Bmw n62 engine block

The BMW M50 motor is available in two versions, with a volume of 2.0 and 2.5 liters and was produced at the Steier plant. Until 1996, a total of 943,795 engines were produced.
The BMW M50 from the M20 has many design features, including lower C O2 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 upper camshafts (DOH C), which are driven by two timing chains (toothed belt in the M20). Pushers have low operating costs. A 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. The intake manifold has completely smooth inner walls and is 50% lighter than aluminum vy intake manifold from M20.

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

To achieve the goals set by the power indicators, a completely new DOC H cylinder head (with two overhead camshafts) with a 4-valve technique was developed for the M50 engine. The feature of which is the low gas exchange work. The ideal position of the spark plug and the reduction in the movable mass of each valve .

BMW M50B20 engine

This version of the power unit was installed on,

BMW M50B24 engine

The 2. 4-liter version of the BMW M50 engine with a volume of 2.4 liters (2394 cc) which was produced for cars of 3 and 5 series of Thai specification. Its maximum power is 188 hp. (138 k W) 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 specifications

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

   Engine structure

BMW M50 engine structure / mechanics

Engine M50: 1 — Oil Pump; 2 — drive belt; 3 — coolant pump; 4 — Thermostat; 5 — oil filter; 6 — Chains; 7 — Intake
collector; 8 — Candles and ignition coils; 9 — Camshafts; 10 — hydraulic pusher;

Crankcase / crank mechanism

Feature:

  • new development — torsionally stiff housing 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;

Technical parameters of the cylinder block, mm:

Block crankcase engine M50: 1 — cylinder block with pistons; 2 — Hexagon bolt M10X75; 3 — an oil nozzle; 4 — Plug D \u003d 12. 0M M; 5 — a bolt of a cover of the bearing; 6 — oil nozzle; 7 — Cover D \u003d 45M M; 8 — threaded plug; 9 — a sealing ring; 10 — Centering sleeve D \u003d 13. 5M M; 11 — Centering sleeve D \u003d 10, 5M M; 12 — Centering sleeve D \u003d 14. 5M M; 13 — Opl. Crankcase kit asbestos-free;

Crankshaft with bearing shells for engine bearings M50: 1 — Revolving crankshaft with bearing shells; 2 and 3 — Inserts of the persistent bearing; 4, 5, 6 and 7 — the bearing shell;

Pistons

The M50 motor is equipped with aluminum pistons with temperature-controlled inserts. At the bottom of the piston there are four valve pockets, two on the inlet and outlet valves.

The piston bottom of the 2. 5-liter engine additionally has a segmented recess (no segmented recess in the 2-liter engine). The piston bottoms are cooled by oil spray. Sprinklers are located in the crankcase in the area of \u200b\u200bthe crankshaft main bearings.

M50 Motor Piston: 1 — Piston; 2 — Piston finger; 3 — snap ring; 4 — Repair kit for piston rings;

M50 engine piston: on the left side the piston of a 2. 0-liter engine, on the right — a 2. 5-liter power unit;

Piston rings:

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

Camshaft drive

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

  • Main drive (primary circuit):

    • from crankshaft to exhaust camshaft with guide bar on driven chain branch
    • hydraulically shock absorbing tension bar
  • Auxiliary drive (secondary circuit):

    • from exhaust to intake camshaft
    • guide rail and hydraulically shock absorbing tensioner

Both chains are cooled in the places where they leave the sprockets by spraying oil. The primary drive chain is provided with a sprinkler located above the first main bearing of the crankshaft. The secondary drive chain is equipped with a sprinkler in the upper chain tensioner housing.

The valves are driven by two semi-support upper cast hollow camshafts.

Camshafts and camshafts are mounted complete with a bearing housing to facilitate maintenance.

The cylinder head of the engine M50: 1 — The cylinder head with support strips; 2 — Support plate discharge side; 3 — Centering sleeve D \u003d 9. 5M M; 4 — Hexagon nut with washer; 5 — The directing plug of the valve; 6 — Intake valve seat ring; 7 — a ring of a saddle of the final valve; 8 — Centering sleeve D \u003d 9. 5M M; 9 — An adjusting pin of M7X95; 10 — Installation pin M7 / 6X29. 5; 11 — An adjusting pin of M7X42; 12 — An adjusting pin of M7X55; 13 — An adjusting pin of M6X30-Z N; 14 — An adjusting pin of M6X45; 15 — An adjusting pin of M6X35-Z N; 16 — Centering sleeve D \u003d 8. 5X9M M; 17 — An adjusting pin of M8X50; 18 — Centering sleeve D \u003d 10, 5M M; 19 — Cover D \u003d 28M M; 20 — Threaded plug M24X1. 5; 21 — Threaded plug M18X1. 5; 22 — Threaded plug M8X1; 23 — Threaded plug M12X1. 5; 24 — a sealing ring; 25 — Cover 22. 0M M;

