BMW M20 engine specifications. Description and main characteristics of the BMW M20 engine

The BMW M20 has firmly carved out its niche in the engine market, sitting exactly between the M10 and M30. He also lived a very long industrial life and became widespread, including in Russia, where he was actively bought in a complete set with a body number 34.

Historical reference

This engine first rolled off the assembly line in 1977 and was produced until 1993.
It was intended primarily for the new and first BMW 5th series - E12.

It was the M20 that later served as the basis for the development of engines such as the M21, M70 and V12.

Specifications

The M20 is a six-cylinder, twelve-valve engine of a fairly small volume for BMW. Compared to its predecessor, the M30, the motor has a lighter design and a belt-driven camshaft. At the same time, the M20 retains a cast iron cylinder block and an aluminum head.
The volume of the engine upon completion of all the improvements was 2.5 liters, and the power was 170 hp.
M20 weight - 113 kg.

M20 modifications on BMW 5 Series models

M20B20

M20B25

М20В27

The most common faults

When operating the M20 engine, the following problems often occur:

the formation of a crack in the cylinder head connecting the cooling cavity and the crankcase;
damage to valves when the timing belt breaks;
violation of position tension roller, that leads to heavy wear transmission of the gas distribution mechanism.

BMW M20B20 engine

Characteristics of the M20V20 engine

Production	Munich plant
Engine brand	M20
Years of release	1977-1992
Cylinder block material	cast iron
Supply system	carburetor / injector
Type of	inline
Number of cylinders	6
Valves per cylinder	2
Piston stroke, mm	66
Cylinder diameter, mm	80
Compression ratio	9.2 9.8 9.9 9.8 8.8 (see modifications)
Engine displacement, cubic cm	1991
Engine power, hp / rpm	122/6000 125/5800 126/5800 129/6000 129/6000 (see modifications)
Torque, Nm / rpm	160/4000 170/4000 170/4000 174/4000 174/4300 (see modifications)
Fuel	92-95
Environmental standards	-
Engine weight, kg	~ 113 (dry)
Fuel consumption in l / 100 km (for E30 320i) - town - track - mixed.	13.0 7.5 9.5
Oil consumption, gr. / 1000 km	up to 1000
Engine oil	5W-30 5W-40 10W-30 10W-40 10W-50 15W-50
How much oil is in the engine, l	4.25
Oil change is carried out, km	7000-10000
Engine operating temperature, deg.	~90
Engine resource, thousand km - according to the plant - on practice	- ~250-300
Tuning, h.p. - potential - without loss of resource	400+ n.d.
The engine was installed

BMW M20B20 engine reliability, problems and repair

The BMW M20B20 inline six-cylinder engine ("Spider") appeared in 1977 as a replacement for inline fours and is the ancestor of the M20 family, which also includes the 2.3-liter M20B23, 2.5-liter and M20B27 with a displacement of 2.7 liters. The M20B20 engine was used on cars with a 20i index.
The engine is based on a cast-iron cylinder block, on top of an aluminum 12-valve cylinder head with one SOHC 12V camshaft. At first, the head was used known as the 200, later it was replaced by the 731, which featured a large diameter inlet ports. The diameter of the intake valves is 40 mm, the exhaust valves are 34 mm. There are no hydraulic lifters, valve adjustment is required every 10-20 thousand km, valve clearances 0.25 mm inlet, 0.3 mm outlet. The timing belt uses a belt, which must be replaced every 50 thousand km; if the belt breaks, the engine bends the valve.
The power system on the first variations of the engine is carburetor, since 1981, carburetors have given way to mechanical and electronic injection.
In 1990, the 2-liter representative of the M20 series was replaced by new engine - .

BMW M20B20 engine modifications

1.M20B20 (1977 - 1981 onwards) - the first version of the engine with carburetor system fuel supply. Compression ratio 9.2, power 120 HP at 6000 rpm, torque 160 Nm at 4000 rpm.
2.M20B20 (1981 - 1987 onwards) - version with electronic multipoint injection L-Jetronic, compression ratio 9.8, power 125 hp at 5800 rpm, torque 170 Nm at 4000 rpm.
3.M20B20 (1982 - 1984 onwards) - modification with mechanical multipoint injection K-Jetronic, compression ratio 9.9, power 126 hp. at 5800 rpm, torque 170 Nm at 4000 rpm.
4.M20B20 (1985 - 1991 onwards) - engine with electronic direct injection LE-Jetronic, compression ratio 9.8, power 129 hp at 6000 rpm, torque 174 Nm at 4000 rpm.
5.M20B20 (1987 - 1992 onwards) - version with electronic direct injection Motronic, compression ratio 8.8, power 129 hp. at 5800 rpm, torque 174 Nm at 4300 rpm.

