Mitsubishi 8DC11 Specifications
| Engine Model: Mitsubishi 8DC11 |
| Engine Type: 4-cycle 8-cylinder V-block naturally aspirated liquid-cooled diesel |
| Total Displacement: 1082 cu.in (17.73 L) |
| Rated Engine Power: 380 Hp (280 kW) at 2200 rpm |
| Fuel System Type: Direct injection |
____________________________________________________________________________________
The Mitsubishi 8DC11 is a high-displacement,
naturally aspirated V8 diesel engine that served as a flagship power
unit for Mitsubishi Fuso Super Great heavy-duty trucks and various
industrial machines throughout the 1990s. As the successor to the 8DC10,
the 8DC11 offered increased displacement and a broader torque curve,
delivering the low-end pulling power required for maximum gross
combination weight operations.
This engine belongs to the Mitsubishi DC series, a family of heavy-duty
diesels known for their cast-iron durability, direct injection
combustion, and mechanical fuel systems. The 8DC11 employs a 90-degree
V8 configuration, which provides exceptional smoothness and a compact
length relative to its displacement. Unlike later electronically
controlled engines, the 8DC11 relies on an in-line mechanical injection
pump, making it serviceable with basic diesel tools.
Its naturally aspirated design eliminates turbocharger complexity, a
deliberate engineering choice for markets and applications where
simplicity and longevity under continuous high-load operation outweighed
peak power demands. The engine found additional service in large cranes,
stationary generators, and mining haul trucks, where its robust bottom
end and gear-driven camshafts provided trouble-free operation for tens
of thousands of hours.
The Mitsubishi 8DC11 is a four-stroke, compression-ignition diesel
engine. The 90-degree V8 architecture ensures inherent primary balance
without balance shafts. The direct injection combustion system places
fuel injectors centrally within each cylinder's piston bowl for
efficient mixing. Aspiration is naturally aspirated, meaning all air
enters through atmospheric pressure without a turbocharger or
supercharger.
Engine Type: 4-stroke, water-cooled, 90° V8 diesel
Number of Cylinders: 8 (V-configuration)
Total Displacement: 17.73 Liters (17,737 cc / 1082 cu.in)
Bore x Stroke: 142 mm x 140 mm (5.59 in x 5.51 in)
Compression Ratio: 18.5:1
Aspiration: Naturally aspirated
Combustion System: Direct injection
Firing Order: 1-8-4-2-7-3-6-5
Rotation (viewed from flywheel): Counterclockwise
Maximum Power: 355 to 380 hp (261 to 280 kW) at 2200 RPM
Maximum Torque: 1,180 to 1,225 Nm (870 to 904 lb-ft) at 1300-1400 RPM
Governed Maximum Speed: 2400 RPM (no-load)
Idle Speed: 550-600 RPM
The cylinder block on the 8DC11 is a cast-iron, 90-degree V8 design with
a deep-skirt construction. The deep-skirt extends the cylinder block
walls below the crankshaft centerline, providing exceptional rigidity
and reducing torsional flex under high cylinder pressures. The block
incorporates replaceable wet-type cylinder liners. These liners contact
engine coolant directly, providing superior heat transfer away from the
combustion area.
Each cylinder bank is offset (side-by-side connecting rod journals on
the crankshaft), a design that reduces engine length compared to a
flat-plane V8. The crankcase features a structural cast-iron oil pan
that contributes to overall engine stiffness. Seven main bearings
support the forged steel crankshaft. The timing gear train is located at
the front of the engine, driving the camshafts, injection pump, water
pump, and air compressor through idler gears.
Two separate cylinder heads, one for each bank, are cast in gray iron.
Each head spans four cylinders. The valve train uses an overhead valve
(OHV) configuration with pushrods and rocker arms. A single camshaft per
bank, located low in the cylinder block, actuates the valves through
mechanical lifters, hardened pushrods, and cast-iron rocker arms. Two
valves per cylinder (one intake, one exhaust) provide adequate airflow
for the naturally aspirated configuration while minimizing complexity.
Valves per Cylinder: 2 (1 intake, 1 exhaust)
Valve Configuration: Overhead valve (OHV), pushrod-actuated
Valve Seat Inserts: Induction-hardened steel (exhaust seats only)
Valve Stem Diameter (Intake): 11 mm (0.433 in)
Valve Stem Diameter (Exhaust): 11 mm (0.433 in)
Valve Lift (Intake/Exhaust): 12.5 mm (0.492 in)
Valve Clearance (Cold - Intake): 0.60 mm (0.024 in)
Valve Clearance (Cold - Exhaust): 0.70 mm (0.028 in)
Valve Adjustment Interval: 50,000 km (31,000 miles) or 1,000 operating
hours
The cylinder head gasket is a steel-reinforced composite design. Each
cylinder head is secured by a combination of M16 and M14 studs or bolts
using a multi-stage torque procedure.
