BMW M40 Straight-4 engine
| Production period: | 1987-1994 |
| Manufacturer: | BMW |
| How it works: | Otto |
| Engine Type: | R4 |
| Valve control: | OHC |
| displacement: | 1596-1795 cm 3 |
| Fuel supply: | manifold injection |
| Engine charging: | none |
| Power: | 73-85 kW |
| Previous model: | M10 |
| Successor: | M43 |
The BMW M40 is an inline-four SOHC piston engine which replaced the M10 and was produced from 1987–1995.
The M40 is a water-cooled four-cylinder gasoline engine with a crankcase made of gray cast iron . The cylinder spacing is 91 mm.
The engine has a cast crankshaft with eight counterweights. The cross-flow cylinder head consists of chill casting. The overhead, belt driven five bearings camshaft of the engine is made of chilled cast iron manufactured and operated per cylinder via drag levers each an inclined by 14 ° inlet and an outlet; the intake valve discs are 42 mm larger than the 36 mm exhaust valves. They have a hydraulic valve clearance compensation. Furthermore, the camshaft of the BMW M40, although made of shell-molded, is susceptible to "shrinkage", which is caused by the direct sliding of the drag levers on the camshaft. Mixture preparation is carried out by means of intake manifold injection , which is controlled by the Bosch Motronic M 1.3. It contains the Lamba probe for the regulated three-way catalyst . Note: The four-valve version is the BMW M42 .
Displacement ranges from 1.6 L (1596 cc; 97.4 cu in) to 1.8 L(1796 cc; 109.6 cu in). It began to be replaced by the M43 SOHC engine in 1991, however from 1989 the M40 was produced alongside the higher performance M42 DOHC four-cylinder engine.
Compared with its M10 predecessor, the M40 uses a belt-driven camshaft, and hydraulic tappets. Like the M10, the M40 uses an iron block and an aluminium head.
Fuel injection for the E30 versions is Bosch Motronic 1.3, and the E36 versions use Motronic 1.7.
| engine type | capacity | Bore × stroke | Valves / cyl. | compression | Power at 1 / min | Torque at 1 / min | Maximum speed | catalyst | fuel | construction time |
|---|---|---|---|---|---|---|---|---|---|---|
| M40B16 | 1596 cm3 | 84 mm × 72 mm | 2 | 9.0: 1 | 73 kW (100 hp) at 5500 | 141 Nm at 4250 | 6200 min-1 | Yes | 91 RON | 1988-1994 |
| M40B16 | 1596 cm3 | 84 mm × 72 mm | 2 | 9.0: 1 | 75 kW (102 hp) at 5500 | 143 Nm at 4250 | 6200 min-1 | No | 91 RON | 1988-1994 |
| M40B18 | 1795 cm3 | 84 mm × 81 mm | 2 | 8.8: 1 | 83 kW (113 hp) at 5500 | 162 Nm at 4250 | 6200 min-1 | Yes | 91 RON | 1987-1994 |
| M40B18 | 1795 cm3 | 84 mm × 81 mm | 2 | 8.8: 1 | 85 kW (115 hp) at 5500 | 165 Nm at 4250 | xxxx min-1 | No | 91 RON |
| Engine | Displacement | Power | Torque | Redline | Year |
|---|---|---|---|---|---|
| M40B16 E30 version | 1,596 cc (97.4 cu in) | 75 kW (101 hp) @ 5,500 rpm | 143 N·m (105 lb·ft) @ 4,250 rpm | 6200 | 1987 |
| M40B16 E36 version | 73 kW (98 hp) @ 5,500 rpm | 141 N·m (104 lb·ft) @ 4,250 rpm | 6200 | 1991 | |
| M40B18 E30 version | 1,796 cc (109.6 cu in) | 85 kW (114 hp) @ 5,500 rpm | 165 N·m (122 lb·ft) @ 4,250 rpm | 6200 | 1987 |
| M40B18 E36 version | 83 kW (111 hp) @ 5,500 rpm | 162 N·m (119 lb·ft) @ 4,250 rpm | 6200 | 1991 |
M40B16
The M40B16 is a 1.6 L (1,596 cc) version of the M40, which has a bore of 84 mm (3.3 in) and a stroke of 72 mm (2.8 in). It produces 102 hp (76 kW) and 105 lb·ft (142 N·m) of torque. The E30 version uses Bosch Motronic 1.3 fuel injection, while the E36 version uses Motronic 1.7.
Applications:
- 1988–1994 E30 316i
- 1990–1994 E36 316i
- 1992–1993 Bertone Freeclimber 2
M40B18
The M40B18 is a 1.8 L (1,796 cc) version of the M40, which has a bore of 84 mm (3.3 in) and a stroke of 81 mm (3.2 in). It produces 113 hp (84 kW) and 120 lb·ft (160 N·m) of torque. Like the M40B16, the fuel injection system is Bosch Motronic 1.3 for the E30 versions and Motronic 1.7 for the E36.
Applications:
- 1987–1994 E30 318i
- 1988–1994 E34 518i
- 1992–1993 E36 318i
Description
Technical
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BMW M40 Engine Technical details and specifications (1987-1995)
Engine M40B16 BMW 3 Series (E30) 1.6L 316i
No. of cylinders /OHC
Capacity 1596 cc
Firing order 1-3-4-2
Compression ratio 9.0:1
Suitable for unleaded petrol es
Fuel system make Bosch Motronic M1.3
Diagnostic socket Yes
Ignition coil Make Bosch Type 0 221 118 335
Distributor Make Bosch
Fuel system pressure 2.94-3.06bar
Injector 15-17.5 Ohm
Oil pressure 4.0-4.3 bar
Thermostat opens 88°C© Motor car History
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BMW M40 Engine Service Guide (1987-1995)
Engine M40B16 BMW 3 Series (E30) 1.6L 316i
Spark plugs Electrode gap 0.7-0.9mm
Spark plugs Original equipment Bosch F8LCR
Spark plugs Make Champion C9YCC
Spark plugs Make NGK ZFR5F-11
Valve clearance -INLET Hydraulic
Valve clearance -EXHAUST Hydraulic
Drive belt size - alternator 9,5x1013mm
Drive belt size - PAS/AC 9.5x810 mm
Drive belt tension - alternator/PAS/AC 10mm
Engine oil grade - Normal/moderate climate 10W/40 SAE or 10W/40 SAE Synthetic
Engine oil grade - cold climate 5W/30 SAE
Engine oil grade - hot climate 20W/50 SAE
Engine oil change 4.0 litres
Tighten oil Sump drain bolt 32 Nm
Cooling system 7.0 litres
Brake fluid Type DOT 4© Motor car History