BMW M20B20 engine problems and malfunctions

The cons and malfunctions of the M20B20 engine are completely similar to the older 2.5-liter brother of the M20B25, you can learn about them. Among other things, if we are talking about the BMW five, this power unit it is also too weak, so for the E34 it is better to buy the M50B25 engine.

BMW M20B20 engine tuning

M20B20 Stroker

Over the long years of the existence of the M20 series, many options have been developed to increase the displacement of the M20B20. The simplest and most effective option is a stroker up to 2.3 L, since the height of the cylinder block of both engines is the same. To convert an M20B20 into an M20B23, it is enough to buy a crankshaft, pistons, connecting rods and a flywheel from M20B23, a new cylinder head gasket, bolts, liners and rings. By building such an engine, you will get approximately 150 hp.
An interesting option is the conversion of M20B20 into M20B25, but we will go further and increase the displacement from 2.0 L to 2.8 L. For these purposes, we need to bore the cylinders to 84 mm, buy an M52B28 crankshaft, leave the connecting rods stock, M20B25 Kat pistons (cut by 3 mm ), flywheel M20B20 Carb. Plus, replace the radiator, the standard one will not cope. As a result, we get a more powerful M20B28.
Then everything is like : shafts, porting, inlet, outlet ...
You need to understand that when the cylinders are bored up to 84 mm, the walls of the block will become very thin and the engine resource will be significantly reduced. Such motors travel about 10,000-20,000 km.

M20B20 Turbo

The construction of a turbo M20 on the weakest engine of the series is a dubious decision, but it has the right to life. To implement the project, you need to buy a turbo kit based on a Garrett T04E or Garrett GT30 turbine, with a turbo manifold, blow-off, intercooler, piping, with oil supply and oil drain, oil cooler, boost controller, wastegate, downpipe and 2.5 ”full exhaust. In addition, it is necessary to replace pistons and connecting rods with forged ones, compression ratio ~ 8.5, and also buy a metal cylinder head gasket. Added to this are 440 cc nozzles, fuel pump Walbro 255 lph, boost pressure sensor, oxygen sensor, oil pressure sensor, temperature sensor exhaust gases, ECU Megasquirt.
When building such a turbo project on the M20B28 Stroker, the engine power will be about 350-400 hp.

Engine

Four-cylinder carburetor engine M-20 is economical to operate and very durable.

The engine cylinders are cast from gray cast iron in one block with the upper part of the crankcase and are arranged vertically in a row. Liners made of acid-resistant wear-resistant cast iron are pressed into the cylinders for the entire length of the rings stroke. These liners increase the service life of the cylinders before bore by 2.5-3 times. The wall thickness of the sleeves is 2 mm.
The water jacket of the block is made over the entire height of the cylinders. Saddles exhaust valves pressed into the block; they are made of a special high-hardness heat-resistant alloy. Machining these seats is only possible by grinding. The inlet valve seats are made directly in the body of the block.
At the bottom of the cylinder block there are four beds for the main bearing shells crankshaft.
The cylinder head is removable, common to all cylinders, cast from an aluminum alloy. The use of an aluminum alloy with high thermal conductivity, as well as the proper shape of the combustion chamber, ensures that the engine operates without detonation at a relatively high compression ratio and moderate octane number fuel.
The cylinder head is attached to the block with 23 pins. Flat washers are placed under the head fastening nuts. The order in which these nuts are tightened is very important. Tightening the nuts should be done in sequence in two steps, first preliminary and then finally. It is recommended to use a torque wrench to control the tightening force. The torque should be within 6.7-7.2 kgm. In the absence of a torque wrench, tighten the nuts with an ordinary spanner wrench from the driver's tool kit with one hand without jerking, in order to avoid breaking the studs or deforming the cylinders.
It is imperative to tighten the nuts on a cold engine, since the coefficient of linear expansion of steel studs is much less than that of an aluminum head, therefore, tightening on a hot engine will be completely insufficient after it cools down.
The connection of the cylinder head to the block is sealed with a gasket made of steel asbestos cloth impregnated with fit. The combustion chamber windows and water passages in the gasket are edged with sheet metal. The thickness of the compressed gasket is approximately 1.5 mm.
Before putting the gasket in place, it should be additionally rubbed on both sides with graphite powder to prevent adhesion of asbestos to the block or to the head.