Characteristic of valve seats

Parameter

Valve seat

intake graduation intake graduation
M50V20 M50V25
Diameter of the seat bore in the head of the block, mm:
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 from 0.00 to +0.025 from 0.00 to +0.025
Bevel angle, degrees 45 45 45 45
External Correction Corner 15 15 15 15
Corner internal correction 60 60 60 60
Width of a working facet, mm 1,40-1,90 1,40-1,90
Outer diameter mm
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 from 0.00 to -0.025 from 0.00 to -0.025
Seat height mm
7,3 7,3
  • 1st repair
7,5 7,5
  • 2nd repair
7,7 7,7
with tolerance, mm from 0.00 to -0.01 from 0.00 to -0.01

M50 engine valves

Parameters Intake 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
Diameter of the rod, mm
6,975 6,975
  • 1st repair
7,10 7,10
  • 2nd repair
7,20 7,20
  • manufacturing tolerance
from 0.00 to -0.015 0.0 to -0.015
Clearance between guide bushings and valve stems 0,5 0,5
Guide Sleeve Parametersmm
total length 43,5
Outside diameter:
12,5
  • 1st rem. The size
12,6
  • 2nd rem. The size
12,7
Manufacturing tolerance from +0.033 to +0.044
Inner diameter:
7,0
  • 1st rem. The size
7,1
  • 2nd rem. The size
7,2
Manufacturing tolerance from 0.0 to +0.015
Diameter of holes for guide bushings:
12,5
  • 1st rem. The size
12,6
  • 2nd rem. The size
12,7
Manufacturing tolerance from 0.00 to -0.018

Cylinder head

Cylinder head of the M50 engine with a diametrically opposite inlet and outlet channels with

  • four valves per cylinder
  • two camshafts
  • hydraulically controlled clearance pushers (HVA)

Very small valve angles make the combustion chamber flat and allow the concentration of the combustible mixture around the centrally located spark plug.

Sectional cylinder head BMW M50

Hydraulic clearance and valve control

(HVA) is integrated in a disk pusher. This reduces noise generation and facilitates maintenance:

  • No need to install and check valve clearance
  • Timing phases are clearly observed for a long time.

The hydraulic disk pusher mainly consists of two moving parts — the disk pusher and the cylinder.

By the force of the spring, both parts move apart until there is no gap between the camshaft and valve stem.

The non-return valve is used to fill and lock the high-pressure chamber.

Oil circulation

Oil is supplied through a duocentric pump with an internal rotor and an integrated oil pressure control system (similar to c).

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

The oil filter is mounted on the intake side in a vertical position. The paper filter cartridge can be replaced on top. To replace the filter, the central fixing bolt of the oil filter cover is unscrewed.

Sectional M50 Engine — Front View

Cooling system

A water pump is integrated in the crankcase. The end o-ring has a ceramic surface, the impeller is made of plastic, and the housing is made of aluminum.

The removal of warm water for heating is carried out from the cylinder head.

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

Auxiliary units

Auxiliary units are driven by a V-belt that does not require maintenance.
  The power steering pump and the generator are located on the left, the air conditioning compressor (S A) is on the right, close to the engine and mounted rigidly, not elastic.

Auxiliary units are driven on two levels:

  • 1st level (main drive):

    • crankshaft — water pump (fan) — generator — power steering pump or tandem pump (level control)
  • 2 level (additional drive):

    • crankshaft — air conditioning compressor

An external spring booster belt tensioner located on the driven branch of the belt is hydraulically absorbed in one direction. The tension roller is made of plastic.

Spark plug

A separate plastic redirecting roller near the generator increases its angle of coverage. The M50 engine ignition system (RZV) also uses a spark plug — an “F” spark plug with an SAE contact and a three-pointed side electrode.

The side electrode was developed by BMW in collaboration with suppliers specifically 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 the new candle is 0.9 mm +/- 0.1 mm. Candle has resistance

Ignition coil

Each spark plug has its own ignition coil. The coil is screwed to a packet of iron, thus providing electrical contact with the mass.

