Absolutely everyone has heard of such a brand as BMW. A rather capacious history of this company deserves respect from motorists. The corporation has been and remains a leader in the automotive industry. The quality and level of development of its products are measured by many machine manufacturers.

Features of the German-made M20 engine

In the first half of the 20th century, the company's engineers were actively engaged in fine-tuning in-line units. One of the successful designs was the 6-cylinder M20 engine from BMW, which became the starting point for subsequent units.

"Twenty" has taken root well in the model ranges of the third and fifth series, as evidenced by the presence of this installation in:

• E12 (1972 - 1981);
• E21 (1977 - 1983);
• E28 (1982 - 1987);
• E34 (1987 - 1990).

Stable operation is provided by 12 valves receiving commands from a rotating camshaft. The layout of the cylinder head is organized according to the SOHC type. The power plant was produced in 4 types:

• M20B20;
• M20B23;
• M20B25;
• M20B27.

The number after the letter B indicates the volume of the product. Owners of old "triples" talk about frequently occurring malfunctions of this kind:

• the formation of a crack in the cylinder head (often between 4 and 5 cylinders) connecting the cooling and crankcase cavities;
• valve damage when the timing belt breaks;
• violation of the position of the tension roller, which causes severe wear of the timing gear.

Reliability above all: the M50 engine from the German concern BMW

The employees of the company did not stop there. The desire to increase dynamics and at the same time not change the overall configuration of the unit resulted in the creation of a new generation engine marked M50.

Key Features:

• four valves per cylinder;
• two camshafts (this made it possible to somewhat disconnect the connection between the intake and exhaust);
• timing chain drive.

This power plant replaced the M20 on the conveyor of the plant, the performance of which at the beginning of the 90s was far from ideal. Two years later, the "fifty" was equipped with a proprietary know-how - an active variable valve timing system VANOS.

At the command emanating from the ECU, with the help of a fluid coupling, the intake camshaft was rotated to a certain angle. As a result of the modernization, the operation of the motor has become effective throughout the entire range of rotation of the crankshaft.

The innovative in-line six-cylinder M50 engine had the following modifications:

• M50B20;
• M50B20TU VANOS;
• M50B25;
• M50B25TU VANOS.

The reliability and durability of this series has been repeatedly noted by many fans of the Bavarian car industry. Malfunctions often occur as a result of unskilled repairs. With high mileage, there were burnouts of the intake valves. Prolonged overheating leads to cracks in the cylinder head.

In pursuit of efficiency: M54 engine under the BMW brand

The corporation decided to celebrate the beginning of the 21st century with a new six-cylinder in-line engine. The motor received such innovations:

• cylinder block cast from aluminum alloy with cast iron inserts;
• Double VANOS system (a breakthrough in the filling compared to the M52);
• optimized oil ring design.

When creating this product, engineers stepped even further, forcing both camshafts to obey the computer. As a result, better throttle response and excellent traction at any speed.

The reliability of BMW M54 engines in E36, E39, E46 bodies has suffered somewhat. Owners note the following problems:

• failure of camshaft position sensors;
• tendency to coking due to the small thickness of the piston rings;
• unstable operation of a cold engine (misfire);
• blown exhaust valves.

M40 four-cylinder engine and BMW's desire for economy

To replace the obsolete M10 in the late 80s, a new line-up for four rubbing pairs (cylinder-piston) came. From the category of new technologies, the M40 got hydraulic lifters and an aluminum cylinder head housing. The chain drive was also replaced with a belt drive. This made it possible to reduce the tone of the power unit.

The series included two modifications:

• M40B16;
• M40B18.

The fuel supply process began to obey electronics thanks to the Bosch M1.3 injection power system. The operational features of the unit are as follows:

• increased sensitivity to the condition of the belts (they are quite thin here);
• rapid wear of a pair of rocker cams due to the instability of the camshaft lubrication process;
• capricious nozzles provoke the occurrence of failures when the car is moving;
• instability of idling (there is a high probability of suction and jamming of the throttle).

The history of the development of the potential of BMW vehicles reflects the constant progress in dynamics and power. Painstaking attention to detail and a high level of ingenuity of the staff contributed to the creation of innovative in-line engines discussed above.

Engine

The M-20 four-cylinder carburetor engine is economical in operation and very wear-resistant.

