Mitsubishi S2E2 Specifications
| Engine Model: Mitsubishi S2E2 |
| Engine Type: 4-cycle 2-cylinder naturally aspirated liquid-cooled diesel |
| Total Displacement: 90.2 cu.in (1.48 L) |
| Rated Engine Power: 29.6 Hp (22.1 kW) at 2400 rpm |
| Fuel System Type: Indirect fuel injection |
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The Mitsubishi S2E2 is a compact, two-cylinder
diesel engine representing an evolved iteration within the S2E series,
featuring increased displacement for improved power and torque output
while maintaining a focus on mechanical simplicity and operational
reliability. This 1.478-liter, naturally aspirated power plant employs
an indirect injection combustion system with a swirl pre-combustion
chamber, delivering controlled combustion, reduced noise, and dependable
cold-start performance.
Its square bore and stroke design ensures balanced mechanical forces,
contributing to smooth power delivery suitable for both constant-speed
and moderate variable-load applications. As an evolution of the S2E,
this engine provides a direct upgrade path for equipment requiring
greater capability without a significant increase in physical size. Its
construction emphasizes durability and serviceability, with a robust
cast iron block, gear-driven valve train, and accessible service points,
making it a practical and cost-effective power solution for a range of
light industrial and agricultural machinery.
Manufacturer: Mitsubishi Heavy Industries, Ltd.
Engine Model: S2E2.
Engine Type: 4-cycle, water-cooled, vertical inline, indirect injection
diesel.
Aspiration: Naturally aspirated.
Emission Compliance: Manufactured before the implementation of
contemporary emission regulations; conforms to historical industrial
engine standards.
Management System: Mechanical fuel injection with mechanical governor.
Number of Cylinders: 2.
Bore: 98 mm (3.858 in).
Stroke: 98 mm (3.858 in).
Displacement: 1.478 L (1478 cc) (90.2 cu in).
Compression Ratio: 19:1.
Firing Order: 1-2.
Rotation Direction: Counter-clockwise when viewed from the flywheel
side.
Maximum Gross Power Output: 22.1 kW (29.6 hp) at 2,400 rpm
(representative value; specific output varies by governed speed and
application).
Maximum Gross Torque: 74 Nm (54.6 lb-ft) at 1,600 rpm.
Rated Speed: 2,200-2,400 rpm for industrial applications; 1,500 or 1,800
rpm for constant-speed generator sets. Idle Speed: 700-800 rpm.
The cylinder block is a sturdy, compact casting manufactured from
high-strength gray iron. Its design provides a solid structural
foundation for the two cylinders, with reinforced webbing between the
bores and substantial material around the main bearing saddles to manage
combustion loads. The cylinder bores are machined and honed directly
into the block material. The crankshaft is a forged steel or high-grade
nodular cast iron component, supported by three main bearings.
This three-main-bearing configuration provides essential support for the
two-throw crankshaft, with integrated counterweights engineered to
mitigate the inherent primary imbalance of the two-cylinder layout.
Connecting rods are forged steel, fitted with replaceable precision
bearing shells at the crankpin end. The piston pin is a press-fit in the
connecting rod small end. Pistons are aluminum alloy, designed with a
specific crown profile compatible with the indirect injection swirl
chamber system. The piston ring pack consists of two compression rings
and one oil control ring.
A single-piece cast iron cylinder head is utilized, secured to the block
with studs and nuts. The head accommodates one intake and one exhaust
valve per cylinder. Valve seat inserts are manufactured from hardened,
heat-resistant alloy to ensure reliable sealing and longevity. The valve
train operates on an overhead valve (OHV) design, with the camshaft
located in the cylinder block.
The camshaft is gear-driven from the crankshaft, a positive and
maintenance-free timing drive mechanism. The camshaft actuates the
valves via solid pushrods and rocker arms. Rocker arms are mounted on a
stationary shaft fastened to the cylinder head. Valve clearance is set
and maintained by a screw and locknut adjustment on each rocker arm, a
scheduled maintenance task. The cylinder head incorporates the indirect
injection pre-combustion (swirl) chamber for each cylinder, which houses
a glow plug for cold starting assistance.
The engine employs a mechanical, inline pump-line-nozzle fuel injection
system. Core components include a mechanical fuel lift pump, a
two-element inline injection pump, high-pressure steel fuel lines, and
pintle-type injectors. The injection pump is a jerk-pump design, driven
by the engine's gear train. It supplies fuel at high pressure to nozzles
that discharge into the pre-combustion swirl chamber.
A mechanical centrifugal governor, integral to the injection pump,
regulates engine speed by controlling the position of the fuel rack. The
injection timing and fuel delivery are mechanically calibrated for the
specific displacement and performance characteristics of the S2E2. Fuel
filtration involves a primary sedimentor/water separator and a secondary
fine filter, both vital for protecting the precision components of the
injection system from contamination.
