Mitsubishi 4B12

Mitsubishi 4B12The Mitsubishi 4B12 is an inline 2.4 liter (2,359 cc, 143.9 cu in) four-cylinder, four-stroke cycle gasoline engine manufactured by Mitsubishi Motors since 2007.

The Mitsubishi 4B12 engine has an aluminum block and cylinder head, pentroof type combustion chamber, dual overhead camshaft (DOHC), four-valve designs with valve timing electronic control system (MIVEC) on both camshafts (from 2011 for intake side only), electronic spark-advance control type ignition system, and electronic control multi-point fuel injection system.

An 88.0 mm (3.46 in) cylinder bore and 97.0 mm (3.82 in) piston stroke give the engine a total of 2.4 L of displacement. The compression ratio rating is 10.5:1.

The Mitsubishi 4B12 produced 170 PS (125 kW; 167.6 HP) at 6,000 rpm of horsepower and from 226 N·m (23 kg·m, 166.6 ft·lb) at 4,100 rpm to 232 N·m (23.7 kg·m, 171 ft·lb) at 4,100 rpm of peak torque.

General information

Engine Specifications
Engine code4B12
LayoutFour stroke, Inline-4 (Straight-4)
Fuel typeGasoline
Displacement2.4 L, 2,359 cc (143.9 cu in)
Fuel systemElectronic control MPI
Power adderNone
Power output 170 PS (125 kW; 167.6 HP) at 6,000 rpm
Torque output From 226 N·m (23 kg·m, 166.6 ft·lb) at 4,100 rpm
to 232 N·m (23.7 kg·m, 171 ft·lb) at 4,100 rpm
Firing order1-3-4-2
Dimensions (L x H x W):

Cylinder block

The 4B12 has an aluminum block, cylinder bore is 88.0 mm (3.46 in) and the piston stroke is 97.0 mm (3.82 in), the compression ratio is 10.5:1.

The pistons are each fitted with two compression rings and a single oil ring, connecting rods are 143.75 mm (5.659 in) center-to-center long. The pistons are made of a special aluminum alloy. The connecting rods are made of highly rigid, forged carbon steel.

Cylinder block
Cylinder block alloyAluminium
Compression ratio:10.5:1
Cylinder bore:88.0 mm (3.46 in)
Piston stroke:97.0 mm (3.82 in)
Number of piston rings (compression / oil):2/1
Number of main bearings:5
Block Height:
Cylinder inner diameter (standard):86.000 mm (3.3858 in)
Piston skirt diameter (standard):
Piston ring side clearance:Top0.030-0.070 mm (0.0012-0.0028 in)
Second0.030-0.070 mm (0.0012-0.0028 in))
Piston ring end gap:Top0.150-0.250 mm (0.0059-0.0098 in)
Second0.250-0.400 mm (0.0098-0.0157 in)
Oil0.100-0.350 mm (0.0039-0.0138 in)
Connecting rod center distance:143.75 mm (5.6594 in)
Crankshaft main journal diameter:56.000 mm (2.2047 in)
Crankpin diameter:48.000 mm (1.8898 in)

Cylinder head

The engine has an aluminum cylinder head with two chain-driven overhead camshafts and MIVEC (MITSUBISHI INNOVATIVE VALVE TIMING ELECTRONIC CONTROL SYSTEM) for both the intake and exhaust valves (since 2011 for the intake side only). Intake valves are 35.0 mm (1.38 in) in diameter, and the exhaust valves are 29.0 mm (1.14 in).

The MMC 4B12 engine does not have hydraulic lifters, so special valve tappets are used to adjust the valve clearance.

Cylinder head
Cylinder head alloyAluminum
Cylinder head height:
Valve Arrangement:DOHC, chain drive
Valves:16 (4 valves per cylinder)
Intake/Exhaust duration:
Valve head diameter:INTAKE35.00 mm (1.378 in)
EXHAUST29.0 mm (1.1417 in)
Valve length:INTAKE113.180 mm (4.4559 in)
EXHAUST105.887 mm (4.1688 in)
Valve stem diameter:INTAKE5.500 mm (0.2165 in)
EXHAUST5.500 mm (0.2165 in)
Cam height:INTAKE44.1 mm (1.7362 in)
EXHAUST45.0 mm (1.7717 in)

Maintenance data

Compression pressure
Standard value1,440 kPa (209 psi) at 200 rpm
Minimum1,000 kPa (145 psi) at 200 rpm
Differences of the cylinders (limit)98 kPa (14 psi) at 200 rpm
Valve clearance
Intake valve0.17-0.23 mm (0.0067-0.0091 in)
Exhaust valve0.27-0.33 mm (0.0106-0.013 in)
Oil system
Recommended engine oilSAE 0W-20
Oil type APIAPI: SM or higher
Engine oil capacity (Refill capacity)4.9 L (5.18 US. qt, 4.31 Imp. qt.)
Ignition system
Spark plugNGK DIFR5C11
Spark plug gap1.0-1.1 mm (0.0394-0.0433 in)

Vehicle applications

ModelYears Produced
Mitsubishi Delica2007-
Mitsubishi Lancer2008-
Citroën C-Crosser2008-
Peugeot 40072008-
Mitsubishi Lancer Sportback GTS2009-
Mitsubishi Lancer GTS2009-
Mitsubishi Outlander2009-
Mitsubishi Galant2010-
Mitsubishi Lancer SE AWC2012-
Mitsubishi Lancer GT Manual2013-
Mitsubishi Lancer2015-
Mitsubishi RVR2018-
Mitsubishi Outlander2020-
Mitsubishi Eclipse Cross PHEV2020-
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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