Pistons, made of aluminum alloy, have flat bottoms and elliptical skirts (value of ellipticity 0.29 mm). To make the piston springy, a U-shaped notch is made on its skirt. The major axis of the ellipse of the piston skirt is perpendicular to the axis of the piston pin. Therefore, in the engine, the clearance between the piston and the cylinder in the direction in which lateral forces from the connecting rod act on the piston (perpendicular to the crankshaft axis) is significantly less than in the direction in which there are no lateral forces (parallel to the crankshaft axis).
During engine operation, the piston expands from heating more in the direction of the axis of the piston pin than in the direction perpendicular to it; In this case, the ellipticity of the piston decreases, and its shape approaches round. This property of the piston is obtained due to the distribution of its material and due to the U-shaped notch on the skirt. This property makes it possible to reduce the clearance between the cylinder and the piston in the direction of the action of lateral forces and ensure, on the one hand, the operation of cold engines without knocking the pistons, and on the other hand, a decrease in friction between the piston and the cylinder, which prevents the formation of scoring on the pistons during engine operation with full load. In the cylinder, the piston is installed so that the U-shaped notch is facing away from the valve box.
There are 5 annular grooves on the piston head. The upper, narrowest groove traps heat from the piston crown and thereby reduces heating of the upper compression ring, preventing it from burning. In the next two grooves, the compression rings are placed and in the last two (widest) - oil scraper rings.
In the grooves for the oil scraper rings, holes are drilled through which the lubricant removed by the rings from the cylinder walls enters the inner cavity of the piston and then flows into the crankcase. In the middle of the piston there are bore bores for the piston pin. In the lower part of the piston skirt under the bosses, 2 lugs are made, by cutting off which the pistons are adjusted by weight at the factory. To improve the running-in of the piston-cylinder pair, the pistons are plated with tin.
Piston rings are made of gray cast iron. Each ring is made from a separate casting to ensure proper material structure.
The compression rings on the inner surface are chamfered, causing some distortion of the ring in its groove. As a result of this skewing, the ring does not adhere to the cylinder with its entire surface, but only with its lower edge, which improves and accelerates the running-in of the ring. When installing the rings on the piston, their chamfers should be facing up, towards the bottom.
Compression rings are the same size. The upper compression ring, which is closer than the other rings to the combustion chamber and therefore works in a very difficult conditions, coated with porous chromium, which sharply increases its durability. Increasing the durability of the upper compression ring, which protects the remaining rings from the effects of combustion products, increases the durability of all rings, as well as the cylinder bore.
Both oil scraper rings are the same, they have slots in the middle for oil drainage. All rings have straight locks. The second compression ring and both oil scraper rings are tinned for better running-in to the cylinders.
Piston pins floating type, steel, hollow. The outer surface of the fingers is hardened by currents high frequency... The pins are held against axial movements by two flat snap rings installed in the grooves of the piston bosses. Removal and installation of retaining rings should be done with pliers.
Connecting rods I-section steel forged. Bronze bushings are pressed into the upper heads of the connecting rods. A rectangular cutout is made in the upper head to lubricate the finger.
The lower head of the connecting rod is split, with a cover. The cover is fastened with two bolts and nuts, cotter pins separately. At the upper end of the connecting rod, above its small head and on the cover of the lower head, there are massive bosses, when cut off at the factory, the total weight of the connecting rod and the distribution of weight between the heads are adjusted. In a set for one engine, the difference in weight of the connecting rods is allowed within 8 g.
In the lower heads of the connecting rods, interchangeable thin-walled bushings are installed, made of steel tape filled with lead-telluride babbit of the BST brand. The inserts are held in the head by means of bent tendrils entering the slots on the connecting rod and on the cover.
The connecting rods of the M-20 engine, despite the same basic dimensions, are not interchangeable with the connecting rods of the GAZ-51 engine. The connecting rods of the M-20 engine have symmetrical lower heads, and the connecting rods of the GAZ-5 engine are asymmetrical. To distinguish on the M-20 connecting rods, a round protrusion is made.
Crankshaft four-bearing, steel, forged, statically and dynamically balanced, equipped with counterweights to relieve the main bearings from inertial forces. The shaft journals are surface hardened to a depth of 3-5 mm to increase wear resistance. Grease from the main bearings to the connecting rod is supplied through channels drilled in the shaft body.
The main bearing caps fit tightly into the groove on the block, which keeps them from lateral movements; They are fastened with bolts screwed into the body of the block. The bolts securing the first three covers (counting from the front) are pinned in pairs with wire, and the rear cover fastening bolts are locked by bending the antennae of the plate placed under them.
The main bearing shells are interchangeable, the same type as the connecting rod, but made of a thicker tape. The upper main bearing shells differ from the corresponding lower ones in the shape of the oil grooves and oil holes.
Axial movement of the shaft is limited by a thrust bearing consisting of two washers located on either side of the front main bearing. Washers are made from steel tape cast with babbitt.

