BMW M10 (M43) engine

The BMW M10 (M43) engine is a 2 liter displacement gasoline power unit that could develop a maximum power of up to 109 horsepower. This engine can be found under the hood of the BMW third series E21 in coupe bodywork.

M10 (M43) engine specifications

Advantages

The M43 power unit was designed to maximize practicality with simplicity. This has resulted in all four cylinders being arranged in a single row, which is a classic arrangement. This made the engine very easy and inexpensive to repair, and almost all service stations can do the job. The engines are quite successful, which led to their large distribution, so it is not difficult to find the required spare parts.

For the production of the cylinder head was used aluminum alloy of high strength, and the cylinder block itself was cast from cast iron. This solution from Bavarian engineers resulted in the engine being as light as possible, but at the same time, its reliability was unquestionable. The engine’s driving characteristics met the needs of customers, and its endurance was surprising. The cylinder block was easy to bore, unlike the aluminum blocks used today.

The engine is positioned at a 30-degree inclination to the right of its axis. Thanks to this solution, the Bavarian engineers managed to minimize the negative impact of inertial forces. This significantly increases the service life of the power unit without the need for deterioration of technical characteristics. Only to postpone overhaul it is necessary to pour only original lubricating fluid into the engine, as well as to use high-quality gasoline.

Engineers also thought about the location of the exhaust and intake manifolds, and ensured that they are located on opposite sides of the engine. This solution allows for very easy access to all engine components during repair and maintenance. Thanks to this feature, the cost of repairs is significantly reduced, as there are no additional difficulties caused by design features.

Disadvantages

One of the most common problems that owners of cars with such motors under the hood may have is related to cracks in the cylinder block. Most often, the place of formation of defects is the threaded hole intended for fixing the cylinder head and the channels of the cooling jacket. The main causes of such problems are overheating of the power unit, as well as incorrect bolt tightening torque. As a result of crack formation, coolant enters the oil, which leads to increased wear of the rubbing parts. Today, it is very difficult to find such a cylinder block without cracks, as the defect is common for almost all motors.

The cam-rocker pair in the timing mechanism is also characterized by a short service life. Its increased wear can lead to failure of the rockers, which leads to difficulties in adjusting the thermal clearances of the valves. If the valves are not adjusted correctly, motorists may experience unpleasant clunking, as well as increased wear on the timing components.

Air flowmeters are very much afraid of slamming into the air beat. This sometimes causes the flowmeter blade to bend, which leads to a permanent jamming of the accelerator pedal when the pedal is depressed. Therefore, the ignition timing must be adjusted with special care.

Owners of cars with such engines under the hood may encounter problems caused by the carburetor. But this occurs only in the case of improper adjustment of the unit, or failure of the seals.

Even though the cylinder head of a power unit is not very long, beware of rising temperatures. The cylinder head may become warped or the cylinder head gasket may be punctured. Also, such a malfunction may cause a crack in the head.

In general, these engines are considered to be quite reliable, and have proven to be one of the best motors from the Bavarians. Most of the problems are caused not by a tricky design, but by high wear and tear and old age.

Technical specifications

The M10 (M43) is a two-liter power unit with a carbureted power system. The engine was intended for installation on the BMW 320 in the E21 body. The maximum power this engine can develop is 109 horsepower at 5.8 thousand rpm. Peak torque of 160 Nm can be obtained at 3700 borotas.

The BMW M43 motor was equipped with a Solex 32/32 DIDTA twin-chamber carburetor equipped with an automatic choke. The previous engine was equipped with a mechanical throttle. This technology made it possible to ensure optimal starting and the engine’s operating temperature. It also made it possible to improve exhaust gas treatment.