BMW M50 engine description characteristics diagnostics tuning photo video. Description and characteristics of the BMW M50 engine VANOS control

The BMW M50 engine is available in two versions, with a volume of 2.0 and 2.5 liters and was produced at the Steyer plant. Until 1996, a total of 943 795 engines were produced.

BMW M50 from M20 differs in many design features, including lower CO2 emissions and fuel consumption, higher efficiency and power, as well as stability and performance.

The main difference compared to the M20 is the 24-valve cylinder head and two overhead camshafts (DOHC), which are driven by two timing chains (the timing belt in the M20), the tappets are low maintenance, the hydraulic compensator, all parts of the ignition system are under plastic cap on the valve cover, forged connecting rods (C45), lightweight pistons, high compression ratio, full sequential fuel injection, intake manifold has completely smooth interior walls and is 50% lighter than the M20 aluminum intake manifold.

Based on the M50 motor, it was created, which was installed on.

In order to achieve the set goals of performance indicators, the M50 engine has been completely developed new head DOCH cylinder block (with two overhead camshafts) with 4-valve technology, the feature of which is low gas exchange rate, ideal spark plug position and a decrease in the movable mass of each valve.

BMW M50B20 engine

This version of the power unit was installed on,

BMW M50B24 engine

2.4 liter variant BMW motor M50 with a volume of 2.4 liters (2394 cc) which was produced for cars 3 and 5 series of Thai specification. Its maximum power is 188 hp. (138 kW) at 5900 rpm, and the torque is 235 Nm at 4700 rpm. The piston diameter is 84 mm and the piston stroke is 72 mm.

BMW M50B25 engine

BMW M50 engine characteristics

		M50B20	M50B25
engine's type		inline 6-cylinder
mounting position	in front	30º to the outlet side
	sideways	2.28º back
effective engine displacement	dm³	1990	2494
piston stroke	mm	66	75
cylinder diameter	mm	80	84
		0,825	0,893
power	kW / hp	110/150	140/190
at rotational speed	rpm	5900	5900
torque	Nm	190	245
at rotational speed	rpm	4700	4700
specific power	kW / dm³	55,3	56,1
compression ratio	:1	10,5	10,0
the order of operation of the cylinders		1-5-3-6-2-4
maximum piston speed	m / s	14,3	16,25
valve diameter	mm
inlet		30	33
release		27	30,5
valve stroke	mm
inlet / outlet		9,7/8,8	9,7/8,8
flow area	vp / issue	240º / 228º	240º / 228º
valve opening angle	vp / issue	96º / 104º	101º / 101º
fuel		high octane unleaded gasoline

Engine structure

BMW M50 engine structure / mechanics

M50 engine: 1 - Oil pump; 2 - Drive belt; 3 - coolant pump; 4 - Thermostat; 5 - Oil filter; 6 - Chains; 7 - Inlet
collector; 8 - Plugs and ignition coils; 9 - Camshafts; 10 - Hydraulic pusher;

Carter / crank mechanism

Peculiarity:

• new development - torsionally rigid crankcase, optimized by weight;
• distance between cylinders: 91 mm, cylinder diameter (2.0 liters): 80 mm, cylinder diameter (2.5 liters): 84 mm;
• crankshaft made of nodular cast iron on 7 main bearings with 12 counterweights;
• cast flywheel;
• torsional vibration damper with integrated incremental gearing;

Cylinder block technical parameters, mm:

M50 engine crankcase block: 1 - Cylinder block with pistons; 2 - Hexagon bolt M10X75; 3 - Oil nozzle; 4 - Plug D = 12.0MM; 5 - Bolt of the bearing cover; 6 - Oil nozzle; 7 - Cover D = 45MM; 8 - Threaded plug; 9 - O-ring; 10 - Centering sleeve D = 13.5MM; 11 - Centering sleeve D = 10.5MM; 12 - Centering sleeve D = 14.5MM; 13 - Seal. asbestos-free block crankcase kit;

Crankshaft with bearing shells of the engine M50: 1 - Revolving crankshaft with bearing shells; 2 and 3 - Thrust bearing shells; 4, 5, 6 and 7 - bearing shell;

Pistons

The M50 engine is equipped with aluminum pistons with thermostatic inserts. In the piston crown there are four valve pockets, two each for the intake and exhaust valves.

The piston crown of a 2.5-liter engine additionally has a segmented recess (there is no segment recess in a 2-liter engine). The piston crowns are spray-cooled with oil. The sprinklers are located in the crankcase in the area of ​​the main bearings crankshaft.

The piston of the M50 motor: 1 - Piston; 2 - the piston pin; 3 - a spring retaining ring; 4 - Repair kit of piston rings;

Piston of the M50 engine: on the left side is the piston of a 2.0-liter engine, on the right - a 2.5-liter power unit;

Piston rings:

• upper compression ring: cylindrical ring plated with chrome, height 1.5mm
• lower compression ring: tapered ring with a groove on the working surface, 1.75 mm high
• oil scraper ring: so-called slotted box-type with a coil spring expander, 3 mm high

Camshaft drive

The drive is carried out by two single-row roller chains:

• Main drive (primary circuit):
  • from the crankshaft to the exhaust camshaft with a guide bar on the driven chain
  • hydraulically damped tension bar
• Auxiliary drive (secondary circuit):
  • from exhaust to intake camshaft
  • guide bar and hydraulically damped tensioner

Both chains are sprayed with oil where they leave the sprockets. The primary drive chain is supplied with a sprinkler located above the first crankshaft main bearing. The secondary drive chain is supplied with a spray gun in the upper chain tensioner housing.

The valves are driven by two semi-bearing overhead, cast hollow camshafts.

Camshafts and poppet followers are assembled with bearing housing for easy maintenance.

