm (0.008 in). Inspection interval: 500 hours. Glow Plugs:
Resistance check at 500 hours. Replace if open circuit or out of
specification. Air Cleaner: Dry cartridge type. Service when restriction
indicator shows vacuum exceeding manufacturer specification.
Thermostat: Begins opening at 76°C (169°F). Fully open at 88°C (190°F).
Low Idle Speed (Variable Speed): 1000 to 1100 rpm. High Idle Speed (No
Load): 3150 rpm maximum for variable speed. Constant Speed: Fixed at
1800 rpm or 1500 rpm depending on generator frequency requirement.
Injector Service: Inspect and test opening pressure every 1000 hours.
Cylinder Head Bolts (M12 x 1.75): 40 Nm (30 lb-ft).
Connecting Rod Cap Bolts (M9 x 1.25): 45 Nm (33 lb-ft).
Main Bearing Cap Bolts (M10 x 1.5): 60 Nm (44 lb-ft).
Flywheel Bolts (M10 x 1.25): 50 Nm (37 lb-ft).
Crankshaft Pulley Bolt (M14 x 1.5): 120 Nm (89 lb-ft).
Camshaft Thrust Plate Bolts: 20 Nm (15 lb-ft).
Rocker Arm Shaft Support Bolts: 25 Nm (18 lb-ft).
Valve Cover Nuts: 8 Nm (6 lb-ft).
Injection Pump Mounting Nuts: 25 Nm (18 lb-ft).
Injection Lines (High Pressure): 20 Nm (15 lb-ft).
Injector Hold-Down Bolts: 30 Nm (22 lb-ft).
Glow Plugs: 15 Nm (11 lb-ft).
Oil Pan Drain Plug: 35 Nm (26 lb-ft).
Starter Motor Mounting Bolts: 40 Nm (30 lb-ft).
Alternator Pivot Bolt: 25 Nm (18 lb-ft).
Water Pump Mounting Bolts: 20 Nm (15 lb-ft).
Thermostat Housing Bolts: 20 Nm (15 lb-ft).
The Isuzu 3CH1 engine serves across multiple industrial equipment
categories. Water Pumps: Trash pumps, high-pressure pumps, and
dewatering pumps from various manufacturers including Tsurumi,
Gorman-Rupp, and Multiquip. Light Towers: Portable light towers for
construction sites and event lighting. Common in Allmand, Generac, and
Wacker Neuson light tower products. Generator Sets: Small portable and
stationary generators rated from 8 kW to 12 kW prime power. Used in
backup power systems for telecommunications and remote monitoring
stations.
Construction Equipment: Small compaction equipment, including vibratory
rollers and plate compactors. Agricultural Equipment: Small irrigation
pumps and sprayer power units. Material Handling: Tow tractors and small
rough-terrain forklifts. Refrigeration Units: Transport refrigeration
and stationary cold storage power units. This engine also appears in
marine auxiliary applications for small workboats and as a propulsion
engine for small commercial vessels under 6 meters length. The constant
speed version is common in 60 Hz generator sets for the North American
market and 50 Hz sets for European markets.
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