Mitsubishi 6G72 Specifications
| Engine Model: Mitsubishi 6G72 |
| Engine Type: 4-cycle 6-cylinder V-block liquid-cooled gasoline |
| Total Displacement: 181.4 cu.in (2.97 L) |
| Rated Engine Power: 141-324 Hp (103-242 kW) at 5000-6000 rpm |
| Fuel System Type: Multi-point electronic fuel injection |
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The Mitsubishi 6G72 is a 3.0-liter V6 engine that
stands as the most prolific member of the 6G7 engine family, produced from 1986
through the early 2000s across multiple global manufacturing facilities. This
60-degree V6 configuration became the cornerstone of Mitsubishi’s
medium-displacement powertrain offerings, powering a diverse portfolio that
included passenger sedans, sports coupes, luxury grand tourers, sport utility
vehicles, and light trucks.
The engine’s longevity in production is attributed to its adaptable
architecture, which accommodated single overhead camshaft (SOHC) and dual
overhead camshaft (DOHC) valvetrains, naturally aspirated and twin-turbocharged
induction systems, and two-valve or four-valve-per-cylinder cylinder head
designs.
The 6G72 was developed during a period when the V6 configuration was becoming
the preferred layout for premium and performance-oriented vehicles. Its
60-degree bank angle was selected to minimize engine width while maintaining
inherent balance characteristics that reduced the need for large balance shafts.
The engine architecture evolved substantially over its production life.
Early SOHC 12-valve versions emphasized reliability and low-end torque for truck
and sedan applications, while later DOHC 24-valve variants, particularly the
twin-turbocharged 6G72T utilized in the Mitsubishi 3000GT / GTO and Dodge
Stealth, delivered output levels competitive with contemporary European and
Japanese performance engines. The 6G72 also formed the basis for the 3.5-liter
6G74 and 2.5-liter 6G73 variants, though the 3.0-liter version remained the most
widely distributed.
The 6G72 is a 60-degree V6, four-stroke, water-cooled gasoline engine
manufactured with cast iron cylinder block construction and aluminum alloy
cylinder heads. The engine architecture accommodates multiple valvetrain
configurations and induction systems across its production history. The
fundamental short-block dimensions - bore spacing, deck height, and main bearing
journal diameters - remained consistent across all variants, supporting
interchangeability of rotating assemblies between certain generations.
Engine Type: 60° V6, 4-cycle, water-cooled, gasoline.
Displacement: 2,972 cc (181.4 cu.in).
Bore: 91.1 mm (3.59 in).
Stroke: 76.0 mm (2.99 in).
Compression Ratio: 8.9:1 to 10.5:1.
Firing Order: 1-2-3-4-5-6.
Connecting Rod Length (center-to-center): 150.0 mm (5.91 in).
Piston Pin Diameter: 22.0 mm (0.87 in).
SOHC 12-Valve (Naturally Aspirated)
Power: 103-112 kW (141-150 hp) at 5,000 rpm.
Torque: 225-233 Nm (166-172 lb-ft) at 3,600 rpm.
Compression Ratio: 8.9:1 to 9.0:1.
SOHC 24-Valve (Naturally Aspirated)
Power: 127-145 kW (170-195 hp) at 5,500 rpm.
Torque: 255-278 Nm (188-205 lb-ft) at 4,500 rpm.
Compression Ratio: 9.0:1 to 10.0:1.
DOHC 24-Valve (Naturally Aspirated)
Power: 166-168 kW (222-225 hp) at 6,000 rpm.
Torque: 278 Nm (205 lb-ft) at 4,500 rpm.
Compression Ratio: 10.0:1 to 10.5:1.
DOHC 24-Valve Twin Turbo (6G72T)
Power: 209-242 kW (280-324 hp) at 6,000 rpm.
Torque: 415-427 Nm (306-315 lb-ft) at 2,500-4,500 rpm.
Compression Ratio: 8.0:1 to 8.5:1.
The cylinder block is manufactured from gray cast iron
using a high-pressure die-casting process, providing the rigidity necessary to
withstand the elevated cylinder pressures generated in turbocharged
applications. The block features a deep-skirt design where the block casting
extends below the crankshaft centerline, with the main bearing caps recessed
into the skirt structure. This configuration increases lateral stiffness and
reduces bore distortion under high load conditions.