The head of the block of cylinders of the M50 engine: 1 - the head of the block of cylinders with support strips; 2 - Support bar, outlet side; 3 - Centering sleeve D = 9.5MM; 4 - Hex nut with washer; 5 - the guide sleeve of the valve; 6 - the inlet valve seat ring; 7 - Exhaust valve seat ring; 8 - Centering sleeve D = 9.5MM; 9 - Dowel pin M7X95; 10 - Dowel pin M7 / 6X29.5; 11 - Dowel pin M7X42; 12 - Dowel pin M7X55; 13 - Dowel pin M6X30-ZN; 14 - Dowel pin M6X45; 15 - Dowel pin M6X35-ZN; 16 - Centering sleeve D = 8,5X9MM; 17 - Dowel pin M8X50; 18 - Centering sleeve D = 10.5MM; 19 - Cover D = 28MM; 20 - Screw plug M24X1.5; 21 - Screw plug M18X1.5; 22 - Screw plug M8X1; 23 - Screw plug M12X1.5; 24 - O-ring; 25 - Cover 22.0MM;

Valve seat characteristics

Parameter	Valve seat
	intake	graduation	intake	graduation
	M50V20		M50V25
Diameter bore hole saddles in the block head, mm:
nominal	34	28	34	31,5
1st repair	34,2	28,2	34,2	31,7
2nd repair	34,4	28,4	34,4	31,9
with tolerance, mm	0.00 to +0.025		0.00 to +0.025
Working chamfer angle, degrees	45	45	45	45
External correction angle	15	15	15	15
Internal correction angle	60	60	60	60
Working chamfer width, mm	1,40-1,90		1,40-1,90
Outside diameter, mm
nominal	34,1	28,1	31.6 (nominal 34.1)
1st repair	34,3	28,3	31.8 (1st repair 34.3)
2nd repair	34,5	28,5	32.0 (2nd repair 34.5)
with tolerance, mm	0.00 to -0.025		0.00 to -0.025
Saddle height, mm
nominal	7,3		7,3
1st repair	7,5		7,5
2nd repair	7,7		7,7
with tolerance, mm	0.00 to -0.01		0.00 to -0.01

Valves of the M50 engine

Options	Inlet valves		Exhaust valves
	M50B20	M50B25	M50B20	M50B25
Head diameter, mm	30,00	33,00	27,00	30,50
Head diameter tolerance, mm	0.0 to -0.016		0.0 to -0.016
Rod diameter, mm
nominal	6,975		6,975
1st repair	7,10		7,10
2nd repair	7,20		7,20
manufacturing tolerance	0.00 to -0.015		0.0 to -0.015
Clearance between guide bushings and valve stems	0,5		0,5

Guide bush parameters, mm
total length	43,5
Outside diameter:
nominal	12,5
1st rem. the size	12,6
2nd rem. the size	12,7
Manufacturing tolerance	+0.033 to +0.044
Inner diameter:
nominal	7,0
1st rem. the size	7,1
2nd rem. the size	7,2
Manufacturing tolerance	0.0 to +0.015
Diameter of holes for guide bushings:
nominal	12,5
1st rem. the size	12,6
2nd rem. the size	12,7
Manufacturing tolerance	0.00 to -0.018

Cylinder head

The cylinder head of the M50 engine with diametrically opposed inlet and outlet channels with

• four valves per cylinder
• two camshafts
• disc pushers with hydraulic gap adjustment (HVA)

The very small valve angles flatten the combustion chamber and concentrate the fuel mixture around the centrally located spark plug.

Sectional view of BMW M50 cylinder head

Hydraulic clearance and valve drive control

(HVA) integrated in the poppet follower. This reduces noise production and makes it easier Maintenance:

• No need to install and check valve drive clearance
• The valve timing is clearly observed for a long time

The hydraulic pusher is mainly composed of two moving parts, the pusher and the cylinder.

With the force of the spring, both parts are moved apart until there is no gap between the camshaft and the valve stem.

The non-return valve serves to fill and close the chamber high pressure.

Oil circulation

The oil is supplied via a duocentric pump with an internal rotor and an integrated oil pressure regulation system (similar to c).

The pump is located in the oil pan and bolted to the cylinder block. It is driven by a single-row roller chain directly from the crankshaft.

The oil filter is installed vertically on the intake side. The paper filter cartridge can be replaced from the top. To replace the filter, unscrew the central fixing bolt of the oil filter cover.

Sectional M50 Engine - Front View

Cooling system

The water pump is integrated in the chain case. The mechanical seal ring has a ceramic surface, the impeller is made of plastic, the body is made of aluminum.

The hot water is drawn off for heating from the cylinder head.

The crankcase and cylinder head are cooled primarily in the longitudinal direction. The main stream of water flows from front to back, rises through the connecting channels to the cylinder head and flows from back to front there.

Auxiliary units

The auxiliary units are driven by a maintenance-free V-belt.
The power steering pump and generator are located on the left in the direction of travel, the air conditioning compressor (SA) is on the right, close to the engine and mounted rigidly, not elastic.

Drive unit auxiliary units carried out on two levels:

• Level 1 (main drive):
  • crankshaft - water pump (fan) - generator - power steering pump or tandem pump, respectively (level control)
• Level 2 (additional drive):
  • crankshaft - air conditioning compressor

An external spring booster, a belt tensioner located on the driven belt strand, is hydraulically damped in one direction. Tension roller made of plastic.

Spark plug

A separate plastic deflection roller near the generator increases its wrap angle. In the ignition system of the M50 (RZV) engine, a spark plug is also used - an "F" plug with an SAE contact and a three-pointed side electrode.

The side electrode was developed by BMW in cooperation with suppliers especially for 4-valve engines. The combustion in these engines is tougher and faster and places higher demands on the spark plug.

The side electrode is welded to the candle body at three points (on 3 legs) and has the shape of a triangle relative to the central electrode.

The gap between the electrodes on a new plug is 0.9 mm +/- 0.1 mm. The candle has resistance< 1 кОм.

Ignition coil

Each spark plug has its own ignition coil. The coil is screwed onto the iron bag thus providing electrical contact with the ground.

The high voltage is supplied to the spark plug using a silicone funnel, a contact rod with an interference suppression resistor and a cone-shaped contact spring that presses against the SAE contact of the spark plug. This design provides the highest secondary voltage to the ignition system, since there are no high voltage wires and losses associated with voltage distribution.

