BMW M20B20VE engine

The M20B20VE powertrains are gasoline-fueled inline six-cylinder engines with a single camshaft. The first motors of the M20 line began production in 1977, and their production was closed in 1993. The first models that began to place under the hood of these engines were the legendary E12 of the sixth series, as well as the E21 of the third series. Motor M20B20VE is the smallest in its lineup, as they provide only two liters of working volume, and the most voluminous was the last modification of 2.7 liters. In the future, these power units served as the basis for the development of the legendary M21 motors.

Other engines were required for the third and fifth series models in 1970, due to a large increase in consumer demand. These power units had to be smaller in displacement, but still have six cylinders in a single row. The result of this need was the appearance of M20 motors, which have two liters of displacement. To this day, these modifications are the smallest among all the motors from the Bavarians, having an in-line arrangement of six cylinders.

The M20B20VE powertrains were distinguished from the M30 motors by the following figures:

• The timing chain drive was completely replaced by a belt.
• The cylinder diameter was reduced to 91 millimeters, instead of 100 millimeters.
• The angle of inclination was 10 degrees less than its counterpart – only 20 degrees.

In addition, the M20B20VE power units featured a cylinder block made of steel. The cylinder head was all aluminum. Only one camshaft was fitted, which provided a pair of valves on each cylinder.

M20B20VE engine specifications

Disadvantages

All of these motors suffer from overheating, and the M20B20VE is no exception. The cylinder head in these power units often overheats, causing it to fail. The first cause is the failure of the standard cooling system. The breakdown can be eliminated by checking for air plugs, the condition of the radiator itself, the pump, as well as adequate operation of the thermostat.

Camshaft pastels do not last long due to poor resistance to wear. This problem most often occurs on power units that have passed more than 250 thousand kilometers. As a symptom, you can distinguish a knocking sound in the camshaft area. The malfunction can only be eliminated by buying a new cylinder head. A crack in the cylinder head can also be a rare problem. This is a typical disease of M20B20VE engines, which mainly occurs due to engine overheating. Most often, the crack formation happens in the area of the 4th or 5th cylinder. It is also possible to fix the problem by purchasing a new cylinder head.

These are not all the problems faced by owners of cars with such motors. It is necessary to constantly monitor the condition of the timing belt and the position of the tensioner roller. This must be done without fail, as in the case of belt breakage one hundred percent get bending valves, less often go out of order and the pistons themselves. Do not forget about the age of these motors, which leads to their severe wear. This entails an addition in the form of age-related problems. Therefore, when choosing a car with such a power unit under the hood, it is necessary to think about the purchase. Purchasing this motor for swap into other cars is not at all a considered decision.

Description

M20B20VE is the first modification of the standard model, which was used in the fifth series E12 and third series E21 cars. With a cylinder diameter of 80 millimeters, the piston stroke of 66 millimeters was provided. The first models were equipped with a carbureted system of fuel supply to the cylinders. As a carburetor was chosen Solex 4A1, characterized by four chambers. This system allowed to provide a compression ratio of 9.2 to 1, and the maximum engine speed could be 6.4 thousand revolutions per minute. The first 320 Series cars used electrically driven fans as the cooling system. After 1979, the use of thermal clutch was introduced.

The year 1981 was marked by the replacement of the carburetor version with an injector. The Bosh K-Jetronic system was used. In the same year also began to use rounded camshaft teeth, which helped to avoid howling during engine operation. Compression of the injector version was 9.9 to 1. The LE-Jetronic system reduced the maximum speed to 6.2 thousand rpm. The engine, developed for the E30 model, has undergone significant changes in the form of a replacement cylinder head, the installation of a lightweight block and a new manifold on the intake and exhaust, which were specially adapted for the LE system.

In 1987, it was decided to replace the equipment responsible for fuel supply and injection. This equipment was a Bosh Motronic. This solution allowed to provide a maximum compression ratio of 8.8 to 1. The maximum power of the power units was up to 127 horsepower. Peak torque was equal to 174 Nm.

Chip Tuning

For as long as there have been M20B20VE engines, owners have worked out a huge number of different options to increase the powertrain’s output. The simplest and most effective option is to increase the displacement to 2.3 liters. This is simple to accomplish, as the cylinder block is the same height on these motors. To do this, you will need to purchase a new crankshaft, flywheel, connecting rods and pistons from the M20B23 modification. Also will not do without the use of a new cylinder head gasket, liners, rings and bolts. This configuration will give the opportunity to get about 150 horsepower at a small cost.

Not a bad option is also an increase in working volume up to 2.5 liters, but for more sophisticated fans of tuning there is a possibility to remake the motor into a 2.8-liter version. To do this, you will have to turn to a turner, so that he bored the cylinders to 84 millimeters, buy a crankshaft from the modification M52B28, connecting rods remain standard, pistons are installed from the version M20B25 Kat, only they should be shortened by 3 millimeters. The flywheel from the M20B20 Carb will also need to be installed. The standard cooling system will not cope with such power, so the radiator will have to be replaced. The result is a more powerful variation of the M20B28 powertrain. Replacing the camshaft and installing an intake with exhaust is also something to keep in mind.

It is also necessary to realize that after boring the cylinder block, its walls will become much thinner. This negatively affects the engine life. Such modified motors rarely last more than 20,000 kilometers.

You can also try to build a turbo version, which looks not quite attractive for the weakest power unit in its lineup, but still possible. For the realization of such an idea will have to get a turbo kit, built on the basis of a turbine Garrett T04E or Garrett GT30. It will also have to replace the exhaust system with a 2.5-inch one. Pistons with connecting rods in the standard version also will not fit – will have to install forged version, providing compression ratio up to 8.5. You will also need to replace the standard cylinder head gasket with a metal version. Stock injectors will also not work – you will have to replace them with those that provide a capacity of 440 cc, as well as install a fuel pump Walbro 255 lph. It will not do without installation of additional sensors.

Building such a variant on the basis of a model with increased volume up to 2.8 liters will allow to get about 400 liters. It will roll well, but not for a long time, as the resource is significantly reduced.

This engine is installed on the following models:

BMW 5-Series (E12)