The cylinder bores are machined directly into the iron casting with a
plateau-honed finish that promotes ring sealing and oil retention. The 60-degree
bank angle produces a naturally narrow engine profile, with the cylinder banks
arranged around a common crankshaft centerline. The block incorporates water
jackets surrounding each cylinder bore with coolant flow passages directed
toward the upper cylinder area where thermal loading is highest. The crankcase
region is reinforced with external ribs cast into the side walls to control
vibration and noise emissions.
Main bearing caps on naturally aspirated variants are constructed from cast iron
with a two-bolt attachment per cap. High-output turbocharged variants and select
DOHC applications utilize a four-bolt main bearing cap configuration on the
center three journals, with additional cross-bolts securing the caps to the
block sides for increased bottom-end strength under high torque loads.
Block Material: Gray cast iron.
Bore Diameter: 91.1 mm (3.59 in).
Cylinder Bank Angle: 60 degrees.
Main Bearing Quantity: 4.
Main Bearing Cap Configuration: Two-bolt (NA); four-bolt with cross-bolts
(turbo, DOHC performance variants). Balance Shafts: Equipped in select
applications; chain-driven from the oil pump.
The cylinder heads are constructed from aluminum alloy
using a permanent mold casting process. Two separate cylinder heads - one for
each bank - are secured to the block with cylinder head bolts arranged in a
specific tightening sequence. The combustion chamber design varies by valvetrain
configuration, with SOHC heads utilizing a compact wedge chamber and DOHC heads
employing a pent-roof design with centrally located spark plugs.
SOHC 12-valve heads incorporate a single camshaft per cylinder bank operating
two valves per cylinder via rocker arms that pivot on fixed shafts. The intake
and exhaust valves are arranged in a linear orientation along the cylinder head
centerline. Hydraulic lash adjusters (HLA) are integrated into the rocker arm
pivot points, automatically maintaining zero valve clearance throughout the
engine’s service life. This eliminates the need for periodic valve adjustment.
SOHC 24-valve heads utilize a single camshaft per bank operating four valves per
cylinder through a combination of roller rocker arms and lost-motion mechanisms.
Each cylinder head incorporates two intake valves and two exhaust valves
arranged in a cross-flow pattern.
DOHC 24-valve heads employ dual camshafts per cylinder bank - one for intake
valves and one for exhaust valves - with the camshafts acting directly on
bucket-type tappets. The DOHC heads incorporate hydraulic lash adjusters within
the bucket tappets or, on earlier variants, mechanical shim adjustment requiring
periodic inspection. The DOHC configuration permits independent intake and
exhaust valve timing optimization, contributing to the higher specific output of
these variants.
Valve seat inserts are pressed into the aluminum head casting, with exhaust
valve seats manufactured from a high-temperature nickel-based alloy to resist
wear and recession under sustained high-load operation.
Head Material: Aluminum alloy
Valve Configuration: SOHC 12-valve (2 valves per cylinder).
Valve Configuration: SOHC 24-valve (4 valves per cylinder).
Valve Configuration: DOHC 24-valve (4 valves per cylinder).
Valve Diameter (SOHC 12v Intake): 44.0 mm (1.73 in).
Valve Diameter (SOHC 12v Exhaust): 37.0 mm (1.46 in).
Valve Diameter (DOHC 24v Intake): 34.0 mm (1.34 in).
Valve Diameter (DOHC 24v Exhaust): 30.0 mm (1.18 in).
Valve Stem Diameter: 7.0 mm (0.28 in).
Valve Seat Angle: 45 degrees.
Camshaft Drive: Timing belt with automatic tensioner.
Hydraulic Lash Adjusters: Present on all SOHC variants and later DOHC variants.
Interference Engine: SOHC 12-valve - non-interference; all 24-valve variants -
interference design.
The fuel system configuration evolved throughout the
6G72 production run. Early SOHC 12-valve engines utilized multi-point electronic
fuel injection (MPI) with a single throttle body, air flow meter, and sequential
fuel injectors positioned in the intake manifold runners near the intake ports.