Ignition coil of the M50 engine: 1 and 2- Ignition coil; 3 - the tip of the wire to the spark plug; 4 - Hex nut; 5 - Shield; 6 - a bolt with a hex head; 7 - Connector plug housing; 8 - Spark plug;

The ignition coil is electrically isolated, i.e. the end of the secondary winding is pulled out of the coil. It is designated "4A" and is the middle contact of the three-pole plug connection:

• on the primary side of terminals 1 and 15
• contact "4A"

Its contact tongue is longer. Thus, for safety reasons, when the plug is disconnected, this contact is disconnected last.

BMW M50TU engine

From September 1992 (PU92), the BMW M50 engine installed up to this point in the BMW E36 and E34 has been replaced by a revised version M50 TU(TU - Technically Reworked).

Feature of the BMW M50 TU engine

The technical redesign of the M50 motor has led to the following improvements:

• improved behavior of torque changes, especially in the medium speed range
• reduced fuel consumption
• improved idling performance while reducing idle speed
• improved exhaust characteristics (reduction of emission toxicity)
• improved throttle response
• best engine acoustics

Improvements to the M50TU (M50TU) engine relative to the M50 engine were achieved by the following design changes and measures:

• the use of digital motor electronics DME3.3.1 with anti-knock control in a 2.5-liter engine ( M50TUB25)
• application of the Siemens MS 40.1 engine controller in all E36 and E34 models with a motor M50TUB20
• increasing the compression ratio
• using the VANOS system
• changes in the crank mechanism (new pistons and connecting rods)
• a new idle speed regulator in a 2.5-liter M50TUB25 (ZWD-5) engine
• using a thermofilm air flow meter
• by reducing the diameter of the valve stem and using one valve spring
• the use of disc pushers and spring plates, optimized in terms of weight
• changes in valve acceleration characteristics
• by changing the crankshaft vibration damper

BMW M50 TU engine characteristics

technical specifications		M50TUB20	M50TUB25
engine's type		inline 6-cylinder
mounting position	in front	30º to the outlet side
	sideways	2.28º back
effective engine displacement	dm³	1990	2494
piston stroke	mm	66	75
cylinder diameter	mm	80	84
piston stroke / bore ratio		0,825	0,893
power	kW / hp	110/150	140/190
at rotational speed	rpm	5900	5900
torque	Nm	190	245
at rotational speed	rpm	4200	4200
specific power	kW / dm³	55,3	56,1
compression ratio	:1	11,0	10,5
the order of operation of the cylinders		1-5-3-6-2-4
maximum piston speed	m / s	14,3	16,25
valve diameter	mm
inlet		30	33
release		27	30,5
valve stroke	mm
inlet / outlet		9,0/9,0	9,0/9,0
flow area	vp / issue	228º / 228º	228º / 228º
valve opening angle	vp / issue	105-80º (VANOS / 105º)	110-85º (VANOS / 101º)
fuel		high-octane unleaded gasoline (Super)

The M50TUB25 was used on the E36 325i / 325is and E34 525i / 525ix.

VANOS system

How power characteristics and indicators exhaust gases and the behavior of the 4-stroke gasoline engine On the move, on the move can be greatly improved by the variable intake camshaft angle.

The opening angle of the intake camshaft of the M50TU engine can be changed, i.e. taking into account the specific operating conditions, switch from late opening to earlier or vice versa.

The advantages of the VANOS system:

• more power and improved torque in certain speed ranges
• reduced content of NOX and CH proportion of exhaust gases in the part-load range
• insignificant residual gas content at idle speed; due to this, on the one hand, an improved idle speed due to a more favorable mixture, and on the other hand, lower fuel consumption due to a decrease in the idle speed. Improved idle acoustics
• better engine response
• high functional safety
• extensive self-diagnosis and trouble-free troubleshooting

The VANOS shift system is controlled by the control unit of the corresponding digital motor electronics. In a 2-liter engine, a Siemens MS401 control unit, in a 2.5-liter engine, a Bosch M3.3.1 Motronic control unit.

VANOS design

Both for the M50TU20 engine and for the M50TU25 engine, many tests were carried out with various options camshafts and opening angles to identify in each case the most advantageous variable opening angles of the intake camshaft.

As a result, the following opening angles were chosen:

• M50TU20
  • 105º (late switching)
  • 80º (early switch)
• M50TU25
  • 110º (late switching)
  • 85º (early switch)

This results in a maximum switching angle of the variable intake camshaft opening angle of 25º KW (crankshaft angle) for both engine variants.

Components:

• inlet camshaft with a helical crown in front;
• chain sprocket with an internal helical rim;
• a hydraulic-mechanical device for changing the camshaft with one hydraulic piston and a helical gear;
• solenoid 4/2-way changeover valve;
• connecting oil pressure line from the cylinder block to the 4/2-way valve;
• control and diagnostic electronics of the controller;

Functioning of the VANOS system

The VANOS system in the M50 is controlled by the engine-specific digital electronics. The controller switches the 4/2-way valve by means of an electromagnet and thus acts by means of engine oil pressure on the hydraulic piston.

The hydraulic piston is held in one of two possible positions by mechanical stops and the oil pressure acting on it (black and white switching mode). There is a movable gear inside the hydraulic piston. This gear, by means of helical gearing, converts the translational movement of the piston into a rotation of the camshaft - relative to the drive sprocket.

The hydraulic piston with gear is mounted coaxially with the intake camshaft in a die-cast aluminum housing located on the front of the cylinder head.

The 4/2-way changeover valve is designed in such a way that when there is pressure in one chamber, there is no pressure in the other (backflow). When current is applied to the valve magnet, the piston moves through the armature against the force of the spring to the previous position. The helical spring provides reverse movement to the late position. Thus, in the event of a malfunction of the electromagnet or a failure of the control signal, the camshaft automatically returns to a late position.

With this emergency function, the engine can be started even if the VANOS system is faulty. If the camshaft is in an early position during start-up, the engine will not start.

