The M42B18 powertrain was a follower of the M40 series, more specifically the M40B18 unit. Production of the engine started at the BMW Steyr automobile factory in 1989. A few months later, the M42B18 was released here, which became the millionth copy assembled at this plant.
As for the characteristics of the M42B18, the motor is an in-line four-cylinder unit. The M42B18 1.8-liter gasoline engine differs from its predecessor in that it offers higher performance in the lower rev range. The M42B18 engine has a sixteen-valve cylinder head, two camshafts, improved combustion chamber. The design of the power plant still has hydrocompensators, which eliminate the need for independent adjustment of valve clearances. The diameter of the intake valve is 33 mm, the exhaust valve – 30.5 mm. The cylinder diameter is 84 mm, and the piston stroke is 81 mm.
In addition, the M42B18 motor is equipped with lightweight connecting rods and pistons, modified crankshaft. The unit is equipped with a more reliable timing drive – chain drive. Features of the M42B18 engine are the presence of a fan manifold, a stepped throttle valve, updated exhaust system, combustion chamber, modified electronics. In addition, the motor is presented in two variations: with or without a catalytic converter. The engine is able to use unleaded fuel with the marking 95.
Despite the recognition by motorists of reliability and positive feedback about the decent quality of the installation, the engine did not become widely used in further models.
Motor M42B18 ceased to be assembled at the factory since 1996, when it was replaced by a 1.9-liter follower series M44, with improved timing.
Characteristics of the M42 engine
| Manufacturing | Munich Plant |
| Engine make | M42 |
| Years of production | 1989-1996 |
| Cylinder block material | cast iron |
| Power system | injector |
| Type | row |
| Number of cylinders | 4 |
| Valves per cylinder | 4 |
| Piston stroke, mm | 81 |
| Cylinder diameter, mm | 84 |
| Compression ratio | 10 |
| Engine displacement, cc | 1796 |
| Engine power, hp/rpm | 140/6000 |
| Torque, Nm/rpm | 175/4500 |
| Fuel | 95 |
| Environmental standards | Euro 2 |
| Engine weight, kg | – |
| Fuel consumption, l/100 km (for 318is E36) – city – highway – mixed. |
10.9 6.4 7.7 |
| Oil consumption, gr./1000 km | to 1000 |
| Engine oil | 0W-30 0W-40 5W-30 5W-40 10W-40 |
| How much oil in the engine, liters | 5.0 |
| Oil change is carried out, km | 7000-10000 |
| Engine operating temperature, deg. | 90-95 |
| Engine life, thousand kilometers – according to the factory data – in practice |
– 300+ |
| Tuning, hp. – potential – without loss of resource |
300+ n.d. |
| Motor installed | BMW 318i E30 BMW 318i E36 BMW Z3 |
Benefits
Due to the manufacturers’ improvements to the water-cooled cooling system, the quality and operation of the thermostat has improved. In addition, mechanics have refined the water pump, which has prevented constant leaks. According to reviews of BMW M42B18 owners, the engine is characterized by reliability, a high level of quality. Experts note the high position of the motor in the rating of engines, as well as its wide popularity among motorists.
The advantage of the engine is low fuel consumption, maintainability, the possibility of carrying out independent repair work.
Disadvantages
Initially, the M42B18 motor was characterized by smooth operation and high quality, but over a long period of time, the contract engine gradually begins to show some problems.
Knocks and unnatural noises under the hood are associated with the wear of camshafts, rocker arms, hydrocompensators. RPM floating is the cause of a possible air intake. It is also worth checking the mass air flow sensor, throttle valve, which needs cleaning. Oil leakage occurs when the gasket is punctured. Engine overheating is observed in case of radiator, pump, thermostat failure. It is also worth checking the plastic tubes of the cooling system for cracks and breaks. Engine twitching during acceleration is solved by cleaning the injectors. The unwillingness of the motor to start is associated with malfunctions of spark plugs, coil, gasoline pump, wires.
Modifications
The power plant has a single modification M42B18. Power of the M42B18 engine can reach 140 horses at 6000 rpm. The torque is equal to 175 Nm. The engine meets the environmental standards EURO 2. Fuel consumption of the unit in mixed mode does not exceed 7.7 liters per 100 km of travel. Engine oil should be changed after 7,000 – 10,000 km. For BMW M42B18 it is recommended to use oil of viscosity 0W30, 0W40, 5W30, 5W40, 10W40. Filling volumes are 5.0 liters. M42B18 engine resource is more than 300,000 km, which is considered a pretty good result.
Chip tuning
According to experts, a quality overhaul will be better than tuning for the M42B18. It will be more profitable to do a swap with a replacement with m50b25. As for the tuning event specifically, it is recommended to purchase sports camshafts Dbilas264-272 s. The elements are equipped in the design with reinforced springs, sports exhaust manifold, cold intake, standard receiver. After flashing, the motor is capable of adding up to 30 horses. To increase the power characteristics of the M42B18 it is necessary to replace the intake with a four-throttle, but the engine will be unsuitable for traveling in the city.
To turbocharge the engine, you should replace the standard connecting rod and piston group with a forged one for a compression ratio of 8.5, install 630cc injectors and a 63+mm sport exhaust. Ideally it is worth to work on the brakes. As a result of all activities, the M42B18 Turbo will produce up to 300 horsepower. It should be noted that this pleasure is quite expensive, often it is cheaper to buy a ready-made turbocharged installation.