Fuel injectors were of the saturated-switch type with a resistance of 12-16
ohms. The system operated at fuel pressure regulated to 280-300 kPa (41-44 psi)
relative to manifold vacuum.
Later SOHC 24-valve and DOHC engines employed a sequential multi-point injection
system with improved injector atomization characteristics. The intake manifold
design varied by application, with some versions incorporating variable intake
manifold geometry (Mitsubishi’s “Cyclone” system) that altered intake runner
length based on engine speed to optimize torque characteristics across the
operating range. The Cyclone system utilized a butterfly valve in the intake
plenum that closed at lower engine speeds to increase intake velocity and opened
at higher speeds to maximize airflow.
Turbocharged 6G72T engines utilized a similar multi-point injection system with
larger fuel injectors and a higher-capacity fuel pump. The engine control unit
(ECU) incorporated a boost sensor and calibrated fuel maps to deliver additional
fuel under positive manifold pressure conditions. Twin intercoolers - air-to-air
units mounted in the front bumper area - reduced intake air temperature before
distribution to the combustion chambers.
Injection Type: Sequential multi-point fuel injection. Fuel Pressure (NA):
280-300 kPa (41-44 psi) with vacuum line connected. Fuel Pressure (Turbo):
330-360 kPa (48-52 psi) at idle; rises with boost pressure. Injector Resistance:
12-16 Ohms (saturated circuit design). Fuel Requirement: 91-95 octane (RON)
depending on compression ratio; premium fuel required for DOHC and turbo
variants.
The lubrication system employs a fully pressurized,
wet-sump design with a trochoid-type oil pump mounted internally at the front of
the engine and driven directly by the crankshaft nose. The oil pump consists of
an inner rotor and outer rotor assembly that generates flow with minimal
pulsation. Oil is drawn from the stamped steel or cast aluminum oil pan through
a mesh strainer positioned at the lowest point of the sump.
Pressurized oil passes through a full-flow, replaceable oil filter mounted
externally on the cylinder block. The oil filter incorporates an anti-drainback
valve to maintain filter and gallery priming during engine shutdown. From the
filter, oil enters the main oil gallery machined longitudinally through the
cylinder block, supplying the crankshaft main bearings, connecting rod bearings,
camshaft bearings, and hydraulic lash adjusters. Piston cooling is provided by
oil splash from the connecting rod bearing clearances.
Turbocharged variants incorporate additional oil feed and drain lines to supply
and return oil from the turbocharger bearings. A turbocharger oil filter or
restricted orifice is utilized in the feed line to control flow rate and prevent
bearing flooding. Some high-output applications include an oil cooler - either a
water-to-oil unit integrated with the oil filter housing or an air-to-oil cooler
mounted in the front of the engine bay - to maintain oil temperature under
sustained high-load operation.
Oil Type: SAE 5W-30 or 10W-30; synthetic oil recommended for turbocharged
variants.
Oil Capacity: 4.3-5.5 L (4.5-5.8 US qt) depending on oil pan and application.
Oil Pressure (at idle, warm): 70-100 kPa (10-15 psi).
Oil Pressure (at 3,000 rpm): 300-400 kPa (44-58 psi).
Oil Pump Type: Trochoid (internal-external gear), crankshaft-driven.
Oil Cooler: External cooler on select turbo and heavy-duty applications.
The cooling system is a pressurized, liquid-cooled
design with a belt-driven centrifugal water pump mounted on the front of the
engine. The water pump impeller circulates coolant through the cylinder block,
cylinder heads, heater core, and radiator. The cooling system is designed to
maintain consistent operating temperatures across both cylinder banks, with
coolant flowing from the pump into the block water jackets surrounding each
cylinder bank before rising into the cylinder heads.
A wax-pellet thermostat is mounted in a housing on the water pump inlet side,
regulating coolant flow to the radiator. The thermostat begins opening at a
calibrated temperature and achieves full opening within a defined temperature
range. A bypass circuit permits coolant circulation within the engine during
warm-up, bypassing the radiator until the thermostat opens.
