BMW N42 Straight-4 DOHC Engine

The BMW N42 is a straight-4 DOHC piston engine which replaced the M43 and was produced from 2001-2004.

Compared with its M43 predecessor, the N42 features a DOHC valvetrain and variable valve timing (called VANOS by BMW). It was the first BMW engine to feature variable valve lift (called valvetronic by BMW). The N42 serves as the basis for the smaller N40 engine (which does not have valvetronic).BMW -developed petrol engine with four cylinders and 16 valves, two overhead camshafts are operated. 

The N42 is the first engine model to use the Valvetronic system , resulting in lower fuel consumption, lower exhaust emissions, better responsiveness, and smoother operation. It also has double VANOS , two gear-driven balancing shafts, and in the case of variant N42B20, the two-stage variable intake manifold DISA. Aluminum was used for the crankcase (engine block) and the cylinder head. As engine controlserved the Bosch DME ME9.2 EK924. 

In 2001, the N42 won the International Engine of the Year Award . 

The engine was used in the 3 Series (E46) in two variants, as 316i with 1796 cc and 115 hp and as 318i with 1995 cc and 143 hp. At the same time, the BMW N40 with reduced displacement without Valvetronic was developed for certain world markets .

The BMW N42 was replaced by the BMW N45 / N46 .

The N42B18 won the 1.4-1.8 L category of the International Engine of the Year competition for 2001.

In 2004, the N42 was replaced by the N46 engine.

Models

N42B18

Applications:

2001-2004 BMW 3 series E46 316i and 316ti

The N42B18 has a displacement of 1796 cc, uses Bosch DME ME9.2 fuel injection and has twin-balancing shafts
N42B20

Applications:

• 2001-2004 BMW 3 series E46 318i/318Ci/318ti

The N42B20 has a displacement of 1995 cc, uses Bosch DME ME9.2 fuel injection and has twin-balancing shafts.