Page organisation in this revision
- Page type
- Technical article
- Subject
- Engines
- Parent
- Section level
- Applies to
- No ECU-specific applicability
- Tool groups
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- Manufacturers
- Not recorded in this older revision
Changes from revision 3 to revision 4
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BMW automotive engine families listed as M42. Specifications below retain the source's separate family and variant labels.
Family specifications
BMW M42
FieldReported valueManufacturerBMWProduction1989–1996ConfigurationNaturally aspirated straight-4Displacement1.8 L (1,796 cc)Cylinder bore84 mm (3.31 in)Piston stroke81 mm (3.19 in)Cylinder block materialCast ironCylinder head materialAluminiumValvetrainDOHC , 16VCompression ratio10.0:1Fuel systemFuel injectionFuel typePetrolPredecessorBMW M40SuccessorBMW M44
Variant specifications
Versions
EngineDisplacementPowerTorqueYearM42B181,796 cc (109.6 cu in)100 kW (136 PS; 134 hp) at 6,000 rpm172 N⋅m (127 lb⋅ft) at 4,600 rpm1989-1992 ( E30 )M42B181,796 cc (109.6 cu in)103 kW (140 PS; 138 hp) at 6,000 rpm175 N⋅m (129 lb⋅ft) at 4,500 rpm1992-1996 ( E36 )
Recorded vehicle applications
M42B18
1989–1991 E30 318is1990–1992 E30 318i (only North American models)1992–1995 E36 318i (only North American and South African models)1991–1995 E36 318is1994–1995 E36 318ti
BMW automotive engine directory
Design, development and variant notes
The M42 combines an iron block and aluminium head with a chain-driven twin-cam, 16-valve layout and hydraulic tappets. It uses Bosch Motronic M1.7 with a separate ignition coil pack; late engines gained a variable-length DISA intake.
From September 1993 BMW changed the timing-chain idler gear to a curved guide and revised the front casing. The source also describes upper oil-pan bolt loosening on the E30's two-piece sump arrangement; inspect the actual installation before drawing conclusions.
Variant dimensions and compression
These values are associated with the named variant and source qualifier; equipment and market specifications can differ. A dash means the value is not listed here.
VariantBore (mm)Stroke (mm)Compression ratioSource qualifierM42B188481——
Data adapted from the cited Wikipedia revision by Wikipedia contributors under CC BY-SA 4.0. Production dates and fitments reflect that revision; verify the exact engine code, market and vehicle before applying a specification.
Sources
Curated reference notes. Applicability follows the cited sources; hardware testing by this wiki is not implied.
Wikipedia: List of BMW engines. Wikipedia contributors; CC BY-SA 4.0. Source revision oldid 1382309748; accessed 2026-11-10.Wikipedia: BMW M42. Wikipedia contributors; CC BY-SA 4.0. Source revision oldid 1372840469; accessed 2026-11-10.
Further Wikipedia-sourced detailsThe following additional information is drawn from the cited Wikipedia revision by Wikipedia contributors, available under CC BY-SA 4.0. An open-ended date reflects the source snapshot, not confirmed current production or fitment.Additional technical and variant notesS42B20 is a racing development, not the ordinary M42B18 road engine. The article describes 1,999 cc, individual throttles, two injectors per cylinder and dry-sump lubrication, with quoted outputs rising from 206 kW in 1994 to 235 kW in 1997.Page organisation changed
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Revision 3: BMW M42 engines
BMW automotive engine families listed as M42. Specifications below retain the source's separate family and variant labels.
Family specifications
BMW M42
| Field | Reported value |
|---|
| Manufacturer | BMW |
| Production | 1989–1996 |
| Configuration | Naturally aspirated straight-4 |
| Displacement | 1.8 L (1,796 cc) |
| Cylinder bore | 84 mm (3.31 in) |
| Piston stroke | 81 mm (3.19 in) |
| Cylinder block material | Cast iron |
| Cylinder head material | Aluminium |
| Valvetrain | DOHC , 16V |
| Compression ratio | 10.0:1 |
| Fuel system | Fuel injection |
| Fuel type | Petrol |
| Predecessor | BMW M40 |
| Successor | BMW M44 |
Variant specifications
Versions
| Engine | Displacement | Power | Torque | Year |
|---|
| M42B18 | 1,796 cc (109.6 cu in) | 100 kW (136 PS; 134 hp) at 6,000 rpm | 172 N⋅m (127 lb⋅ft) at 4,600 rpm | 1989-1992 ( E30 ) |
| M42B18 | 1,796 cc (109.6 cu in) | 103 kW (140 PS; 138 hp) at 6,000 rpm | 175 N⋅m (129 lb⋅ft) at 4,500 rpm | 1992-1996 ( E36 ) |
Recorded vehicle applications
M42B18
- 1989–1991 E30 318is
- 1990–1992 E30 318i (only North American models)
- 1992–1995 E36 318i (only North American and South African models)
- 1991–1995 E36 318is
- 1994–1995 E36 318ti
BMW automotive engine directory
Design, development and variant notes
The M42 combines an iron block and aluminium head with a chain-driven twin-cam, 16-valve layout and hydraulic tappets. It uses Bosch Motronic M1.7 with a separate ignition coil pack; late engines gained a variable-length DISA intake.