The Mitsubishi 8DC11 employs a mechanical in-line injection pump system
without electronic controls. This system is entirely mechanical, relying
on a governor and manual adjustments for timing and fuel delivery. An
in-line injection pump (Bosch P-type or Mitsubishi-spec equivalent) is
gear-driven from the front timing gear train.
Injection Pump Type: In-line, mechanical, 8-cylinder (one plunger per
cylinder).
Injection Pump Governor: Mechanical, variable speed with torque control
spring.
Injector Type: Mechanical, multi-hole pencil-type (5 holes x 0.28 mm).
Injection Pressure (opening): 19.6 MPa (196 bar / 2840 psi).
Injection Timing (static): 11° to 14° before top dead center (BTDC)
depending on application.
Fuel Injection Order: Coincident with firing order 1-8-4-2-7-3-6-5.
Fuel Lift Pump: Mechanical diaphragm type, mounted on the injection
pump.
Fuel Filters: Dual spin-on filters (primary and secondary) with water
separator in primary.
Fuel Consumption at Rated Power: Approximately 215-225 g/kWh
(0.353-0.370 lb/hp-h).
The injection pump includes an automatic timing advance mechanism that
advances injection timing as engine speed increases. The mechanical
governor maintains stable idle and limits maximum no-load speed to 2400
RPM.
The lubrication system is a forced-feed, full-flow pressure system with
an integral oil cooler. A gear-type oil pump, driven from the front
timing gear train, draws oil through a suction strainer inside the oil
pan. The oil passes through a full-flow spin-on filter and then through
a water-cooled oil cooler mounted on the cylinder block.
The main oil gallery distributes oil to the seven main bearings, eight
connecting rod bearings, camshaft bearings, and the valve train. Piston
cooling jets (oil squirters) are not present on this naturally aspirated
engine, as heat loads are lower than turbocharged designs.
Lubrication Type: Forced feed, full-flow filtration
Oil Pump Type: Gear-type
Oil Capacity (including filters): 33 to 35 Liters (34.9 to 37.0 U.S.
quarts)
Oil Pressure (idle, hot 80°C): Minimum 0.7 bar (10 psi)
Oil Pressure (rated RPM, hot): 3.5-4.5 bar (51-65 psi)
Oil Filter: Full-flow spin-on, two filters in parallel on some variants
Oil Cooler: Water-cooled, tube and shell type
Oil Grade: API CD, CE, or CF-4, SAE 15W-40 (std) or SAE 30 (warm
climates)
Oil Change Interval (on-road truck): 10,000 km (6,200 miles) or 250
hours
The cooling system is a pressurized, forced-circulation liquid cooling
system. A belt-driven centrifugal water pump circulates coolant through
both cylinder banks, each cylinder head, and the oil cooler. A
wax-pellet thermostat regulates coolant temperature by controlling flow
to the radiator. The system includes a separate coolant circuit for the
cab heater on truck applications.
Cooling System Type: Pressurized, forced circulation, liquid-cooled.
Water Pump Type: Belt-driven, centrifugal.
Coolant Capacity (engine block only): 35 to 40 Liters (37.0 to 42.3 U.S.
quarts) depending on core plug configuration.
Thermostat Opening Temperature: 76.5°C (170°F).
Thermostat Fully Open Temperature: 90°C (194°F).
System Pressure (radiator cap): 0.9 bar (13 psi).
Fan Drive: Belt-driven, viscous clutch (temperature-sensing).
Coolant Type: Ethylene glycol-based, 30-50% concentration, low-silicate
formula for wet liners.
The cooling system includes a bypass circuit that allows coolant to
circulate within the engine block and cylinder heads until the
thermostat opens, preventing localized hot spots during warm-up. Each
cylinder bank has its own coolant passage separate from the other bank.
| Intake and Exhaust Systems |
Air Intake System: Air enters through a dry-type, two-stage paper
element air cleaner mounted remotely. The intake manifold is a
dual-plane design with separate plenums for each cylinder bank. No
turbocharger, charge air cooler, or intake heater is present. A mesh
flame arrester is fitted at the air intake for safety in certain
industrial applications.
Exhaust System: Each cylinder bank has a separate cast-iron exhaust
manifold. The two manifolds merge into a single exhaust pipe in the
vehicle chassis. No exhaust gas recirculation (EGR) or aftertreatment
devices are present on this engine.
Electrical System: The 8DC11 uses a 24-volt electrical system common to
heavy-duty trucks of its era. The starter is a high-torque, series-wound
type with a magnetic switch. System Voltage: 24 V DC (negative ground).
Alternator Output: 35 A (standard) or 50 A (optional). Starter Motor: 24
V, 5.5 kW (7.4 hp), reduction-gear type on later models.
Glow Plug System: Intake air heater (grid heater) or individual glow
plugs depending on market; preheat time 5-10 seconds at 0°C.
Starting Aid (Cold Climate): A thermostart flame-start system or an
electric intake air heater is fitted. The system operates automatically
when ambient temperature falls below 5°C (41°F) and the ignition switch
is in the preheat position.
