Mitsubishi 6DR5 Specifications
| Engine Model: Mitsubishi 6DR5 |
| Engine Type: 4-cycle inline 6-cylinder naturally aspirated liquid-cooled diesel |
| Total Displacement: 243.4 cu.in (3.98 L) |
| Rated Engine Power: 105 Hp (78 kW) at 3700 rpm |
| Fuel System Type: Indirect injection |
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The Mitsubishi 6DR5 is a 4.0-liter inline
6-cylinder naturally aspirated diesel engine from the DR5 engine family,
produced by Mitsubishi Heavy Industries from the early 1970s through the
1980s. This engine shares its fundamental architecture with the
4-cylinder 4DR5, utilizing an indirect injection system with a swirl
chamber combustion design and an overhead valve (OHV) valvetrain driven
by gears rather than belts or chains.
The Mitsubishi 6DR5 gained particular recognition in North America for
its brief appearance in 1978 Dodge pickup trucks, a consequence of the
1973 oil crisis and the Chrysler-Mitsubishi partnership. Beyond this
unusual North American application, the 6DR5 found widespread use in
medium-duty trucks, buses, forklifts, industrial machinery, generator
sets, and marine installations across global markets. The engine’s
inline 6-cylinder configuration delivers smoother operation and reduced
vibration compared to 4-cylinder diesel engines of equivalent
displacement.
Engine Family: Mitsubishi DR5 Series
Engine Code: 6DR5
Configuration: Inline 6-cylinder, 4-stroke, water-cooled diesel
Displacement: 3988 cc (243.4 cu.in)
Bore: 92.0 mm (3.622 in)
Stroke: 100.0 mm (3.937 in)
Compression Ratio: 20.0:1 to 21.0:1
Firing Order: 1-5-3-6-2-4
Valvetrain Configuration: Overhead Valve (OHV), 12 valves (2 per
cylinder)
Valvetrain Drive: Gear-driven from crankshaft (no timing belt or chain)
Combustion System: Indirect injection, swirl chamber type
Aspiration: Naturally aspirated
Maximum Power (Dodge Truck): 77-78 kW (105 hp) at 3500-3700 rpm
Maximum Torque (Dodge Truck): 230-245 Nm (169-184 lb-ft) at 2000-2200
rpm
Forklift Version Power: 51 kW (70 hp) at 2200 rpm
Injection Timing: 18 degrees BTDC at zero rpm
Idle Speed: 650-700 rpm
Maximum Governed Speed: 3700 rpm
The cylinder block is constructed from ribbed cast iron, providing the
rigidity required for sustained diesel operation and high mileage
durability. The inline 6-cylinder configuration utilizes seven main
bearings supporting a forged steel crankshaft, contributing to the
engine’s smooth operation and vibration reduction characteristics. The
block incorporates replaceable cylinder liners, allowing for engine
rebuilding without requiring block replacement.
The water jacket surrounds each cylinder for uniform cooling
distribution. A cast internal crankcase breather system reduces
emissions by recirculating blow-by gases. The gear-driven camshaft is
positioned within the cylinder block, with gear train housed behind the
front timing cover. The engine block features a unique adapter plate
with the Chrysler big block V8 bell housing bolt pattern for Dodge truck
applications.
The cylinder head is manufactured from cast iron using a cross-flow
design, with intake and exhaust manifolds positioned on opposite sides.
The overhead valve (OHV) arrangement employs pushrods and rocker arms
actuated by the camshaft located within the cylinder block. Two valves
per cylinder are provided, for a total of twelve valves across the
engine. Valve clearances are adjustable using threaded adjusters and
locknuts on the rocker arms.
Cold valve clearance specification is 0.35 mm (0.014 in) for both intake
and exhaust valves. The combustion chamber incorporates Ricardo-style
swirl chambers within the cylinder head, promoting thorough air-fuel
mixing before ignition. Valve seat inserts are pressed into the head,
with exhaust seats receiving high-temperature facing. The cylinder head
gasket is constructed from steel-reinforced composite material.
The fuel system employs an indirect injection configuration with swirl
chamber combustion chambers. A mechanical in-line injection pump,
mounted on the engine side and gear-driven from the camshaft, delivers
fuel to individual injection nozzles via high-pressure lines. The system
utilizes a pump-line-nozzle architecture.