From September 1993 BMW changed the timing-chain idler gear to a curved guide and revised the front casing. The source also describes upper oil-pan bolt loosening on the E30's two-piece sump arrangement; inspect the actual installation before drawing conclusions.
Variant dimensions and compression
These values are associated with the named variant and source qualifier; equipment and market specifications can differ. A dash means the value is not listed here.
| Variant | Bore (mm) | Stroke (mm) | Compression ratio | Source qualifier |
|---|
| M42B18 | 84 | 81 | — | — |
Data adapted from the cited Wikipedia revision by Wikipedia contributors under CC BY-SA 4.0. Production dates and fitments reflect that revision; verify the exact engine code, market and vehicle before applying a specification.
Sources
Curated reference notes. Applicability follows the cited sources; hardware testing by this wiki is not implied.
Revision 4: BMW M42 engines
BMW automotive engine families listed as M42. Specifications below retain the source's separate family and variant labels.
Family specifications
BMW M42
| Field | Reported value |
|---|
| Manufacturer | BMW |
| Production | 1989–1996 |
| Configuration | Naturally aspirated straight-4 |
| Displacement | 1.8 L (1,796 cc) |
| Cylinder bore | 84 mm (3.31 in) |
| Piston stroke | 81 mm (3.19 in) |
| Cylinder block material | Cast iron |
| Cylinder head material | Aluminium |
| Valvetrain | DOHC , 16V |
| Compression ratio | 10.0:1 |
| Fuel system | Fuel injection |
| Fuel type | Petrol |
| Predecessor | BMW M40 |
| Successor | BMW M44 |
Variant specifications
Versions
| Engine | Displacement | Power | Torque | Year |
|---|
| M42B18 | 1,796 cc (109.6 cu in) | 100 kW (136 PS; 134 hp) at 6,000 rpm | 172 N⋅m (127 lb⋅ft) at 4,600 rpm | 1989-1992 ( E30 ) |
| M42B18 | 1,796 cc (109.6 cu in) | 103 kW (140 PS; 138 hp) at 6,000 rpm | 175 N⋅m (129 lb⋅ft) at 4,500 rpm | 1992-1996 ( E36 ) |
Recorded vehicle applications
M42B18
- 1989–1991 E30 318is
- 1990–1992 E30 318i (only North American models)
- 1992–1995 E36 318i (only North American and South African models)
- 1991–1995 E36 318is
- 1994–1995 E36 318ti
BMW automotive engine directory
Design, development and variant notes
The M42 combines an iron block and aluminium head with a chain-driven twin-cam, 16-valve layout and hydraulic tappets. It uses Bosch Motronic M1.7 with a separate ignition coil pack; late engines gained a variable-length DISA intake.
From September 1993 BMW changed the timing-chain idler gear to a curved guide and revised the front casing. The source also describes upper oil-pan bolt loosening on the E30's two-piece sump arrangement; inspect the actual installation before drawing conclusions.
Variant dimensions and compression
These values are associated with the named variant and source qualifier; equipment and market specifications can differ. A dash means the value is not listed here.
| Variant | Bore (mm) | Stroke (mm) | Compression ratio | Source qualifier |
|---|
| M42B18 | 84 | 81 | — | — |
Data adapted from the cited Wikipedia revision by Wikipedia contributors under CC BY-SA 4.0. Production dates and fitments reflect that revision; verify the exact engine code, market and vehicle before applying a specification.
Sources
Curated reference notes. Applicability follows the cited sources; hardware testing by this wiki is not implied.
Further Wikipedia-sourced details
The following additional information is drawn from the cited Wikipedia revision by Wikipedia contributors, available under CC BY-SA 4.0. An open-ended date reflects the source snapshot, not confirmed current production or fitment.
Additional technical and variant notes
S42B20 is a racing development, not the ordinary M42B18 road engine. The article describes 1,999 cc, individual throttles, two injectors per cylinder and dry-sump lubrication, with quoted outputs rising from 206 kW in 1994 to 235 kW in 1997.