Dry Weight (complete engine): 980 kg to 1,050 kg (2,160 lb to 2,315 lb)
Length (flywheel to fan pulley): 1,280 mm (50.4 in)
Width (across exhaust manifolds): 900 mm (35.4 in)
Height (oil pan to rocker cover): 1,150 mm (45.3 in)
Oil and Filter Change (on-road): 10,000 km (6,200 miles) or 250 hours.
Oil and Filter Change (industrial stationary): 250 hours.
Fuel Filter Primary (water separator): 20,000 km (12,400 miles).
Fuel Filter Secondary: 20,000 km (12,400 miles) or 500 hours.
Air Cleaner Element: Inspect at 5,000 km (3,100 miles).
Air Cleaner Element: Replace at 20,000 km.
Valve Clearance Adjustment: 50,000 km (31,000 miles) or 1,000 hours.
Coolant Replacement: 50,000 km (31,000 miles) or 1 year (with standard
coolant).
Coolant Replacement: 100,000 km with extended-life coolant.
Fan Belt Inspection: 10,000 km (6,200 miles); tension check at same
interval.
Injection Pump Timing Check: 100,000 km (62,000 miles) or 2,000 hours.
Injector Nozzle Replacement: 150,000 km (93,000 miles) or 3,000 hours.
Cylinder Head Bolts (M16 x 2.0): 285-305 Nm (210-225 lb-ft)
Cylinder Head Bolts (M14 x 1.5): 175-195 Nm (130-144 lb-ft)
Connecting Rod Nuts (M18 x 1.5): 225-245 Nm (166-181 lb-ft)
Main Bearing Cap Bolts (M20 x 2.0): 370-400 Nm (273-295 lb-ft)
Flywheel Bolts (M16 x 1.5): 315-345 Nm (232-254 lb-ft)
Crankshaft Pulley Bolt (M24 x 2.0): 450-490 Nm (332-361 lb-ft)
Injection Pump Drive Gear Nut: 150-170 Nm (111-125 lb-ft)
Injector Hold-Down Clamp Bolt (M8 x 1.25): 22-25 Nm (16-18 lb-ft)
High-Pressure Fuel Line Nuts (M12 x 1.5): 30-35 Nm (22-26 lb-ft)
Rocker Arm Shaft Bracket Bolts (M10 x 1.25): 45-55 Nm (33-41 lb-ft)
Valve Cover Bolts (M6 x 1.0): 8-10 Nm (6-7 lb-ft)
Oil Pan Bolts (M8 x 1.25): 18-22 Nm (13-16 lb-ft)
Oil Filter (spin-on): 25 Nm (18 lb-ft)
Exhaust Manifold Bolts (M10 x 1.25): 45-55 Nm (33-41 lb-ft)
Intake Manifold Bolts (M10 x 1.25): 40-50 Nm (30-37 lb-ft)
Water Pump Mounting Bolts (M10 x 1.25): 35-45 Nm (26-33 lb-ft)
Thermostat Housing Bolts (M8 x 1.25): 20-25 Nm (15-18 lb-ft)
Starter Motor Mounting Bolts (M12 x 1.5): 80-100 Nm (59-74 lb-ft)
Alternator Pivot Bolt (M10 x 1.25): 40-50 Nm (30-37 lb-ft)
Camshaft Thrust Plate Bolts (M8 x 1.25): 20-25 Nm (15-18 lb-ft)
The Mitsubishi 8DC11 is not an automotive or light-duty engine. It
served heavy commercial and industrial sectors throughout the 1990s and
early 2000s.
Heavy-Duty Trucks: Mitsubishi Fuso Super Great (FP, FU, FV series) in
6x4 and 8x4 configurations for heavy haulage, dump trucks, concrete
mixer chassis, and tanker applications.
Cargo Trucks: Mitsubishi Fuso The Great (predecessor to Super Great) for
maximum gross vehicle weight ratings above 25 tons.
Bus Chassis: Large intercity tour buses and transit buses requiring a
naturally aspirated V8 for heat rejection control in hot climates.
Cranes: Mobile hydraulic cranes (Kato, Tadano, and Hitachi-Sumitomo) in
the 40-ton to 80-ton lifting capacity range.
Generator Sets: Standby and prime power generators from 250 kVA to 350
kVA at 1500 RPM (50 Hz) or 1800 RPM (60 Hz).
Industrial Power Units: Stationary crushers, large irrigation pumps, and
industrial compressors.
Marine Propulsion: Small workboats, fishing vessels, and harbor tugs
(marine version designated 8DC11M).
Construction Machinery: Large wheel loaders and dozers (Komatsu,
Kawasaki, and Mitsubishi-branded equipment).
____________________________________________________________________________________
| Industrial Engines Technical Specifications |
| Car Engines Technical Specifications |
| Small Engines Technical Specifications |
| Outboard Engines Technical Specifications |