The engine cylinders are cast from gray iron in one block with the upper part of the crankcase and are arranged vertically in a row. Sleeves made of acid-resistant wear-resistant cast iron are pressed into the cylinders for the entire length of the ring travel. These sleeves increase the service life of cylinders before boring by 2.5-3 times. The wall thickness of the sleeves is 2 mm.
The water jacket of the block is made at the entire height of the cylinders. The exhaust valve seats are pressed into the block; they are made of a special heat-resistant alloy of high hardness. These saddles can only be machined by grinding. The inlet valve seats are made directly in the body of the block.
In the lower part of the cylinder block there are four beds for the crankshaft main bearing shells.
The cylinder head is removable, common to all cylinders, cast from 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 runs without detonation at a relatively high compression ratio and a moderate octane rating of the fuel.
The cylinder head is attached to the block with 23 studs. Flat washers are placed under the head mounting 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 that controls the tightening force. The torque should be in the range of 6.7-7.2 kgm. In the absence of a torque wrench, the nuts are tightened with a conventional 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, so a tightening made on a hot engine will be completely insufficient after it cools down.
The connection of the cylinder head with the block is sealed with a gasket made of steel-asbestos cloth impregnated with fit. The windows of the combustion chambers and the holes for the passage of water in the gasket are edged with sheet metal. The thickness of the compressed spacer is approximately 1.5 mm.
Before putting the gasket in place, it should be additionally rubbed on both sides with graphite powder to prevent asbestos from adhering to the block or head.

Pistons, made of aluminum alloy, have flat bottoms and elliptical skirts (ellipticity value 0.29 mm). To give the piston spring properties, a U-shaped cut 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 the lateral forces from the connecting rod act on the piston (perpendicular to the axis of the crankshaft) is significantly less than in the direction in which there are no lateral forces (parallel to the axis of the crankshaft).
During engine operation, the piston from heating expands more in the direction of the axis of the piston pin than in the direction perpendicular to it; the ellipticity of the piston thus 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 cut on the skirt. This property makes it possible to reduce the gap between the cylinder and the piston in the direction of lateral forces and ensure, on the one hand, the operation of cold engines without piston knocking, and on the other hand, a decrease in friction between the piston and the cylinder, which prevents the formation of scuffing on the pistons during engine operation at full load. In the cylinder, the piston is installed so that the U-shaped slot faces the opposite side of the valve box.
The piston head has 5 annular grooves. The top, narrowest groove retards the spread of heat from the bottom of the piston and thereby reduces the heating of the upper compression ring, preventing it from burning. Compression rings are placed in the next two grooves and in the last two (widest) - oil scraper rings.
Holes are drilled in the grooves for the oil scraper rings, through which the lubricant removed by the rings from the cylinder walls enters the internal cavity of the piston, and then flows into the crankcase. In the middle part of the piston there are bosses with holes 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 tin-plated.
Piston rings made of gray cast iron. Each ring is made from a separate casting, which ensures the proper structure of the material.
Compression rings on the inner surface have a chamfer, causing some distortion of the ring in its groove. As a result of this misalignment, the ring does not adjoin 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 turned up towards the bottom.
The compression rings are the same size. The top compression ring, located closer to the combustion chamber than the other rings and therefore working in very difficult conditions, is covered with porous chrome, which dramatically increases its durability. Increasing the resistance of the upper compression ring, which protects the remaining rings from the effects of combustion products, increases the resistance of all rings, as well as the cylinder mirror.
Both oil scraper rings are the same, they have slots in the middle part to drain the oil. Locks on all rings are straight. The second compression 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 high frequency currents. From axial movements, the fingers are kept by two flat spring retaining rings installed in the grooves of the piston bosses. Removal and installation of retaining rings should be done with round-nose pliers.
connecting rods I-section forged steel. Bronze bushings are pressed into the upper heads of the connecting rods. For finger lubrication, a rectangular cutout is made in the upper head.
The lower head of the connecting rod is detachable, with a cover. The cover is fastened with two bolts and nuts, cottered 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 weight distribution between the heads are adjusted. In a set for one engine, the difference in the weight of the connecting rods is allowed within 8 g.
Interchangeable thin-walled liners are installed in the lower heads of the connecting rods, made of steel tape, filled with BST grade lead-telluride babbitt. The liners are held in the head with the help of bent antennae included in 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. For distinction, a round protrusion is made on the M-20 connecting rods.
Crankshaft four-bearing, steel, forged, statically and dynamically balanced, equipped with counterweights to unload the main bearings from the action of inertial forces. Shaft journals are surface hardened to a depth of 3-5 mm to increase wear resistance. Lubrication from the main bearings to the connecting rod is supplied through channels drilled in the body of the shaft.
The main bearing caps fit tightly into the groove on the block, which keeps them from lateral movement; they are fastened with bolts screwed into the body of the block. The bolts fastening the first three covers (counting from the front) are cottered in pairs with wire, and the bolts for fastening the rear cover 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 shells of the main bearings differ from the corresponding lower ones in the shape of the oil grooves and holes for supplying oil.
The axial movement of the shaft is limited by a thrust bearing consisting of two washers located on both sides of the front main bearing. The washers are made from steel tape filled with babbitt.