BMW M20 engine- six-cylinder piston engine with one top camshaft, which was produced between 1977 and 1993.

BMW M20 engine is also known as M60 and has 12 valves that are driven by a timing belt. It was originally produced with a carburetor, and over time it was equipped with a fuel injection system - Bosch.

BMW M20B20 engine

The first model to use this engine was the E12 520/6. Fuel was supplied by the Solex carburetor, and since 1982, the Bosch L-Jetronic fuel injection system has been used for the first time on the B20 engine. In 1987 BMW motor The M20 was revised again and a control system was added Bosch engine Motronic and catalytic converter.

Problems and malfunctions of the M20 motor

cracks in the cylinder head in the area of 4 and 5 cylinders near the coolant channel;
valve damage: the reason is a break in the timing belt, since the timing belt resource is 60,000 km;
severe wear of the transmission of the gas distribution mechanism: the reason is a violation of the angular tension roller;

It was not for nothing that the GAZ M20 passenger car was called "Victory" - it really was a victory in all respects. The Great Patriotic War was won, and it became possible to raise the country's industry to a high level. AND new car became a symbol of that era.

This is how one of the first models of the GAZ-20 Pobeda car looks like

The creation of a new car model proved that in the industry Soviet Union there is a huge potential and the country can produce products that are not inferior in their characteristics to those of well-known Western manufacturers. Considering that the production of GAZ M 20 began almost immediately after the end of the war, then for our country such an event can be considered a great achievement.

The development of a new model of the GAZ passenger car began in the pre-war years. Then there were many design ideas - at the same time, a new project was being conceived, the development of a 6-cylinder GAZ 11 engine was in full swing. But the designers began to design a middle-class passenger car in 1943.

The first modification of the Victory

It was at this time that the basic units and assemblies were determined, the shapes of the future body were designated. The model had its own characteristic differences from the previous brand:

More low level gender compared to its predecessor;
Engine location above the front suspension beam;
The presence of a hydraulic drive in the brake system;
Improved independent front suspension;
Higher efficiency motor;
Streamlined body with "licked" wings;
Improved interior design.

initially new model was considered in two versions, depending on the engine, each of them was assigned its own index:

With a 6-cylinder engine - M-25;
With a 4-cylinder engine - M-20.

This is what the M-20 engine looks like in a cut.

Almost immediately after the end of the war, "Victory" underwent lengthy tests, and after their successful completion was submitted for consideration to the highest party government.

The project was approved, and it was decided to launch a more economical version, the M-20 brand, into mass production. In the future, this name was stuck with the car.

In the development stage of the car, the name "Homeland" was also considered. But Stalin did not approve of this option. When it came to selling a car, it turned out that they were selling the Motherland. The production of the GAZ Pobeda car began at the end of June 1946. Despite successful tests, many different design flaws and imperfections were revealed in the car. Therefore, over the next six months, only 23 cars rolled off the assembly line, and mass assembly at the Gorky Automobile Plant began only in the spring of 1947.

The interior of the car "Pobeda" GAZ 20

Already in February 1948, GAZ assembled 1,000 units of the new model, and by the beginning of autumn another 700 Pobeda vehicles had appeared.

