In 2001, the outdated M43B18, M43B19, and M44B19 engines were replaced by the 4-cylinder N42B20 engine. The new engine used a light aluminum cylinder block with cast iron liners in place of a heavy cast-iron one.
New pistons, connecting rods, and a 90 mm long-stroke crankshaft are all used in the N42B20 engine. The balance shafts installed on the new block are identical to those on the M43TU.
A new twin-shaft 16-valve with a timing block was used in place of the old SOHC 8V cylinder head. The new cylinder head also has a Valvetronic intake valve lift system and a variable valve timing system on both Double-VANOS shafts. The intake and exhaust valves have diameters of 32 mm and 29 mm, respectively. Standard BMW N42 camshaft characteristics include phase 250/258 and rise to 9.7/9.7.
A DISA variable length system installed in the N42B20’s intake manifold significantly improves performance at both low and high speeds. Engine management system Bosch ME 9.2.
BMW vehicles with the 18i index were equipped with this motor.
Specifications
| Production years | 2001-2004 |
| Displacement, cc | 1995 |
| Fuel system | injector |
| Power output, hp | 143 /6000 rpm |
| Torque output, Nm | 200 /3750 rpm |
| Cylinder block | aluminum R4 |
| Block head | aluminum 16v |
| Cylinder bore, mm | 84 |
| Piston stroke, mm | 90 |
| Compression ratio | 10.0 |
| Features | Valvetronic |
| Hydraulic lifters | yes |
| Timing drive | chain |
| Phase regulator | double VANOS |
| Turbocharging | no |
| Recommended engine oil | 5W-30 |
| Engine oil capacity, liter | 4.25 |
| Fuel type | petrol |
| Euro standards | EURO 3 |
| Fuel consumption, L/100 km (for BMW 318i 2002) — city — highway — combined |
10.0 5.5 7.2 |
| Engine lifespan, km | ~275 000 |
| Weight, kg | 120 |
Disadvantages of the N42B20 engine
Valvetronic and Vanos system malfunctions account for the majority of owners’ issues;
At 100–150 thousand kilometers, the timing chain and its tensioner frequently need to be replaced; the engine is extremely hot, which significantly shortens the valve stem seals’ lifespan;
The engine may seize if non-original oil cannot withstand these temperatures;
Costly ignition coils frequently malfunction when replacing candles.