BMW M20B20 engine

Characteristics of the M20V20 engine

Production	Munich Plant
Engine brand	M20
Release years	1977-1992
Block material	cast iron
Supply system	carburetor/injector
Type	in-line
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 volume, cc	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 regulations	-
Engine weight, kg	~113 (dry)
Fuel consumption, l/100 km (for E30 320i) - city - track - mixed.	13.0 7.5 9.5
Oil consumption, g/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
Operating temperature of the engine, hail.	~90
Engine resource, thousand km - according to the plant - on practice	- ~250-300
Tuning, HP - potential - no loss of resource	400+ n.a.
The engine was installed

Reliability, problems and repair of the BMW M20B20 engine

The inline six-cylinder BMW M20B20 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 working volume of 2.7 liters. The M20B20 motor was used on cars with the 20i index.
The engine is based on a cast-iron cylinder block, on top is an aluminum 12-valve cylinder head with a single SOHC 12V camshaft. At first, a head known as 200 was used, later it was replaced by 731, which was distinguished by a large diameter inlet ports. The diameter of the intake valves is 40 mm, exhaust 34 mm. There are no hydraulic lifters, valve adjustment is required every 10-20 thousand km, valve clearances inlet 0.25 mm, outlet 0.3 mm. The timing drive uses a belt, the replacement of which is required every 50 thousand km, when the belt breaks, the engine bends the valve.
The power supply 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 a new engine -.

BMW M20B20 engine modifications

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

Problems and disadvantages of BMW M20B20 engines

The cons and malfunctions of the M20B20 engine are completely similar to the older 2.5-liter counterpart M20B25, you can find out about them. Among other things, if we are talking about the BMW five, this power unit 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 working volume 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 M20B20 to M20B23, it is enough to buy a crankshaft, pistons, connecting rods and 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 to convert the M20B20 to 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), M20B20 Carb flywheel. 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 boring cylinders up to 84 mm, the block walls will become very thin and the engine life will be significantly reduced. Similar motors drive about 10,000-20,000 km.

M20B20 Turbo

The construction of the M20 turbo 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, oil supply and oil drain, oil cooler, boost controller, wastegate, downpipe and a full 2.5” exhaust. In addition, it is necessary to replace the pistons and connecting rods with forged ones, the compression ratio is ~ 8.5, and also buy a metal cylinder head gasket. Added to this are 440 cc injectors, Walbro 255 lph fuel pump, boost pressure sensor, oxygen sensor, oil pressure sensor, exhaust gas temperature sensor, Megasquirt ECU.
When building such a turbo project on the M20B28 Stroker, the engine power will be about 350-400 hp.

BMW M20 engine- a six-cylinder piston engine with a single overhead camshaft, which was produced from 1977 to 1993.

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

BMW M20B20 engine

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

Problems and malfunctions of the M20 motor

• cracks in the cylinder head in the region of 4 and 5 cylinders near the coolant channel;
• valve damage: the cause is a broken 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;

Spare part requestViber 89639932224

Engine BMW М20B20 2.0i 206KA

The M20 engines were first introduced to the general public in 1977 and were, in fact, a modification of the M30 power units, which has a much smaller displacement. They were created primarily in order to provide the very first car of the fifth series (E12) with an inexpensive, economical and modern engine. They were also used to equip machines of the third series, since there was simply not enough space for them for the M30. M20 is an in-line power unit with 6 cylinders and 12 valves in its design, as well as a timing belt drive. Its cylinder block is made of cast iron, but is equipped with an aluminum head. Interestingly, until 1982, this engine was produced under the M60 marking, which in 1983 was assigned to a completely different motor of the Bavarian company. The cost is 35,000 rubles.

Engine Specifications M20B20 (206KA)

Engine model: M20B20 (206KA)

Volume: 1990 cm3

Power: 129 HP

Number of cylinders: 6

In total, there are four modifications of the M20 power unit: M20V20, M20V23, M20V25, M20V27. Between themselves, they differ in volume (from 2.0 to 2.7 liters), power and some design features. A distinctive feature of these engines is the absence of a fuel pump in the cylinder block, as well as the use of various types of gas distribution mechanisms. In addition, there are modifications of the M20 power units with different intake valves (both in size and geometric configuration). It should also be taken into account that the M20V27 engine was heavily derated by the designers, although it has a high torque.

At our disassembly you can buy such