A mechanical governor maintains consistent engine speed under varying
load conditions. A mechanical feed pump supplies fuel from the tank to
the injection pump. The system includes a cleanable wire screen fuel
filter as standard equipment. Glow plugs are provided for cold starting
assistance, located in the cylinder head adjacent to each swirl chamber.
The lubrication system is a wet-sump configuration utilizing a gear-type
oil pump mounted on the front of the crankshaft or driven from the
camshaft gear train. The pump draws oil through a fixed mesh pickup
screen located in the oil pan and delivers it through a full-flow
spin-on oil filter mounted on the cylinder block. System capacity varies
by oil pan configuration and application, ranging from 8.5 to 9.5 liters
(9.0 to 10.0 qt).
Recommended oil viscosity is SAE 15W-40 meeting API CC, CD, or higher
specifications for diesel engines. Oil pressure at operating speed is
maintained between 2.5-4.5 bar (36-65 psi). A pressure relief valve
limits maximum system pressure. Piston cooling jets are provided on
industrial variants for enhanced thermal management.
The cooling system is a water-cooled forced circulation configuration
utilizing a centrifugal water pump driven by the engine via the
accessory belt. The system uses a standard automotive-type radiator for
vehicle applications or a heat exchanger for marine and generator
configurations. A wax-pellet thermostat regulates coolant temperature,
commencing opening at 76-82°C (169-180°F).
System capacity varies by application, typically 12-15 liters (12.7-15.9
qt) for truck installations. The water pump bearings are standardized as
6303Z and 6203Z types. A cooling fan is mounted on the water pump
pulley. Coolant specified is ethylene glycol-based mixed with distilled
water at appropriate ratio for the expected operating environment.
Electrical System: 12-volt system with standard Chrysler alternator and
voltage regulator for Dodge truck applications.
Starting System: 12-volt starter motor with solenoid engagement; glow
plugs for cold start pre-heating.
Induction System: Dry-type air filter with replaceable paper element.
Exhaust System: Cast iron exhaust manifold with single outlet.
Engine Management: Mechanical governor; no electronic engine management.
Transmission Adapter: Big block V8 transmission bolt pattern via custom
adapter plate.
Overall Length: 1100 mm (43.3 in)
Overall Width: 600 mm (23.6 in)
Overall Height: 800 mm (31.5 in)
Dry Engine Weight (without transmission and accessories): 310 kg (683
lb)
Fully Dressed Weight (with flywheel, manifolds, alternator, starter):
350-370 kg (772-816 lb)
Oil Change Interval: 5000 km (3107 mi) or 150 operating hours under
normal service
Oil Filter Replacement: Replace at every oil change interval
Fuel Filter Cleaning: Clean wire screen element at oil change intervals
Valve Clearance (intake, cold): 0.35 mm (0.014 in)
Valve Clearance (exhaust, cold): 0.35 mm (0.014 in)
Valve Clearance Adjustment: Inspect every 20,000 km (12,427 mi) or 500
hours
Injection Timing: Verify every 1000 operating hours; static timing 18
degrees BTDC
Glow Plug Testing: Test at each major service; replace individual plugs
as required
Coolant Replacement: 1000 operating hours or 24 months
Connecting Rod Cap Nuts: 54-59 Nm (40-44 lb-ft)
Main Bearing Cap Bolts: 108-118 Nm (80-87 lb-ft)
Flywheel Bolts: 127-137 Nm (94-101 lb-ft)
Engine Oil Drain Plug: 44 Nm ± 5 Nm (32.5 lb-ft ± 4 lb-ft)
Dodge D100, D150, W150, D200, W200 Pickup Trucks: 1978 model year only,
105 hp rating, 4.0L displacement.
Mitsubishi Fuso Canter (and Jupiter) Medium-Duty Trucks: Various model
years, Japan and export markets.
Mitsubishi Rosa Buses: Early model years requiring refined 6-cylinder
diesel power.
Forklifts: Mitsubishi FD35, FD40 series; forklift version produces 70 hp
at 2200 rpm.
Construction Equipment: Excavators, loaders, and compactors.
Industrial Power Units: Stationary applications including pumps and
compressors.
Generator Sets: Prime and standby power generation from 85 kW to 90 kW
at 1800 rpm.
Marine Propulsion: Auxiliary and primary power for commercial and
recreational vessels.
Agricultural Equipment: Tractors, harvesters, and irrigation systems.
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