VANOS system control

The solenoid valve of the VANOS system is controlled by a controller and depends on the coolant temperature, load and engine speed.

At the moment of switching the system for changing the angle of opening of the valves, the settings for the start of injection and ignition are changed.

To avoid frequent, repeated switching of the VANOS system, the control is carried out in the hysteresis mode.

Diagnostics M50TUB25 with DME M3.3.1

If there are no error messages in the memory, then the control signal is sent to the VANOS system when the M50TUB25 engine with DME M3.3.1 is operating at idle speed. For this, two adapters are used - special BMW tools No. 61 2 050 and 61 1 467. If, at the same time, close the solenoid valve to ground, an engine with a working VANOS system will work extremely unevenly or completely stall.

Diagnostics M50TUB20 with MS40.1

The VANOS system is fully tested with self-diagnostics. The absence of error messages in the memory on the M50TUB20 engine with MS40.1 is a sign of the complete serviceability of the VANOS system.

Front functional check the MS40.1 should also read the data from the fault memory.

If there are no such messages, then the VANOS system controlled by this controller can be checked with the tester. If the camshaft is switched to an early position while the engine is idling, then power unit with a working VANOS system, it will work extremely unevenly or completely stall (similar to the function check on an engine with DME M3.3.1).

BMW M50 engine problems

The M50 engine is considered one of the most. Listed below possible malfunctions engine, but it is worth considering correct service motor, because with proper operation, the power unit will show itself in a completely different way:

• overheating: advice - check the condition of the radiator, pump, thermostat, the presence of air locks in the cooling system and the radiator cap;
• troit: recheck ignition coils, spark plugs and injectors;
• floating revolutions: possible reasons the occurrence of a malfunction - failure of the idle valve or throttle position sensor;
• antifreeze leakage - the expansion tank is cracked;
• failure of individual ignition coils;
• burnout of power keys of ignition control;
• oil flow along the junction of the oil filter cup, valve cover gasket, sump and front cover;
• the fuel supply is turned off;

The powertrain of the BMW M50 has been replaced with a.

At one time, the M50 engine was a real favorite of BMW. It replaced the M20 engine in 1991. New engine was developed in two variations - 2.0 and 2.5 liters. However, his "life" on the market was short-lived: the release of "fifty" was discontinued in 1996, when new modification with an aluminum block - it was assigned the M52 index.

M50 device

The M50 engine was installed on the e34 and e36 models. In 1992, BMW engineers presented the M50 new system gas distribution called VANOS. The main feature of the innovation was intake camshaft, which made it possible to increase engine thrust at low and medium speeds without losses at high.

The design is a standard 6-cylinder engine, which turned out to be a cast iron block with an aluminum head. Compared to its predecessor, the M20, however, the BMW M50 was a pretty impressive step forward: 24 valve system gas distribution with two camshafts, driven by a chain, and valve drive through hydraulic lifters. The ignition system has also undergone changes - it has become entirely electronic, the distributor was removed as unnecessary and an ignition coil was added to each spark plug.

The M50 became the most successful and reliable engines from BMW, so they got further life - on the basis of the M50, modifications such as the 3-liter M3e36 with a capacity of 240 hp were assembled. and Alpina B3 with 250 hp. The latter option was intended for the American market. The engine weight was about 136 kg.

Modifications М50

Engine modification	Cylinder diameter, mm	Piston stroke, mm	Volume, cm3	Compression ratio	Power, h.p.	Torque, Nm	Max. rpm
M50V20	80	66	1991	10,5:1	150 at 6000 rpm	190 at 4700 rpm, min	6500
М50В20TU VANOS	80	66	1991	11:1	150 at 5900 rpm	190 at 4200 rpm	6500
M50B25	84	75	2494	10:1	192 at 6000 rpm	245 at 4700 rpm	6500
M50B25TU VANOS	84	75	2494	10,5:1	192 at 5900 rpm	245 at 4200 rpm	6500

disadvantages

Despite all the “luck” of the M50, it turned out to be not ideal, like all “long” engines: with strong overheating, the gas joint loses its tightness, as a result of which cracks form on the cylinder head. Excessive oil consumption, which in normal operation is 1 liter per 1000 km, is observed after 300-400 thousand km of run. The consequences are sad - the exhaust valves burn out, and in some cases, due to local overheating, cracks form between them.

Many aftermarket manufacturers install plastic parts into the water pump, which destroys the bearings and pump impeller. Often, with low qualifications of the craftsmen, the result of repairs is incorrectly installed camshafts. Motors of the first years of production suffer from ignition coil failures and cases of burnout of the power keys that control the ignition. But the erosion of the liners is less common than that of the 40 series motors. Many engines of the 50 series have oil leaks - under the gaskets of the pan, valve and front covers, at the connection of the cylinder block with oil filter and the stylus ring.

Some M50s suffer from cylinder shutdown, which in turn cuts off the fuel supply. To turn them on, it is often required not only to eliminate the malfunction, but also to clear the memory. But, at least, these systems do not suffer too much from breakdowns associated with the lambda probe - the oxygen sensor.

Dignity

The M50 has a number of differences from the first generation engines, which, of course, was a big step forward for BMW. It was this engine with its 4 valves per cylinder that founded the fashion for "explosive" engines of the German auto giant, which has survived to this day.

The M50 was the last unit to use a cast iron block and aluminum cylinder head combination, which was a truly loyal and reliable design.

Also, the M50 set the popular standard “1 Nm per 10 cm 3 cylinders”, which was unattainable in the older series engines. The engine is perfectly adapted to 95 gasoline, which, however, cannot be said about the 2-liter versions - even such an octane number is not enough for them. But this problem is solved to some extent with the help of knock sensors. As a result, despite its inherent shortcomings, the BMW M50 became the best in the history of the concern, both in terms of technical and consumer data.