The radiator is a cross-flow, aluminum-plastic construction with a
multi-louvered fin design optimized for the specific vehicle application. An
electric cooling fan or viscous-drive fan (depending on chassis configuration)
provides forced airflow through the radiator and condenser. Turbocharged
variants incorporate additional cooling capacity through larger radiator cores
and, in some applications, supplemental electric fans.
Coolant Type: Ethylene-glycol based antifreeze.
Coolant Capacity: 7.5-9.0 L (7.9-9.5 US qt).
Thermostat Opening Temperature: 82-88 °C (180-190 °F).
Radiator Cap Pressure: 110 kPa (16 psi).
Water Pump Type: Centrifugal, belt-driven.
| Intake and Exhaust Systems |
Intake System: The intake system incorporates a
paper-element air cleaner with an intake duct routing filtered air to the
throttle body. The throttle body houses a cable-operated butterfly valve with an
integrated idle air control (IAC) valve that regulates bypass air for idle speed
control. The intake manifold material varies by application, with aluminum
castings used on earlier engines and composite plastic manifolds introduced on
later variants.
Exhaust System: The exhaust system utilizes cast iron exhaust manifolds - one
per cylinder bank - with the manifolds merging into a single or dual exhaust
system depending on application. Turbocharged variants incorporate the
turbocharger units directly at the exhaust manifold outlets.
The 6G72 utilizes a distributor-based ignition system
on early SOHC variants, with a single distributor driven by the rear of the
front cylinder head intake camshaft. The distributor houses a crank angle sensor
that provides engine speed and position information to the ECU. Later SOHC
24-valve and DOHC variants transitioned to a distributorless ignition system
with individual coil-on-plug or coil-near-plug units for each cylinder,
eliminating the high-voltage distributor and improving ignition timing accuracy.
Timing Drive: All 6G72 variants employ a rubber timing
belt with internal fabric reinforcement. The belt drives the camshafts from the
crankshaft sprocket, with a separate tensioner pulley maintaining belt tension.
The timing belt also drives the water pump on most configurations. The belt is
protected by a plastic or metal cover. All 24-valve versions are interference
engines, meaning valve-to-piston contact occurs if the timing belt fails or
jumps teeth. The SOHC 12-valve engine is a non-interference design.
Overall Length: 580 mm (22.8 in)
Overall Width: 680 mm (26.8 in)
Overall Height: 670 mm (26.4 in)
Dry Weight (SOHC 12v): 170 kg (375 lb)
Dry Weight (DOHC Twin Turbo): 210 kg (463 lb)
Engine Oil Change: 5,000-7,500 km (3,100-4,700 mi) or 6
months.
Engine Oil Filter Change: At every oil change.
Timing Belt Replacement: 96,000 km (60,000 mi) for DOHC and turbo.
Timing Belt Replacement: 96,000-120,000 km (60,000-75,000 mi) for SOHC.
Timing Belt Tensioner Inspection: Replace with timing belt.
Spark Plug Replacement: 48,000 km (30,000 mi) for copper plugs.
Spark Plug Replacement: 96,000 km (60,000 mi) for platinum or iridium.
Spark Plug Gap (NA): 1.0-1.1 mm (0.039-0.043 in).
Spark Plug Gap (Turbo): 0.7-0.8 mm (0.028-0.031 in).
Coolant Replacement: 48,000 km (30,000 mi) or 2 years.
Drive Belt (Accessory) Inspection: Every 15,000 km (9,300 mi).
Air Filter Replacement: 30,000 km (18,600 mi).
Fuel Filter Replacement: 48,000 km (30,000 mi).
Valve Clearance Adjustment: Inspection every 96,000 km (60,000 mi) for
mechanical DOHC.
