| BMW M40 engine | |
| Manufacturer: | BMW |
| Production: | 1987–1994 |
| Configuration: | Naturally aspirated straight-4 |
| Bore: | 842NaN2 |
| Stroke: | 722NaN2 812NaN2 |
| Predecessor: | BMW M10 |
| Successor: | BMW M43 |
| Valvetrain: | SOHC |
| Fueltype: | Petrol |
| Fuelsystem: | Fuel injection |
| Coolingsystem: | Water cooled |
| Management: | Bosch Motronic 1.3 or 1.7 |
| Block: | Cast iron |
| Head: | Aluminium |
The BMW M40 is an SOHC straight-four petrol engine which was produced from 1987–1994.[1] [2] It served as BMW's base model four-cylinder engine and was produced alongside the higher performance BMW M42 DOHC four-cylinder engine from 1989 onwards.
Compared with its M10 predecessor, the M40 uses a belt-driven camshaft,[3] 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,[4] and the E36 versions use Bosch Motronic 1.7.[5] [6]
Following the introduction of the BMW M43 engine in 1991, the M40 began to be phased out.
| Version | Displacement | Power | Torque | Year |
|---|---|---|---|---|
| M40B16- E30 version | 15961NaN1 | 73kW at 5,500 rpm | 1410NaN0 at 4,250 rpm | 1987 |
| M40B16- E36 version | 75kW at 5,500 rpm | 1430NaN0 at 4,250 rpm | 1991 | |
| M40B18- E30 version | 17961NaN1 | 83kW at 5,500 rpm | 1620NaN0 at 4,250 rpm | 1987 |
| M40B18- E36 version | 85kW at 5,500 rpm | 1650NaN0 at 4,250 rpm | 1991 |
The M40B16 is a 15961NaN1 version of the M40, which has a bore of 841NaN1 and a stroke of 721NaN1.[7] It produces 73kW and 105lbft.[8]
Applications:
The M40B18 is a 17961NaN1 version of the M40, which has a bore of 841NaN1 and a stroke of 811NaN1. It produces 83kW and 120lbft.
Applications: