BMW M42B18

M42B18The BMW M40B18 is a 1.8 liters (1,796 cc, 109.6 cu·in) straight-four, four-stroke cycle, natural aspirated gasoline engine from the BMW M42-family. The engine was manufactured from 1989 to 1996.

The M42B18 engine features a cast-iron cylinder block, an aluminum head with a chain-driven double overhead camshafts (DOHC) and two valves per cylinder (16 in total) with hydraulic tappets. Cylinder bore and piston stroke are 84.0 mm (3.31 in) and 81.0 mm (3.19 in), respectively. Compression ratio rating is 10.0:1.

This engine used a Multi Point Fuel Injection system (MPFI), the Bosch Motronic M 1.7 engine management system and coil-on-plug ignition system with fully electronic controlled ignition timing. Later versions of the M42 also feature a dual length intake manifold (“DISA”).

The BMW M42B18 engine produced 136.0 PS (100.0 kW; 134.0 HP) at 6,000 rpm of maximum output power and 172.0 N·m (17.5 kg·m, 126.8 ft·lb) at 4,600 rpm of peak torque for BMW 318i (E30) model (1989-1992 production years), or 140.0 PS (103.0 kW; 138.0 HP) at 6,000 rpm of horsepower and 175.0 N·m (17.8 kg·m, 129.0 ft·lb) at 4,500 rpm of torque for BMW 318i (E36) model (1992-1996).

The breakdown of the engine code is as follows:

  • M42 – Engine Family
  • B – Gasoline
  • 18 – 1.8 Liter displacement

General information

Engine Specifications
Engine code M42B18
Layout Four stroke, Inline-4 (Straight-4)
Fuel type Gasoline
Production 1989-1996
Displacement 1.8 L, 1,796 cc (109.6 cu in)
Fuel system Multi Point Fuel Injection (MPFI)
Power adder None
Max. horsepower E30: 136.0 PS (100.0 kW; 134.0 HP) at 6,000 rpm
E36: 140.0 PS (103.0 kW; 138.0 HP) at 6,000 rpm
Max. torque E30: 172.0 N·m (17.5 kg·m, 126.8 ft·lb) at 4,600 rpm
E36: 175.0 N·m (17.8 kg·m, 129.0 ft·lb) at 4,500 rpm
Firing order 1-3-4-2
Dimensions (L x H x W):

Cylinder block

Cylinder block
Cylinder block alloy Aluminum
Compression ratio: 10.0:1
Cylinder bore: 84.0 mm (3.31 in)
Piston stroke: 81.0 mm (3.19 in)
Number of piston rings (compression / oil): 2 / 1
Number of main bearings: 5
Cylinder inner diameter (standard): 84.000-84.014 mm (3.3071-3.3076 in)
Piston skirt diameter (standard): 83.985 mm (3.3065 in)
Piston ring side clearance: Top 0.020-0.200 mm (0.0008-0.0079 in)
Second 0.020-0.100 mm (0.0008-0.0039 in)
Oil 0.020-0.100 mm (0.0008-0.0039 in)
Piston ring end gap: Top 0.200-1.000 mm (0.0079-0.0394 in)
Second 0.200-1.000 mm (0.0079-0.0394 in)
Oil 0.200-1.000 mm (0.0079-0.0394 in)
Crankshaft journal diameter: 60.000 mm (2.3622 in)
Crankpin journal diameter: 45.000 mm (1.7717 in)

Cylinder head

Cylinder head
Valve Arrangement: DOHC, chain-driven
Valves: 16 (4 valves per cylinder)
Intake/Exhaust duration:
Valve head diameter: INTAKE 33.0 mm (1.2992 in)
EXHAUST 30.5 mm (1.2008 in)
Valve steam diameter: INTAKE 5.975-6.000 mm (0.2352-0.2362 in)
EXHAUST 5.960-6.000 mm (0.2346-0.2362 in)

Maintenance data

Oil system
Recommended engine oil SAE 5W-30, 10W-40
Oil type API SG or SF and better
Engine oil capacity (Refill capacity) 4.8 L (5.07 US. qt, 4.22 Imp. qt.)
Ignition system
Spark plug Bosch F7LDCR, Champion RC8DMC, NGK BKR6EK
Spark plug gap: 0.9 mm (0.0354 in)

Vehicle applications

Model Years Produced
BMW 318is (E30) 1989–1991
BMW 318i (E30) 1990–1992
BMW 318i (E36) 1992–1995
BMW 318is (E36) 1991–1995
BMW 318ti (E36) 1994–1995
ATTENTION! Dear visitors, this site is not a trading platform, an official dealer or a spare parts supplier, so we do not have any price lists or spare parts catalogs. We are an information portal and provide the technical specifications of gasoline and diesel engines.

We try to use verified sources and official documentation, however, differences between sources or errors in entering information may occur. We do not provide advice on technical issues related to the engines operation or repair. We do not recommend using provided information for engines repairing engines or spare parts ordering, use only official service manuals and spare-parts catalogs.

Be the first to comment

Leave a Reply

Your email address will not be published.