Mitsubishi 6B31

Mitsubishi 6B31The Mitsubishi 6B31 is a 3.0 liter (2,998 cc, 182.9 cu in) V6, four-stroke cycle gasoline engine manufactured by Mitsubishi Motors since 2005.

The Mitsubishi 6B31 engine has an aluminum block with iron liners and aluminum cylinder heads, a pentroof type combustion chamber, a single overhead camshaft (SOHC), four-valve designs with valve timing electronic control system (MIVEC), electronic spark-advance control type ignition system, and electronic control multi-point fuel injection system.

An 87.6 mm (3.45 in) cylinder bore and 82.9 mm (3.26 in) piston stroke give the engine a total of 3.0 L of displacement. The compression ratio rating was 9.5:1 up to 2010, and 10.5:1 after 2010.

The Mitsubishi 6B31 engine produced 220 PS (162 kW; 217 HP) at 6,250 rpm of horsepower before 2010 or 230 PS (169 kW; 227 HP) at 6,250 rpm after 2010 and 276 N·m (28.1 kg·m, 203.4 ft·lb) at 4,000 rpm of peak torque before 2010 or 291 N·m (29.7 kg·m, 214.5 ft·lb) at 4,000 rpm after 2010.

General information

Engine Specifications
Engine code 6B31
Layout Four stroke, V6, 60°
Fuel type Gasoline
Production 2005-
Displacement 3.0 L, 2,998 cc (182.9 cu in)
Fuel system Electronic control MPI
Power adder None
Power output Before 2010: 220 PS (162 kW; 217 HP) at 6,250 rpm
After 2010: 230 PS (169 kW; 227 HP) at 6,250 rpm
Torque output Before 2010: 276 N·m (28.1 kg·m, 203.4 ft·lb) at 4,000 rpm
After 2010: 291 N·m (29.7 kg·m, 214.5 ft·lb) at 4,000 rpm
Firing order 1-2-3-4-5-6
Dimensions (L x H x W):

Cylinder block

The 6B31 has an aluminum cylinder block with iron cylinder liners, cylinder bore is 87.6 mm (3.45 in) and the piston stroke is 82.9 mm (3.26 in), the compression ratio is 10.5:1, for engines before 2010 – 9.5:1.

The pistons are each fitted with two compression rings and a single oil ring. The pistons are made of a special aluminum alloy. The connecting rods are made of highly rigid, forged carbon steel.

Cylinder block
Cylinder block alloy Aluminium
Compression ratio: Before 2010: 9.5:1
After 2010: 10.5:1
Cylinder bore: 87.6 mm (3.45 in)
Piston stroke: 82.9 mm (3.26 in)
Number of piston rings (compression / oil): 2/1
Number of main bearings: 4
Block Height: 215.0 mm (8.46 in)
Cylinder inner diameter (standard): 87.600 mm (3.4488 in)
Piston skirt diameter (standard): 87.600 mm (3.4488 in)
Piston ring side clearance: Top 0.040-0.080 mm (0.0016-0.0031 in)
Second 0.030-0.070 mm (0.0012-0.0028 in)
Piston ring end gap: Top 0.180-0.330 mm (0.0071-0.013 in)
Second 0.280-0.480 mm (0.011-0.0189 in)
Oil 0.100-0.600 mm (0.0039-0.0236 in)
Piston pin diameter: 22.000 mm (0.8661 in)
Crankshaft main journal diameter: 69.000 mm (2.7165 in)
Crankpin diameter: 53.000 mm (2.0866 in)

Cylinder head

The engine has aluminum cylinder heads with a single belt-driven overhead camshaft and MIVEC (MITSUBISHI INNOVATIVE VALVE TIMING ELECTRONIC CONTROL SYSTEM).

Cylinder head
Cylinder head alloy Aluminum
Cylinder head height: 120.0 mm (4.7 in)
Valve Arrangement: SOHC, belt drive
Valves: 26 (4 valves per cylinder)
Valve length: INTAKE 111.84 mm (4.4031 in)
EXHAUST 114.04 mm (4.4898 in)
Valve spring free length: INTAKE 63.77 mm (2.5106 in)
EXHAUST 59.90 mm (2.3583 in)

Maintenance data

Compression pressure
Standard value 1,650 kPa (239 psi) at 200 rpm
Minimum 1,150 kPa (167 psi) at 200 rpm
Differences of the cylinders (limit) 98 kPa (14 psi) at 200 rpm
Valve clearance
Intake valve 0.17-0.23 mm (0.0067-0.0091 in)
Exhaust valve 0.27-0.33 mm (0.0106-0.013 in)
Oil system
Recommended engine oil SAE 0W-20
Oil type API API: SM or higher
Engine oil capacity (Refill capacity) 4.6 L (4.86 US. qt, 4.05 Imp. qt.)
Ignition system
Spark plug NGK ILKR7B-8, Denso SXU22HDR8
Spark plug gap 0.7-0.8 mm (0.0276-0.0315 in)

Vehicle applications

Model Years Produced
Mitsubishi Outlander 2007-
Mitsubishi Challenger 2010-
Mitsubishi Pajero Sport 2012-
Author: Sergei Wers
About: Co-founder and CEO of a multi-brand auto repair shop (engine repair, chassis repair, body repair and painting) for over 15 years. I have been developing internet sites with technical specifications for more than seven years.

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