The high voltage is supplied to the spark plug using a silicone funnel, a contact rod with a noise suppressor and a conical contact spring. Which presses on the SAE contact of the spark plug. This design provides the highest secondary voltage of the ignition system, as there are no high voltage wires and losses associated with voltage distribution.

M50 engine ignition coil: 1 and 2- Ignition coil; 3 — The tip of the wire to the spark plug; 4 — Hexagon nut; 5 — Shield; 6 — Hexagon bolt; 7 — Connector plug housing; 8 — spark plug;

The ignition coil is galvanically disconnected, i.e. the end of the secondary winding is withdrawn from the coil. It is designated “4A” and is the middle contact of a 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 disconnecting the plug, this contact is disconnected last.

BMW M50T U engine

Starting in September 1992 (P U92), the BMW M50 engine installed on the BMW E36 and E34 is replaced by a revised version. M50 T U   (T U — technically redesigned).

BMW M50 T U Motor Feature

The technical revision of the M50 engine led to the following improvements:

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

Improvements to the M50T U engine (M50T U) 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 M S 40.1 engine controller in all E36 and E34 models with an engine M50TUB20
  • increased compression
  • using the VANOS system
  • changes in the crank mechanism (new pistons and connecting rods)
  • the new idle control in the 2. 5-liter engine M50TUB25 (ZWD-5)
  • using thermofilm air flow meter
  • reducing the diameter of the valve stem and using one valve spring
  • the use of disk pushers and spring plates optimized by mass
  • changing valve acceleration characteristics
  • a change in the vibration damper

BMW M50 T U engine specifications

  technical specifications M50TUB20 M50TUB25
engine’s type inline 6-cylinder
mounting position in front 30º to the exhaust side
side view 2.28º back
effective engine size dm³ 1990 2494
piston stroke mm 66 75
cylinder diameter mm 80 84
piston stroke / bore ratio 0,825 0,893
power k W / hp 110/150 140/190
at speed rpm 5900 5900
torque Nm 190 245
at speed rpm 4200 4200
power density k W / dm³ 55,3 56,1
compression ratio :1 11,0 10,5
cylinder operation 1-5-3-6-2-4
maximum piston speed m / s 14,3 16,25
valve diameter mm
30 33
27 30,5
valve stroke mm
  • inlet / outlet
9, 0/9,0 9, 0/9,0
flow area on / off 228º / 228º 228º / 228º
valve opening angle on / off 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

Both power characteristics and exhaust gas performance. And the behavior of a 4-stroke gasoline engine while driving while driving can be significantly improved with a variable opening angle of the intake camshaft.

The opening angle of the intake camshaft of the M50T U engine can be changed, i.e. taking into account specific operating conditions. Switch from late opening to earlier or vice versa.

Advantages of the VANOS system:

  • high power and improved torque in certain speed ranges
  • reduced content of NOX and C H emissions in the partial load range
  • low residual gas content at idle speed; due to this. On the one hand. Improved idle quality due to a more favorable mixture. And on the other hand. Lower fuel consumption due to a decrease in the idle speed. Improved idling acoustics
  • better engine response
  • high functional safety
  • extensive self-diagnosis and trouble-free troubleshooting

The VANOS switching system is controlled by the control unit of the corresponding digital motor electronics. In a 2-liter engine, a Siemens M S401 control unit, in a 2. 5-liter engine — a Motronic control unit from Bosch M3.3.1.

VANOS construction

Both for the M50T U20 engine and the M50T U25 engine. A lot of tests were carried out with various options for camshafts and opening angles to identify in each case the most favorable variable opening angles of the intake camshaft.

As a result, the following opening angles were selected:

  • M50T U20

    • 105º (late switch)
    • 80º (early shift)
  • M50T U25

    • 110º (late switch)
    • 85º (early shift)

From this it follows for both engine variants the maximum switching angle of the variable intake camshaft opening angle of 25º K W (crankshaft angle).

Components:

  • intake camshaft with helical crown in front;
  • chain sprocket with internal helical crown;
  • hydraulically-mechanical camshaft shifter with one hydraulic piston and helical gear;
  • 4/2-channel solenoid switching valve;
  • connecting oil pressure line from the cylinder block to the 4/2-channel valve;
  • control and diagnostic electronics of the controller;

VANOS system operation

The VANOS system in the M50 runs under the control of a digital electronic engine. Using an electromagnet, the controller switches the 4/2-channel valve 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 means of mechanical stops and the oil pressure acting on it (black-and-white switching mode). Inside the hydraulic piston is a movable gear. This gear through helical gearing converts the translational movement of the piston into a camshaft rotation — relative to the drive sprocket.

