BMW N43B20 (2.0L) engine specs and service data

The BMW N43B20 is a 2.0 L (1,995 cc, 121.7 cu·in) straight-four natural aspirated four-stroke liquid-cooled internal combustion gasoline engine, manufactured by Bayerische Motoren Werke AG on the BMW Plant Hams Hall (Coleshill, Birmingham, United Kingdom) 2007 to 2011.

A 84.0 mm (3.31 in) cylinder bore and 90.0 mm (3.54 in) piston stroke give the N43B20 engine a total of 1,995 cc of displacement. The compression ratio rating is 12.0:1.

The N43B20 had three variants:

N43B20K0 – 122 PS (90 KW; 121 HP) at 6,000 rpm of horsepower and 185 Nm (18.9 kg·m; 136.5 ft·lb) at 3,000 rpm of torque. This engine was used on the BMW 116i (E81/E87).
N43B20U0 – 143 PS (105 KW; 141 HP) at 6,000 rpm of horsepower and 190 Nm (19.4 kg·m; 140.2 ft·lb) at 4,250 rpm of torque. This version was used on the BMW 118i (E81/E87/E88) and BMW 318i (E90/E91/E92/E93).
N43B20O0 – 170 PS (125 KW; 168 HP) at 6,700 rpm of horsepower and 210 Nm (21.4 kg·m; 155.0 ft·lb) at 4,250 rpm of torque. This version was used on the BMW 120i (E81/E82/E87/E88), BMW 320i (E90/E91/E92/E93) and BMW 520i (E60/E61).

The BMW N43B20 features:

Chain-driven dual overhead camshaft (DOHC)
16 valves (2 per cylinder)
Aluminum cylinder block
Aluminum cylinder head
Direct injection fuel system
Siemens MSD 81.2 engine management system
Fully electronic throttle
VANOS (Variable Valve Timing System from BMW) for both inlet and exhaust camshafts
Pressurized lubrication system
Liquid-cooled cooling system

General information

Engine Specifications
Engine model	N43B20
Engine type	4-stroke, DOHC, inline-4
Displacement	2.0 L, 1,995 cm³, (121.7 cu·in)
Max. horsepower	N43B20K0: 122 PS (90 KW; 121 HP) at 6,000 rpm N43B20U0: 143 PS (105 KW; 141 HP) at 6,000 rpm N43B20O0: 170 PS (125 KW; 168 HP) at 6,700 rpm
Max. torque	N43B20K0: 185 Nm (18.9 kg·m; 136.5 ft·lb) at 3,000 rpm N43B20U0: 190 Nm (19.4 kg·m; 140.2 ft·lb) at 4,250 rpm N43B20O0: 210 Nm (21.4 kg·m; 155.0 ft·lb) at 4,250 rpm
Cooling system	Liquid-cooled
Lubricating system	Pressurized lubrication
Fuel system	Direct injection
Engine management system	Siemens MSD 81.2
Starting system	Electric starter 12V
Firing order:	1-3-4-2
Dimensions (L x W X H)	–
Dry weight	–

Cylinder Block and Head

Cylinder block
Cylinder block alloy:	Aluminum
Compression ratio:	12.0:1
Cylinder bore:	84.0 mm (3.31 in)
Piston stroke:	90.0 mm (3.54 in)
Cylinder internal diameter (standard):	84.000 mm (3.3071 in)
Piston skirt outer diameter (standard):	83.980-84.010 mm (3.3063-3.3075 in))
Number of piston rings (compression / oil):	2/1
Side clearance (Top):	0.020-0.060 mm (0.0008-0.0024 in))
Side clearance (Second):	0.015-0.060 mm (0.0006-0.0024 in)
Ring end gap (Top):	0.150-0.300 mm (0.0059-0.0118 in)
Ring end gap (Second):	0.200-0.400 mm (0.0079-0.0157 in)
Number of main bearings:	5
Crankshaft main journal diameter:	No. 1-4: 56.000 mm (2.2047 in) No. 5: 65.000 mm (2.5590 in)
Crankpin journal diameter:	50.000 mm (2.5590 in)
Cylinder head
Cylinder head alloy:	Aluminium
Valve arrangement:	DOHC, chain-driven
Valves:	4,(16 valves in total)
Valve head diameter (INTAKE):	30.000 mm (1.1811 in)
Valve head diameter (EXHAUST):	26.600 mm (1.0472 in)
Valve seat angle (INTAKE):	45°
Valve seat angle (EXHAUST):	45°
Valve margin (INTAKE):	1.120 mm (in)
Valve margin (EXHAUST):	1.650 mm (in)
Valve steam diameter (INTAKE):	6.000 mm (0.2362 in)
Valve steam diameter (EXHAUST):	6.000 mm (0.2362 in)

Tightening torque specs

Tightening torque specs
Main bearing cap	Step 1: 20 Nm (2.0 kgf·m; 14.8 ft·lb) Step 2: Turn all bolts 70°
Connecting rod bearing cap	Step 1: 20 Nm (2.0 kgf·m; 14.8 ft·lb) Step 2: Turn all bolts 120°
Lower part of the crankcase block	M8x40: 22 Nm (2.2 kgf·m; 16.2 ft·lb) M8x26: 22 Nm (2.2 kgf·m; 16.2 ft·lb)
Oil injectors to cylinder block	12 Nm (1.2 kgf·m; 8.9 ft·lb)
Head tightening procedure and torque specs	M10x170 Step 1: 30 Nm (3.1 kgf·m; 22.1 ft·lb) Step 2: Turn all bolts 90° Step 3: Turn all bolts 90° Step 4: Turn all bolts 45° M9x95, M9x125 Step 1: 30 Nm (3.1 kgf·m; 22.1 ft·lb) Step 2: Turn all bolts 90° Step 3: – Step 4: Turn all bolts 45°

Service Data

Compression pressure
Standard:	10-11 bar (10.1-11.2 kg/cm²; 145-160 psi)
Oil system
Lubrication system:	Pressurized lubrication
Oil type:	BMW Lognlife-04
Recommended oil:	SAE 5W-30, 5W-40
Oil capacity:	4.25 liters (4.49 US.qts, 3.74 Imp. qts)
Oil consumption , :	Up to 0.7 L/1,000 km (1 qt. per 850 miles)
Ignition system
Spark plug	NGK ZKBR7A-HTU
Spark plug gap:	0.5 mm (0.0197 in)

Applications

Model	Years Produced
BMW 116i (E81/E87)	2007–2011
BMW 118i (E81/E87/E88)	2008-2011
BMW 318i (E90/E91/E92/E93)	2007-2011
BMW 120i (E81/E82/E87/E88)	2007-2011
BMW 320i (E90/E91/E92/E93)	2007-2011
BMW 520i (E60/E61)	2007-2009

References

1. BMW TIS (Technical Information System)

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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BMW N43B20