BMW M50 engine operation (video)

In 1990, the popular inline-six BMW M20B25 was replaced by a new, much more advanced and powerful, called BMW M50B25 (popularly nicknamed "Stove"), from the new M50 family (the series also included M50B20, M50B24, S50B30, S50B32 ). The main difference between the M20 and M50 engines lies in the cylinder head; in the new engine, the head was replaced with a more advanced two-shaft, 24-valve with hydraulic compensators (valve adjustment is not threatened). The diameter of the intake valves is 33 mm, the diameter of the exhaust valves is 30.5 mm. Camshafts with a phase of 240/228 are used, a lift of 9.7 / 8.8 mm. And also an improved lightweight intake manifold is used.
Engine management system Bosch Motronic 3.1.
The timing drive in the new M50 engines has also changed, now instead of a belt, a chain is used, the service life of which is 250 thousand km (as a rule, it runs more). In addition, individual ignition coils, an electronic ignition system, other pistons, lightweight connecting rods with a length of 135 mm are used. The size of the M50B25 nozzles is 190 cc.
Since 1992, the M50 engines have received the well-known Vanos intake camshaft timing system, and such engines have become known as the M50B25TU (Technical Update). In addition, these engines use new 140 mm connecting rods and pistons with a compression height of 32.55 mm (38.2 mm on the M50B25).
The control system is replaced by Bosch Motronic 3.3.1.
These power units were used on BMW cars with index 25i.
Since 1995, the M50V25 engine began to be replaced by a new improved M52V25 engine, and in 1996 the production of the M50 series was completed.

Feature of the BMW M50 TU engine

The technical redesign of the M50 engine has led to the following improvements: improved behavior of torque changes, especially in the mid-range speed range, reduced fuel consumption, improved idling performance with a simultaneous decrease in idle speed, improved exhaust performance (reduced emissions), improved responsiveness, better engine acoustics, engine improvements M50TU (M50TU) relative to the M50 engine were achieved by the following design changes and measures: the use of digital motor electronics DME3.3.1 with anti-knock control in a 2.5-liter engine (M50TUB25); the use of a Siemens MS 40.1 engine controller in all E36 and E34 models with an M50TUB20 engine an increase in the compression ratio using the VANOS system, changes in the crank mechanism (new pistons and connecting rods), a new idle speed regulator in a 2.5-liter M50TUB25 (ZWD-5) engine, using a thermofilm air flow meter m of valve stem diameter and the use of one valve spring using disc pushers and spring plates, optimized for masses by changing the valve acceleration characteristics by changing the crankshaft vibration damper

Characteristics of the M50V25 engine

Production	Munich plant
Engine brand	M50
Years of release	1990-1996
Cylinder block material	cast iron
Supply system	injector
Type of	inline
Number of cylinders	6
Valves per cylinder	4
Piston stroke, mm	75
Cylinder diameter, mm	84
Compression ratio	10.0 10.5 (TU)
Engine displacement, cubic cm	2494
Engine power, hp / rpm	192/5900 192/5900 (TU)
Torque, Nm / rpm	245/4700 245/4200 (TU)
Fuel	95
Environmental standards	Euro 1
Engine weight, kg	~198
Fuel consumption in l / 100 km (for E36 325i) - town - track - mixed.	11.5 6.8 8.7
Oil consumption, gr. / 1000 km	up to 1000
Engine oil	5W-30 5W-40 10W-40 15W-40
How much oil is in the engine, l	5.75
Oil change is being carried out, km	7000-10000
Engine operating temperature, deg.	~90
Engine resource, thousand km - according to the plant - on practice	- 400+
Tuning, h.p. - potential - without loss of resource	1000+ 200-220
The engine was installed	BMW 325i E36 BMW 525i E34

VANOS system

Both the power and exhaust characteristics and the driving behavior of the 4-stroke gasoline engine while driving can be significantly improved by the variable intake camshaft angle. VANOS in the M50 engine The opening angle of the intake camshaft of the M50TU engine can be changed, i.e. taking into account the specific operating conditions, switch from late opening to earlier or vice versa. The advantages of the VANOS system are: high power and improved torque in certain speed ranges; reduced NOX and CH emissions in the partial load range; low residual gas at idle speed; due to this, on the one hand, an improved idle speed due to a more favorable mixture, and on the other hand, lower fuel consumption due to a decrease in the idle speed. Improved idle acoustics Better engine response High functional safety Extensive self-diagnosis and trouble-free troubleshooting The VANOS shift system is controlled by the control unit of the corresponding digital motor electronics. In a 2-liter engine, a Siemens MS401 control unit, in a 2.5-liter engine, a Bosch M3.3.1 Motronic control unit.

VANOS design

For both the M50TU20 and M50TU25 engines, many tests were carried out with various options for camshafts and opening angles to identify in each case the most advantageous variable opening angles of the intake camshaft. As a result, the following opening angles were chosen: M50TU20 105º (late changeover) 80º (early changeover) M50TU25 110º (late changeover) 85º (early changeover) This implies for both engine variants the maximum changeover angle of the variable intake camshaft opening angle of 25º KW (crankshaft angle). Components: front helical intake camshaft; chain sprocket with an internal helical rim; a hydraulic-mechanical device for changing the camshaft with one hydraulic piston and a helical gear; solenoid 4/2-way changeover valve; connecting oil pressure line from the cylinder block to the 4/2-way valve; control and diagnostic electronics of the controller;

Modifications

1. M50B25 (1990 - 1992 onwards) - base engine. Compression ratio 10, power 192 HP at 5900 rpm, torque 245 Nm at 4700 rpm.
2. M50B25TU (1992 - 1996 onwards) - added a variable valve timing system at the Vanos intake, changed the connecting rod-piston group, installed other camshafts (phase 228/228, lift 9/9 mm). Compression ratio 10.5, power 192 HP at 5900 rpm, torque 245 Nm at 4200 rpm.