Design features of "Victory"

The prototype of the GAZ M 20 is to some extent the Opel Kapitan, at least a lot of design decisions are taken from this car. But our own design solutions made Pobeda unique:

The front and rear fenders practically merged with the body, which was an innovation in those days;
The hinges of all four doors were attached to the front of the pillars and the doors opened in the direction of the car;
There were no decorative footrests.

The chief designer of the GAZ Pobeda project was AA Lipgart. The design group included engineers: Krieger, Kirsanov and Kirillov. The first of the listed was the deputy chief designer, the second led the group. Kirsanov was engaged in the development of the body. The unique look of the car was created thanks to the artist Samoilov, but Samoilov his project in the form real car I never saw - the artist died tragically in 1944. The very first sketches were created by the artist Brodsky in 1943.

For "Victory", the body and body elements for the first time became parts of their own, domestic production... Prior to that, other car brands received parts from foreign firms, in particular, they ordered production from American manufacturers.

Engine

Since the 6-cylinder GAZ 11 engine did not go into production, the main engine for the GAZ M20 was the 4-cylinder GAZ 20. The new power unit had the following differences from the GAZ 11 engine:

The compression ratio in the cylinders was only 5.6, but such a low figure made it possible to work on low-octane 66th gasoline. In the post-war years, there were problems with fuel in the country, and the use of such a brand of gasoline made it possible to somehow get out of the situation. But the engine thrust was weak, and the engine could hardly cope with its duties, even in a passenger car.

Gearbox and rear axle

The gearbox had three speeds forward and a gear reverse... There were no synchronizers in it, the gearshift lever had a floor arrangement. This box was borrowed from the GAZ M1 model. In the early 50s of the codes of the last century, the gearbox lever was moved to steering column, and the checkpoint was taken from the ZIM car. It already provided for synchronizers in second and third gear.

The rear axle was not borrowed from other car models; it was designed specifically for the GAZ M 20 brand.

It looks like a gearbox for Victory gas 20

On main gear there was a pair of spiral-conical type. The inconvenience of the design is that in order to dismantle the axle shafts, it was necessary to completely disassemble the main gear housing.

Features of the body and interior

During the post-war years, the bodywork was considered to be made at a high level, which was repeatedly noted by foreign experts in the automotive business. The body had a thick layer of metal (1 to 2 mm). Thicker was the metal on the side members and in places where the body was reinforced. The body type was classified as a "convertible".

The salon had a modern layout for its time, it was attended by:

There were others useful little things, such as illumination of the luggage compartment and engine compartment, or a cigarette lighter in the salon console. In later versions of Pobeda, heating was provided in the heating system windshield and also late car began to be completed with a regular radio receiver.

Separate seats, which stand in modern cars, on "Pobeda" was not. In total, two sofas were installed in the car: front and rear. At that time, velor was not used, the seats were trimmed with high-quality woolen fabric. Front seat had adjustments and could move back and forth. In cars intended for taxis, sofas were covered with leatherette.

Front and rear suspension, braking system

The schematic diagram of the front suspension was later used on all Volga models. It was of the pivot type, independent, provided for the presence of threaded bushings. Some parts were borrowed from the Opel Kapitan model (shock absorbers, threaded bushings), but the pivot device had own development... The hydraulic shock absorbers were of the lever type, that is, they simultaneously served as the upper suspension arms. The exact same design was present in rear suspension, rear axle mounted on springs.

The GAZ M 20 brake system was considered the most advanced in the middle of the twentieth century, for the first time it became hydraulic for the entire time of the Soviet automotive industry.

But there was only one circuit in the system, and there could be no question of any division. That is, if any of the 4 working cylinders began to leak, the brakes disappeared altogether. In all Volga models with drum brakes, two working cylinders were installed per wheel.

Construction diagram drum brakes Victory

On "Victory" on both suspensions there was one cylinder, each cylinder spread two pads at the same time.

Electrical part

The electrical equipment of "Victory" was also distinguished by its modernity, it used the most advanced technologies of the post-war years. Of the features of the electrical part, it can be noted:

The instrument cluster in the cabin had all the necessary set of sensors that informed the driver about the state of the car and the speed of movement:

Speedometer;
Fuel level sensor;
Oil pressure sensor;
Water temperature indicator;
Ammeter;
Watch.

The panel also had two direction indicator lamps. The dashboard itself was made of steel and painted to match the body color, plastic trims adorned it and gave it elegance.