Mitsubishi L3C Specifications
| Engine Model: Mitsubishi L3C |
| Engine Type: 4-cycle inline 3-cylinder naturally aspirated liquid-cooled diesel |
| Total Displacement: 49.3 cu.in (0.81 L) |
| Rated Engine Power: 16 Hp (12 kW) at 2700 rpm |
| Fuel System Type: Indirect injection |
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The Mitsubishi L3C is a 3-cylinder, vertical,
water-cooled 4-stroke diesel engine belonging to the L-Series. Produced
from 1985 onward, the L3C was developed as a compact and lightweight
power source for agricultural tractors, industrial generators, small
construction machinery, and marine applications.
The L-Series achieved a 40% weight reduction compared to previous
models, representing the world's smallest and lightest water-cooled
diesel engines in their class at the time of introduction. The L3C
features indirect injection with a swirl chamber, naturally aspirated
induction, and a rugged cast iron construction designed for continuous
operation in demanding environments.
Engine Type: Inline 3-cylinder, 4-cycle, water-cooled diesel.
Displacement: 808 cc (49.3 cu.in).
Bore: 70.0 mm (2.76 in).
Stroke: 70.0 mm (2.76 in).
Firing Order: 1-2-3.
Maximum Power Output: 15-16 hp (11-12 kW).
Aspiration: Naturally aspirated.
Valvetrain Configuration: Overhead valve configuration. The L3C utilizes
a mechanical valvetrain requiring manual valve clearance adjustment.
The cylinder block is manufactured from cast iron with an inline
3-cylinder configuration. Bore diameter measures 70.0 mm (2.76 in). The
engine features a compact, lightweight design with a 40% weight
reduction compared to conventional engines in its class.
The crankshaft is supported by four main bearings. The engine is
designed for high-speed continuous operation up to 3,600 RPM. Cylinder
liners are integrated into the cast iron block construction.
The cylinder head is manufactured from cast iron with indirect injection
swirl chamber design.
Valve Count: 6 total; 3 intake, 3 exhaust.
Valve Seat Inserts: Press-fit inserts integrated into the cast iron
cylinder head.
Valve Guides: Cast iron guides.
Valve Adjustment: Mechanical adjusters with lock nuts. Valve clearances
are set with the engine cold. Intake clearance: 0.25 mm (0.010 in);
Exhaust clearance: 0.25 mm (0.010 in). Camshaft: Cast iron camshaft
located within the cylinder block, driven by gears from the crankshaft.
Combustion Chamber: Indirect injection configuration utilizing a swirl
chamber (pre-combustion chamber) cast into the cylinder head. This
design provides smooth combustion and reduced mechanical noise. Glow
Plugs: Pencil-type glow plugs for cold starting assistance.
The fuel system employs an in-line mechanical injection pump with
indirect injection through swirl chambers. Injection Pump Type: In-line
mechanical injection pump with a mechanical governor. The governor
maintains stable idle speed and controls maximum engine speed.
Injectors: Mechanical pintle-type injectors.
Fuel Filtration: Spin-on cartridge fuel filter with integrated water
separator.
Fuel Feed Pump: Mechanical diaphragm pump integrated into the injection
pump assembly.
Cold Start Device: Manual cold start advance mechanism for cold engine
operation.
The lubrication system is a full-flow, pressurized design utilizing a
gear-type oil pump driven by the crankshaft.
Oil Pump Type: Gear-type pump within the timing gear housing.
Recommended Oil Viscosity: SAE 10W-30 (Class CD) for all seasons.
Oil Quality Requirement: API CD or later diesel-specific
classifications.
Oil Pressure: At warm idle, pressure ranges from 1.0-2.0 bar (14-29
psi).
Oil Filter: Full-flow spin-on canister type.
Crankcase Ventilation: Open system with breather hose.
The cooling system is pressurized and utilizes a centrifugal water pump
driven by the fan belt.
Water Pump Type: Centrifugal pump with cast iron housing.
Thermostat: Wax-pellet type located in the coolant outlet housing.
Opening temperature is 70-75 °C (158-167 °F) for standard applications.
Radiator: Cross-flow aluminum core. Cooling fan consists of an
engine-driven mechanical fan.
System Pressure: Radiator cap rated at 0.5-0.7 bar (7-10 psi).
Coolant Specification: Ethylene glycol-based coolant with corrosion
inhibitors.
Timing System: Gear-driven timing system with precision-ground gears
transferring drive from the crankshaft to the camshaft and injection
pump. No belts or chains are utilized.
Exhaust System: Cast iron exhaust manifold with single outlet.
Intake System: Air intake with paper element air cleaner.
Starting System: 12-volt electric starter with solenoid. Manual crank
starting available on some applications.
Electrical System: 12V system with a standard alternator; output rating
varies by application.
Overall Length: 500 mm (19.7 in) based on compact design specifications.
Overall Width: 450 mm (17.7 in).
Overall Height: 600 mm (23.6 in).
Dry Weight: 60-80 kg (132-176 lb) depending on configuration.
Bore Pitch: 80.0 mm (3.15 in).
Intake Valve Clearance (cold): 0.25 mm (0.010 in).
Exhaust Valve Clearance (cold): 0.25 mm (0.010 in).
Valve Clearance Adjustment Intervals: 250 operating hours.
Timing Gear Inspection: Gear backlash inspection at 1,000 operating
hours.
Injector Inspection: Inspection recommended every 500 operating hours.
Fuel Filter Replacement: 200 operating hours or as indicated.
Engine Oil Change Interval: Initial change at 50 hours, then every 100
hours.
Oil Filter Replacement: Initial replacement at 50 hours, then every 200
hours.
Coolant Change Interval: 500 operating hours or annually.
Glow Plug Inspection: Inspect every 500 operating hours.
Idle Speed (warm, neutral): 800-850 rpm.
Rated Engine Speed: 2,500-3,600 rpm depending on application.
Cylinder Head Bolts (M10, large): 73.5-83.4 Nm (54.2-61.5 lb-ft).
Cylinder Head Bolts (M8, small): 19.6-29.4 Nm (14.5-21.7 lb-ft).
Connecting Rod Cap Nuts: 48.8-54.2 Nm (36.0-40.0 lb-ft).
Valve Cover Nuts: 7.9-9.8 Nm (5.8-7.2 lb-ft).
Intake and Exhaust Manifold Nuts: 14.7-21.6 Nm (10.9-15.9 lb-ft).
The Mitsubishi L3C engine is installed in the following equipment
categories.
Agricultural Tractors: Mitsubishi MT15 compact tractor, Iseki TU135F,
Mitsubishi GF14. The L3C in the GF14 produces 13.3 hp at 2,500 rpm.
Industrial Equipment: Denyo MW-1050 air compressor, Denyo PCX-50SS
generator.
Lawn Mowers and Turf Equipment: Toro Groundsmaster and Workman series.
Marine Applications: Westerbeke marine generators utilizing the L3C-61WM
and L3C-62WM variants. Marine versions feature corrosion-resistant
coatings and modified cooling systems.
Industrial and Export Applications: Engine codes L3C-31xx for industrial
use and L3C-61xx/62xx for export-only configurations.
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