Problems and disadvantages

1. Overheating. The M50 engine is prone to overheating and tolerates it quite hard, so if the engine starts to warm up, check the condition of the radiator, as well as the pump and thermostat, the presence of air plugs in the cooling system and the radiator cap.
2. Troitus. Check the ignition coils, most often the problem is in them, as well as the spark plugs and injectors.
3. Float turns. Often the malfunction is caused by a failed idle valve (KXX). Cleaning will help bring the motor back to its senses. If the problem persists, then look at the throttle position sensor (TPS), temperature sensor, lambda probe, clean the throttle valve.
4. M50 Vanos. The problem is expressed in rattling, loss of power, swimming revs. Repair: purchase of a vanos M50 repair kit.
In addition, due to its age and operating characteristics, BMW engines M50s suffer from high oil consumption (up to 1 liter per 1000 km), which does not drop too much after overhaul. Valve cover and pan gaskets may leak, leaks through the oil dipstick are not excluded. Expansion tank also loves to crack, after which we get antifreeze leakage. At the same time, the sensors of the M50 camshaft, crankshaft (DPKV), coolant temperature, etc., cause problems from time to time.
Despite everything, the BMW M50B25 engine is one of the most reliable power units of the Bavarian manufacturer, and the bulk of the problems are caused by the age and style of operation of the engine. And even such engines roll over 300-400 thousand km, and if the motor was used in a sparing mode and was adequately maintained, then its resource can go far beyond 400 thousand km, because it is not in vain that they have received a reputation of millionaires.
Purchase of the M50B25 engine a good choice for swap and subsequent refinement using a turbocharger. Let's talk about such decisions further.

Diagnostics M50TUB25 with DME M3.3.1

If there are no error messages in the memory, then the control signal is sent to the VANOS system when the M50TUB25 engine with DME M3.3.1 is operating at idle speed. For this, two adapters are used - special BMW tools No. 61 2 050 and 61 1 467. If, at the same time, close the solenoid valve to ground, an engine with a working VANOS system will work extremely unevenly or completely stall.

Diagnostics M50TUB20 with MS40.1

The VANOS system is fully tested with self-diagnostics. The absence of error messages in the memory on the M50TUB20 engine with MS40.1 is a sign of the complete serviceability of the VANOS system. Before checking the function of the MS40.1, the data from the fault memory must also be read. If there are no such messages, then the VANOS system controlled by this controller can be checked with the tester. If the camshaft is switched to an early position while the engine is idling, then the power unit with a working VANOS system will operate extremely unevenly or completely stall (similar to the function test on an engine with DME M3.3.1).

BMW M50B25 engine tuning

Stroker. Camshafts

The most simple and quick option increase power using factory components, this is the installation of a long-stroke crankshaft (stroker). In M50B25 (Without vanos), a knee rises from the M54B30 with a travel of 89.6 mm. It is necessary to buy connecting rods from the same motor, connecting rod bearings, repair pistons, injectors, and main bearings from M50.
We collect (you can leave the firmware, but it's better to tune in) and drive a 3-liter M50B30, with a capacity of about 230 hp and a compression ratio of 10.
The same power can be obtained by purchasing Schrick 264/256 camshafts and adjusting the Motronic stock. As a result, we get 220-230 hp. Let's buy a cold air intake, sports exhaust and get 230+ hp.
The same camshafts on the M50B25 3.0 stroker will give about 250-260 hp.
To get maximum power from the M50B30, you need to buy Schrick 284/284 camshafts, six-throttle intake, BMW S50 injectors, a light flywheel, make cylinder head porting, buy an equal-length exhaust manifold and direct-flow exhaust. Once tuned, this M50B30 develops around 270-280 hp.
If this is not enough, you can bore a block for 86.4 mm pistons from S50B32 and get a displacement of 3.2. Buy S52B32 camshafts and get about 260 hp.
The vanos M50B25 can be converted into a 2.8 liter engine by installing a crankshaft with an 84 mm stroke and connecting rods from M52B28. Together with the SIEMENS MS41 firmware, this will give +/- 220 hp, compression ratio ~ 11.

VANOS system control

The solenoid valve of the VANOS system is controlled by a controller and depends on the coolant temperature, load and engine speed. At the moment of switching the system for changing the angle of opening of the valves, the settings for the start of injection and ignition are changed. To avoid frequent, repeated switching of the VANOS system, the control is carried out in the hysteresis mode.

M50B25 Turbo

In the case when atmospheric engine it is not enough or the costs for its implementation are too high, you can organize a turbo version on a 2.5-liter engine. If tuning is supposed to be budgetary, then a Chinese turbo kit based on the Garrett GT35 (or another, with brains included) is your choice. Alternatively, you can find a used TD05 turbine (or another), weld the manifold, assemble all the piping, clamps, boost controller, intercooler, etc. Put everything on the stock piston, having previously installed a thick cylinder head gasket Cometic, 440 cc injectors, fuel pump Bosch 044, exhaust on 3 ″ pipe, brain EFIS 3.1 (or Megasquirt), adjust it and get about 300 hp at 0.6 bar. At 1 bar ~ 400 HP
Something like this can be built by buying a compressor kit M50 and installing it on a piston stock. The compressor output will be noticeably lower than that of the turbine.
Even more power can be obtained by purchasing and installing a turbo kit on the original Garrett GT35, CP Pistons 8.5 compression, Eagle connecting rods, ARP bolts, performance injectors (~ 550 cc). With kits like this, you can increase the power up to 500 ++ HP. Similar projects can be built on a 3-liter stroker.

Functioning of the VANOS system

The VANOS system in the M50 is controlled by the engine-specific digital electronics. The controller switches the 4/2-way valve by means of an electromagnet and thus acts by means of engine oil pressure on the hydraulic piston. The hydraulic piston is held in one of two possible positions by mechanical stops and the oil pressure acting on it (black and white switching mode). There is a movable gear inside the hydraulic piston. This gear, by means of helical gearing, converts the translational movement of the piston into a rotation of the camshaft - relative to the drive sprocket. The hydraulic piston with gear is mounted coaxially with the intake camshaft in a die-cast aluminum housing located on the front of the cylinder head. The 4/2-way changeover valve is designed in such a way that when there is pressure in one chamber, there is no pressure in the other (backflow). When current is applied to the valve magnet, the piston moves through the armature against the force of the spring to the previous position. The helical spring provides reverse movement to the late position. Thus, in the event of a malfunction of the electromagnet or a failure of the control signal, the camshaft automatically returns to a late position. With this emergency function, the engine can be started even if the VANOS system is faulty. If the camshaft is in an early position during start-up, the engine will not start.