Lubrication is provided by a forced-feed, full-flow wet sump system. A
gear-type oil pump, driven directly from the crankshaft, draws oil from
the sump through a pickup tube equipped with a strainer screen.
Pressurized oil is routed through a full-flow, replaceable cartridge or
canister-type oil filter. After filtration, oil enters the main oil
gallery in the block, supplying the crankshaft main and connecting rod
bearings, the camshaft bearings, and the valve gear via internal
passages and hollow pushrods.
The system is designed for reliable lubrication with a straightforward
network of internal oil passages. The specified engine oil is API CC,
CD, or CF grade. Total oil capacity is 5.0 liters (5.3 US qt), including
the filter. The oil pan is a stamped steel component.
Cooling is managed by a pressurized, pump-circulated liquid system. A
centrifugal water pump, driven by a V-belt from the crankshaft pulley,
provides coolant circulation. System operating temperature is regulated
by a wax-pellet type thermostat.
Heat rejection occurs via a tube-and-fin radiator; the cooling fan is
mounted on the engine and is V-belt driven. The increased displacement
relative to the S2E necessitates effective cooling. The cooling system
requires a mixture of ethylene-glycol antifreeze and clean water. A
50/50 mixture is standard for corrosion protection and freeze
resistance. Total cooling system capacity is 4.0 liters (4.2 US qt) for
the engine side, excluding the radiator and external hose volume.
| Intake and Exhaust Systems |
Intake System: Consists of an air cleaner (oil bath or dry element) and
a cast iron or aluminum intake manifold. Exhaust System: Comprises a
cast iron exhaust manifold and a downpipe connecting to the equipment's
exhaust silencer.
Electrical System: Operates on a 12V system. A 12V starter motor and a
12V alternator or DC generator are fitted. The engine incorporates a
glow plug system for cold starting, controlled by a key-switch or timer
module. An electric stop solenoid or manual pull cable acts on the
injection pump rack.
Length (Front Face of Block to Flywheel Housing): 573 mm (22.56 in).
Width (Overall): 550 mm (21.65 in).
Height (Overall, from sump to valve cover): 736 mm (28.98 in).
Dry Weight (with standard accessories): 180 kg (397 lb).
Engine Oil Change: Every 250 operating hours. Oil Filter Replacement:
Every oil change (250 hours). Fuel Filter Replacement: Service sediment
bowl daily; replace secondary filter element every 500 hours. Air
Cleaner Element Service: Clean oil bath or replace dry element every
100-250 hours, contingent on operational environment. Valve Clearance
Adjustment: Check and adjust every 500 operating hours.
Coolant Replacement: Drain, flush, and refill every 1,000 operating
hours or annually. Fan Belt Tension Check/Adjustment: Inspect and adjust
tension every 250 hours; replace belts showing signs of wear or
cracking. Fuel Injection System Inspection: Have injection pressure and
spray pattern checked by a specialist every 1,500 hours.
Cylinder Head Nuts: Tighten in the specified multi-step crisscross
sequence to a final torque of 108-118 Nm (80-87 lb-ft). Main Bearing Cap
Bolts: 88-98 Nm (65-72 lb-ft).
Connecting Rod Cap Bolts: 69-78 Nm (51-58 lb-ft).
Flywheel to Crankshaft Bolts: 108-118 Nm (80-87 lb-ft).
Fuel Injector Holder: 59-69 Nm (44-51 lb-ft).
Glow Plugs: 15-20 Nm (11-15 lb-ft).
Oil Pan Drain Plug: 39-49 Nm (29-36 lb-ft).
Oil Filter Canister/Cartridge: For a canister, tighten the center bolt
to 20-25 Nm (15-18 lb-ft). For a spin-on filter, hand-tighten plus 3/4
turn after gasket contact.
The Mitsubishi S2E2 engine was applied in a variety of light industrial
and agricultural equipment where its compact size, increased power over
the S2E, and reliable indirect injection performance were valued. Common
applications include: Agricultural Tractors: Compact and utility
agricultural tractors from Japanese manufacturers such as Iseki and
Satoh. Construction Equipment: Small vibratory rollers, concrete mixers,
light towers, and mobile welding units.
Generator Sets: Mobile and stationary generator sets in the 15-20 kVA
power range. Pumping Equipment: Medium-capacity irrigation pumps,
firefighting pumps, and industrial transfer pumps. Material Handling:
Light to medium-duty forklifts and hydraulic power units. Agricultural
Machinery: Powers larger implements like rotary tillers, feed grinders,
and small combine harvesters. Marine Applications: Used as an auxiliary
generator drive or propulsion engine for small fishing boats and
workboats.
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