BMW M40B16 Engine (Specs, Reliability & Issues)

Updated: Jan 23

The business originally developed the 1.6-liter M40 series engine (full name M40B16) in 1988. This little engine was developed using the M40B18 engine, which has a 1.8-liter displacement and a longer stroke.


bmw M40B16 engine

Design

The cylinder block of this engine is made of cast iron, which is both durable and trustworthy. The 1.6l M40 engine, as previously indicated, has a smaller stroke crankshaft than the M40B18, although it employs the same connecting rods (the length is 140 mm).


New pistons with a different shape have been developed to keep the compression ratio at the optimum level. The 1.8L engine's intake manifold, throttle body, spark plugs, and ECU are all different.


The cylinder head is made of aluminium. On the inside, it's an 8-valve SOHC head with hydraulic tappets and lifters. Intake valves are 42 mm in diameter, while exhaust valves are 36 mm in diameter.


The M40 camshaft has a duration of 244/244 degrees (single pattern) with a valve lift of 10.6/10.6 mm. A timing belt is used to drive the camshaft.


It isn't as reliable as it seems to be. The belt's lifetime is restricted due to its low breadth. The timing belt should be changed every 25,000 miles, according to the manufacturer's recommendations. Bending valves, on the other hand, is a significant risk.


The engine was used in BMW 16i models until 1994, when the M43B16 engine, which debuted in 1993, took its place.


Specs

  • Manufacturer: Steyr Plant

  • Production years: 1987-1994

  • Cylinder block material: Cast Iron

  • Cylinder head material: Aluminum

  • Fuel type: Gasoline

  • Fuel system: Fuel injection (Bosch Motronic 1.3 (E30), Bosch Motronic 1.7 (E36))

  • Configuration: Inline

  • Number of cylinders: 4

  • Valves per cylinder: 2

  • Valvetrain layout: SOHC

  • Bore: 84.0 mm

  • Stroke: 72.0 mm

  • Displacement: 1596 cc

  • Type: Four-stroke, naturally aspirated

  • Compression Ratio: 9:1

  • Power: 73 kW (100 HP) at 5,500 rpm (E36), 75 kW (102 HP) at 5,500 rpm (E30)

  • Torque: 141 Nm (104 lb-ft) at 4,250 rpm (E36), 143 Nm (105 lb-ft) at 4,250 rpm (E30)

  • Firing order: 1-3-4-2

  • Engine oil weight: 0W-30, 0W-40, 5W-30, 5W-40, 10W-40, 15W-50

  • Engine oil capacity: 4.0L

  • Oil change interval: 9,000 miles (15,000 km) or 12 months

  • Applications: BMW 316i E30, BMW 316i E36

  • Normal engine operating temperature: °C (F): 90-95 (195-203)


Issues and Reliability

All of the engines in the M40 series are rather good. The average lifespan is 180-200 thousand kilometres. The M40B16, on the other hand, is not without problems, such as a shaky timing belt. The age of this engine is its principal issue.


The bulk of them need the rebuilding or replacement of certain outdated components, and all BMW parts are expensive.


Common Problems

  • Timing belt issues: It's much thinner than the M20 engine's.

  • Limited cylinder head oil flow: As a result, all frictional engine components in the cylinder head will wear down more quickly, requiring more frequent engine maintenance. Oil changes on a regular basis and the use of stop-start oil may assist.

  • Overheating: The wear of plastic flanges may induce overheating and coolant loss, resulting in overheating.

  • Efficiency and power issues: The failure of the lambda sensor is the source of this widespread problem.


Tuning

Tuning the M40B16 may not be the best idea, although this motor is a well rounded engine it does not respond as well to tuning as other engines do.


However, if you are looking to tune this engine, you have three primary routes of modification.


  1. Increase displacement by increasing the stroke

  2. Increase displacement further by increasing the bore

  3. Forced induction such as turbocharging


Changes & Updates

M40B16 was in operation from 1988 until 1991. This engine's basic modification is non-catalytic. At 5,500 rpm, the engine develops 102 horsepower and 105 lb-ft (143 Nm) of torque at 4,250 rpm.


In 1991, a new version of the M40B16 with catalyst was launched. It has 100 hp at 5,500 rpm and 104 lb-ft (141 Nm) torque at 4,250 rpm, which is a little less power and torque.


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