The BMW 5 Series E34 is the third generation of the Bavarian premium business sedan. The premiere of the new model took place in 1987, and sales started in 1988. In 1991, the all-wheel drive version of the BMW 525ix entered the market.

E34 has been updated twice. First time in 1992 - a modified version can be identified by other mirrors. The new ones have become much more harmonious and acquired more aerodynamic forms. The M50 engine received a VANOS variable valve timing system, and a 5-speed one took the place of a 4-speed automatic. The driver's airbag no longer required a surcharge and was included in the list basic equipment like ABS.

Two years later, the BMW 5 Series E34 underwent another restyling. This time, the front grille has been redesigned to be wider. From now on, the German sedan was mandatorily equipped with two airbags - the driver and the front passenger. In 1996, the E34 gave way to the next to the BMW generation 5 series E39. In total, 1,330,000 copies of the third generation "five" were sold. This is almost twice as much as that of its predecessor - E28.

Engines

Gasoline:

R4 1.8 8V (113-115 HP), 518i;

R6 2.0 12V (129 HP), 520i;

R6-VANOS 2.0 24V (150 HP), 520i;

R6 2.5 12V (170 HP), 525i;

R6-VANOS 2.5 24V (192 HP), 525i, 525ix;

R6 3.0 12V (184 hp), 530i;

V8 3.0 32V (217 hp), 530i;

R6 3.4 12V (211 HP), 535i;

V8 4.0 32V (285 hp), 540i;

R6 3.5 24V (315 HP), M5;

R6 3.8 24V (340 HP) M5.

Diesel:

R6 2.4 12V (115 HP) 524td;

R6 2.5 12V (115 HP) 525td;

R6 2.5 12V (143 HP) 525tds.

Looking at such a wide range of engines, a dilemma arises - which motor to choose, more powerful or more economical. But before making a decision, there are a few things that need to be clarified.

If you are looking for a relatively economical gasoline engine, then you should pay attention to the 2-liter engine with variable valve timing VANOS. However, it should be borne in mind that sometimes this system fails. The dynamics with such a motor is not impressive - 10.6 seconds to 100 km / h. But low fuel consumption and rare breakdowns are guaranteed.

An 8-valve 1.8 liter is better not even to consider - it is too weak. Much preferable is the 120-horsepower BMW 520i with М20В20, which the Bavarian inherited from the previous generation E28 model. Its disadvantages: wear on the camshaft, rocker arms, valve seats, and sometimes the valves themselves.

The best compromise between fuel consumption and dynamics is provided by the in-line 6-cylinder 2.5-liter petrol engine, especially its 24-valve version (M50). Fuel consumption in the city is about 15 l / 100 km, and outside it - up to 10 l / 100 km.

Attention! All 12-valve versions of gasoline engines overheat easily, which leads to breakdown of the gasket under the head, and sometimes to damage to the head itself. To rule out the possibility of an accident, it is necessary to constantly monitor the state of the thermostat, and much more often than in any other car, look into the coolant tank. But above all, you need to pay close attention to the engine temperature gauge.

A typical disease of 6-cylinder gasoline engines is the failure of the water pump. Depending on the series, a plastic impeller was installed in them, which, as a result of exposure high temperatures became brittle and separated from the shaft. This led to overheating of the engine and deformation of the block head. It is comforting to note that metal impeller pumps are now available.

The viscous coupling of the fan also requires attention. Its malfunction can lead to overheating of the engine and, as a result, to damage to the block head.

Powerful V8 engines installed since 1992, as well as the top model M5 guarantee not only sporty dynamics, but also huge expenses for fuel, maintenance and repair. Most typical malfunctions: loss of compression, burnout of the collector gaskets and uneven operation.

Rest gasoline engines, although they absorb an impressive amount of fuel, as a rule, they do not create much hassle during operation. However, it must be borne in mind that the BMW 5 E34 is no longer young, and therefore malfunctions associated with big runs quite natural.

Diesel modifications are best avoided. Almost all of them force to solve problems caused by overheating of the block head and its subsequent cracking. In addition, the injection system is capricious and the turbocharger is not too hardy. Today it is more and more difficult to find a service that can handle the repair of a Bavarian injection pump. In addition, diesel versions already have astronomical mileage. Trying to find an unbroken copy borders on a miracle!

M20 series engines (520i and 525i) and 518i and 524td versions are equipped with timing belt, which must be changed every 60,000 km. The rest of the units are equipped with an almost eternal timing chain.

Design features

E34 traditionally for BMW has a drive on rear axle... V lineup there was also an all-wheel drive BMW modification 525ix. The engines were combined with one of four gearboxes: 5 and 6-speed mechanics or 4 and 5-speed automatic. The chassis is based on a MacPherson strut at the front and a multi-link at the rear.

Typical malfunctions

First of all, you need to pay attention to the suspension components. Worn stabilizer struts and bushings, levers, silent blocks, ball joints and shock absorbers should not surprise anyone, because the car is already at a respectable age. If you do not save on substitutes, then after the repair you will not think about the suspension for a long time, because it has a rather strong structure. However, bad roads can quickly finish off the ball, bushings of the front levers and rear beam.

For age reasons, steering problems are not uncommon. After 150-200 thousand km, there is a backlash in the steering gear, and then leaks. Regular maintenance requires a parking brake.

One of the common ailments of the BMW 5 Series E34 is corrosion. It appears on the lower edge of doors, fenders, sills, trunk lid and hatch fuel tank... Rust is often found on brake lines as well.

Electronics also does not stand the test of time: comfort module, central locking, power windows and heating.

An automatic transmission, if the oil and filter are changed in time, will work for a long time. But remember that the lack of only a glass of oil (0.2 l) leads to incorrect operation of the automatic transmission and to rapid wear its components. Nevertheless, often after 150-200 thousand km, malfunctions occur due to damage to the torque converter or planetary gear.