Cylinder Head Bolts (SOHC 12v NA), 1st pass: 40 Nm (30
lb-ft)
Cylinder Head Bolts (SOHC 12v NA), 2nd pass: 80 Nm (59 lb-ft)
Cylinder Head Bolts (SOHC 12v NA), Final pass: 110 Nm (81 lb-ft)
Cylinder Head Bolts (SOHC 24v NA), 1st pass: 40 Nm (30 lb-ft)
Cylinder Head Bolts (SOHC 24v NA), 2nd pass: 80 Nm (59 lb-ft)
Cylinder Head Bolts (SOHC 24v NA), Final pass: 110 Nm (81 lb-ft)
Cylinder Head Bolts (DOHC NA), 1st pass: 40 Nm (30 lb-ft)
Cylinder Head Bolts (DOHC NA), 2nd pass: 80 Nm (59 lb-ft)
Cylinder Head Bolts (DOHC NA), Final pass: 110 Nm (81 lb-ft)
Cylinder Head Bolts (Twin Turbo), 1st pass: 40 Nm (30 lb-ft)
Cylinder Head Bolts (Twin Turbo), 2nd pass: 80 Nm (59 lb-ft)
Cylinder Head Bolts (Twin Turbo), Final pass: 125 Nm (92 lb-ft)
Main Bearing Cap Bolts (Two-Bolt), 1st pass: 40 Nm (30 lb-ft)
Main Bearing Cap Bolts (Two-Bolt), Final pass: 93 Nm (69 lb-ft)
Main Bearing Cap Bolts: 40 Nm (30 lb-ft) then 74 Nm (55 lb-ft)
Main Bearing Cross-Bolts: 25 Nm (18 lb-ft)
Connecting Rod Cap Bolts, 1st pass: 20 Nm (15 lb-ft)
Connecting Rod Cap Bolts, Final pass: 45 Nm (33 lb-ft)
Camshaft Bearing Cap Bolts (DOHC): 20 Nm (15 lb-ft)
Intake Manifold Bolts (SOHC): 20-25 Nm (15-18 lb-ft)
Intake Manifold Bolts (DOHC): 22 Nm (16 lb-ft)
Exhaust Manifold Nuts: 20-30 Nm (15-22 lb-ft)
Spark Plugs: 20-30 Nm (15-22 lb-ft)
Oil Pan Bolts: 12 Nm (106 lb-in)
Water Pump Bolts: 20 Nm (15 lb-ft)
Timing Belt Tensioner Bolt: 20 Nm (15 lb-ft)
Crankshaft Pulley Bolt: 100 Nm (74 lb-ft) + 180° rotation
Flywheel / Drive Plate Bolts: 90-100 Nm (66-74 lb-ft)
The Mitsubishi 6G72 engine was utilized across an
extensive range of vehicles produced by Mitsubishi Motors, as well as vehicles
manufactured by partner companies under original equipment manufacturer (OEM)
agreements. The engine’s long production run resulted in its installation in
multiple generations of each model line.
Mitsubishi Passenger Cars:
Mitsubishi Galant / Sigma (1987-2003): SOHC 12-valve and later SOHC 24-valve
variants across multiple generations.
Mitsubishi Diamante (1990-2004): SOHC 24-valve and DOHC 24-valve variants.
Mitsubishi 3000GT / GTO (1990-1999): DOHC 24-valve naturally aspirated and DOHC
24-valve twin-turbocharged (6G72T) variants.
Mitsubishi Eclipse (1990-1999): SOHC 24-valve in Eclipse GS and DOHC 24-valve in
Eclipse GSX (shared with Dodge and Eagle variants).
Mitsubishi SUVs and Trucks:
Mitsubishi Pajero / Montero / Shogun (1988-2000): SOHC 12-valve and SOHC
24-valve variants.
Mitsubishi Challenger / Montero Sport (1996-2004): SOHC 24-valve variant.
Mitsubishi Delica / L300 (1990-1999): SOHC 12-valve variant.
Chrysler Corporation Applications (via Diamond-Star
Motors / Mitsubishi OEM supply):
Dodge Stealth (1990-1996): DOHC 24-valve naturally aspirated and DOHC 24-valve
twin-turbocharged variants (6G72T) as the R/T and R/T Turbo models.
Dodge Avenger (1995-2000): SOHC 24-valve variant.
Chrysler Sebring (1995-2000): SOHC 24-valve variant.
Plymouth Laser (1990-1994): DOHC 24-valve variant in Laser RS Turbo.
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