BMW M10B20 engine

All engines of the M10 range from BMW are four-cylinder SOHC power units, production of which began in 1962, and was stopped in 1988. Engine displacements ranged from 1,499 to 1,990 cubic centimeters. The M10B20 motor provided for 2 liters.

This power unit proved to be quite successful, as it showed good technical capabilities in combination with two carburetors, fuel injection, and in some cases with additional superchargers. Some 3.5 million units were produced during the entire production period. The motor featured a climactic design, and was originally called M120 (the last digits in the engine marking indicated the displacement, in this case – 2 liters). This is a legendary family of motors from the Bavarian manufacturer. All modifications, and M10B20 including, received a cast iron cylinder block, which is covered with an aluminum cylinder head.

In essence, the M10B20 engine was a previous variation of the 1.8-liter M10B18 engine, but had bored cylinders. Piston stroke did not differ from the predecessor, and was 80 millimeters. Until 1972, the installation of this power unit was provided for Neue Klasse. The maximum power of the engine in this version was 100 horsepower.

After some time, the standard crankshaft was replaced by a version with 8 counterweights, which allowed to provide 113 horses of peak power. But this engine was not fitted to production cars, it was only found under the hood of racing models.

The first version of the engine with 100 horsepower of maximum output was produced for the 2000 Typ 120 and 121, 2002 E10 and Cabriolet-Baur E114C , as well as the 2000-2002 Touring E6 models.

There is also a 120 horsepower power unit with a maximum torque of 167 Nm. This was achieved by installing two carburetors for the power system. It was most often found in the GT4 Frua, the 2002 Ti E10 and the BMW 2000 TI Typ121.

M10B20 engine specifications

Advantages

M10B20 motors had a certain number of features that allowed them to stand out from the competition of the time. From the usual Bavarian power units they also had small differences. The main distinguishing features were as follows:

• The four cylinders were arranged in a single row.
• The diameter of the cylinder exceeded the length of the piston stroke, which offered certain advantages.
• Only aluminum and cast iron were used in the production of the motor.
• The design called for the installation of 5 main bearings.
• The engine block was tilted to the right 30 degrees.
• The intake and exhaust manifolds were located on opposite sides of the powertrain.

Disadvantages

Despite the fact that the M10B20 engines are considered quite successful, they are not without flaws. Still, it is worth remembering that these are BMWs and it is pointless to tell about the problems they cause to owners. The most common typical faults are:

• Cracks formed in the cylinder block. This is the weakest point of all power units belonging to the version Most often the areas where cracks are formed are in the threaded connections provided for fixing the cylinder head, as well as in the cooling system jacket. The most common cause of cracks is engine overheating. The first symptoms may be the appearance of emulsion in the oil and a sharp decrease in the volume of coolant in the expansion tank. Through the crack, a certain volume of antifreeze begins to penetrate into the engine crankcase. Considering the rather large age, it is almost impossible to meet such a power unit without cracks.
• The eccentric washer does not please the owners of cars with such motors under the hood with a long service life. It is also not uncommon to observe premature wear of the rocker cam.
• The cylinder head gasket is made of materials that leave much to be desired in their quality, so it burns through quite often.
• All M10B20 engines have long since exhausted their service life as a lot of time has passed since the end of their production, so natural wear of the piston group is normal. This phenomenon leads to increased lubricant consumption.

Despite these shortcomings, we can say that the M10B20 motor, as well as other modifications of this family, are quite reliable. Their design is quite simple, which significantly reduces the problems with repair and maintenance. These power units also stand out and unpretentiousness to the quality of the oil and gasoline used. Despite the great age, many of these motors are still working on cars today.

This engine is installed on the following models:

BMW 5-Series (E12)