In the transmission, it is worth paying attention to the propeller shaft support and its joints, the rear differential and the axle joints. Problems with the above components are often found in cars from under the owner, who prefers to press the gas pedal harder and all the way to the stop.

Conclusion

Despite these shortcomings, the BMW 5 E34 is considered one of the most durable German cars late 80s and early 90s. Some would argue that the Bavarian sedan can be as reliable as the Mercedes-Benz W124. Unfortunately, at one time, many cars fell into the hands of careless young drivers who did not regret too much BMW and did not take good care of it. Today find E34 in good condition almost impossible. But if you succeed, you will be rewarded with excellent handling and dynamics, very rich equipment, decent comfort and timeless design. True, in addition to the above-mentioned malfunctions, the inconvenience can be delivered by the prices of some of the spare parts, which are by no means cheap.

Diesel engines M-50 F-3 (12ChSPN 18/20)

Diesel M-50 F-3 (M-400) - four-stroke, V-shaped, twelve-cylinder, mechanically pressurized, high-speed marine engine with jet fuel atomization. Available in right-hand and left-hand rotation models. Diesel engine of right rotation differs from diesel engine of left rotation in outward appearance reversing clutch, supercharger, seawater pump, exhaust system, “As well as the location of the fresh water pump and oil injection pump with a centrifuge. The arrangement of units on diesel engines of left and right rotation is mirror-like.

Diesel M-50 F-3 is designed to operate on high-speed hydrofoils. The rocket-type motor ship has one engine, the meteor-type - two and the "satellite" -type - four engines. The diesel engine is equipped with reversible clutches, consisting of friction and gear clutches and ensuring the transfer of rotation from the diesel crankshaft to the propeller shaft (forward motion), the separation of these shafts ( idling) and changing the direction of rotation of the propeller shaft (reverse).

The forward operating power may vary depending on the purpose within the range of 368-736 kW with a corresponding change in the number of shaft revolutions within 1200-1640 rpm, maximum power reverse- 184 kW at 750 rpm and operating time no more than 1 hour.

The crankcase of the diesel engine is cast from an aluminum alloy and consists of two parts. In the upper bearing part there are seven main bearing seats with liners in which the crankshaft rotates. The split steel liners are cast in lead bronze and bored along the shaft journals. The working surface of the liners is coated with a lead-tin alloy. The platforms of the upper part of the crankcase, located at an angle of 60 °, serve for the installation of two six-cylinder blocks.

The crankshaft is made of alloy steel, subjected to nitriding. It has six knees located

in pairs in three planes at an angle of 120 ° to each other. The connecting rod and main journals are connected by round cheeks. A spring shock absorber is attached to the rear flange of the crankshaft, which reduces the unevenness of the torque under variable loads. Six main and six trailed connecting rods are mounted on the diesel crankshaft.

I-section connecting rods are made of alloy steel.

The upper heads of the main and trailed connecting rods are the same and have tin bronze bushings pressed into them. The lower head of the main connecting rod is split: the cover is attached to the main connecting rod using a wedge with two tapered pins. In the lower head of the main connecting rod, a steel liner filled with lead bronze, consisting of two halves, is installed. The trailed connecting rod is connected to the main connecting rod by means of a pin pressed into the eye of the main connecting rod.

The piston is a stamped aluminum alloy. The piston crown is shaped like a Gesselmann combustion chamber. The piston has grooves into which four piston rings, of which two (upper) are compression, and the rest are oil scraper. Gas distribution valves are located in four recesses of the piston crown. The piston pin is made of alloy steel, hollow, with a hardened outer surface, pressed into the piston bosses.

The cylinder blocks are six-cylinder, they are installed on the upper crankcase of the diesel engine and are attached to it with anchor pins. Each cylinder block consists of a jacket, six cylinder liners and a head. In the upper part, the sleeve has a shoulder, with which it rests on the surface of the groove in the block jacket. The lower belt of the cylinder sleeve is sealed by five rubber rings: four serve to seal the water cavity, and the fifth (lower) prevents oil from leaking out of the upper crankcase cavity.

Rice. 1. Diesel M-50F-3

Diesel engines of the M-400 type have two six-cylinder monoblocks (the head is cast in one piece with the cylinder block). In monoblocks, six cylinder liners are pressed in, each of which is a connection of two pipes: an inner one made of alloy steel and an outer one made of carbon steel. The working surface of the inner tube is nitrided.

The gas distribution mechanism is driven from the crankshaft by means of an inclined gear located at the front of the diesel engine. Each cylinder has four valves - two inlet and two outlet. The valve is pressed against the seat by three coil springs. Each head of the block has two camshafts, the cams of which directly act on the valve discs, which are interconnected by cylindrical gears.

The order of operation of the cylinders on a diesel engine of right rotation: 1l-6pr-5l-2pr-3l-4pr-6l-1pr-2l-5pr-4l-3pr; on a diesel engine of left rotation: 1pr-6l-4pr-3l-2pr-5l-6pr-1l-3pr-4l-5pr-2l.

Fuel system. From the supply tank through the filter, the fuel enters the fuel priming pump, from which it is supplied under a pressure of 2-4 bar through two parallel-connected fuel filter into the high pressure fuel pump and injectors.

The fuel pump is a twelve-plunger pump with two-way cut-off and with separate suction and cut-off. Plunger diameter - 13 mm, plunger stroke - 12 mm. Fuel supply pressure 700-1000 bar. The order of operation of the pump plungers, counting from the drive end of the roller, is as follows: 2-11-10-3-6-7-12-1-4-9-8-5.

Diesel regulator - all-mode, indirect action, with an elastically connected cataract. Provides speed stability in the range from 500 to 1850 rpm.

The nozzle is of a closed type, with a hydraulically controlled needle. The injector nozzle has eight spray holes with a diameter of 0.35 mm, located so that when fuel is sprayed, a cone with an apex angle of 140 ° is formed. The fuel injection pressure of 200 bar ensures that the smallest particles are atomized evenly throughout the compressed air volume in the combustion chamber.