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

The 4/2-channel switching valve is designed so that if there is pressure in one of its chambers, there is no pressure in the other (reverse outflow). When current is applied to the valve magnet, the piston moves through the armature against the spring force to its previous position. The coil spring provides reverse movement to a late position. Thus, if the electromagnet fails or the control signal fails, the camshaft automatically returns to its late position.

With this emergency function. The motor can be started even if the VANOS system is faulty. In the early position of the camshaft during start-up, the engine will not start.

VANOS System Management

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

At the moment of switching the system for changing the angle of opening of the valves, changes occur in the settings for the beginning of injection and ignition.

To avoid frequent, repeated switching of the VANOS system, control occurs in hysteresis mode.

Diagnostics M50TUB25 with DME M3.3. 1

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

Diagnostics M50TUB20 with M S40. 1

Using self-diagnosis, the VANOS system is fully verified. The absence of error messages in the memory on the M50TUB20 engine with M S40.1 is a sign of the complete health of the VANOS system.

Before functional check   M S40.1 should also read data from the fault memory.

If there are no such messages, then the VANOS system managed by this controller can be checked using a tester. If the camshaft is switched to an early position while the engine is idling. Then a power unit with a working VANOS system will work extremely unevenly or completely die out (similar to checking operation on an engine with DME M3.3. 1).

BMW M50 engine problems

The M50 engine is considered one of the most. Possible engine malfunctions are listed below, but it is worth considering the correct maintenance of the 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, air plugs in the cooling system and the radiator cap;
  • troit: recheck ignition coils, candles and nozzles;
  • revolutions are floating: the possible causes of the malfunction are the failure of the idle valve or the throttle position sensor;
  • antifreeze leak — the expansion tank is cracked;
  • failure of individual ignition coils;
  • burnout of power ignition control keys;
  • oil leak at the junction of the oil filter cup, valve cover gasket, sump and front cover;
  • fuel supply is turned off;

The powertrain of the BMW M50 has been replaced by.

At one time, the M50 engine was a real favorite of BMW. He replaced the M20 motor in 1991. The new engine was developed in two variations — 2.0 and 2.5 liters. However, his “life” in the market was short-lived: the release of “fifty” was discontinued in 1996, when a new modification with an aluminum block arose — 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 with a new gas distribution system called VANOS. The main “feature” of the innovation was the intake camshaft, which allowed to increase the engine thrust at low and medium speeds without loss at high.

The design is a standard 6-cylinder engine, at the disposal of which was a cast-iron block with an aluminum head. However, compared with its predecessor M20, the BMW M50 was a pretty impressive step forward: a 24-valve timing system with two camshafts, driven by a chain. And a valve drive through hydraulic lifters. The ignition system has also undergone changes — it has become completely electronic, the distributor was removed as unnecessary and an ignition coil was added to each candle.

The M50 became the most successful and reliable engines from BMW, so they got a further life — on the basis of the M50, modifications such as the 3-liter M3e36 with a power 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 M50

Engine modification Cylinder diameter mm Piston stroke mm Volume cm3 Compression ratio Horsepower Torque, Nm Max. Rpm
M50V20 80 66 1991 10, 5:1 150 at 6000 rpm 190 at 4700 rpm 6500
M50V20T U 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
M50B25T U VANOS 84 75 2494 10, 5:1 192 at 5900 rpm 245 at 4200 rpm 6500

disadvantages

Despite all the “luckiness” of the M50, it was still not ideal, like all the “long” engines: with severe 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 already observed after 300-400 thousand kilometers. The consequences are sad — exhaust valves burn out, and in some cases, cracks form between them due to local overheating.

Many parts manufacturers install plastic parts in the water pump, causing damage to the bearings and impeller of the pump. Often with poorly qualified craftsmen, the result of the repair is incorrectly installed camshafts. The engines of the first years of production suffer from failures of the ignition coils and cases of burnout of the power keys that control the ignition. But erosion of the liners is less common than the motors of the 40 series. Many 50 series engines show oil leakage — under the gaskets of the pan, valve and front covers, by connecting the cylinder block to the oil filter and the dipstick ring.

Some M50s suffer cylinder shutdown, which in turn shuts off the fuel supply. To turn them on often requires not only fixing the malfunction, but also cleaning the memory. But, at least, these systems do not suffer too much from breakdowns associated with the lambda probe — the oxygen sensor.

Advantages

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 established the fashion for the “explosive” engines of the German auto giant, which has survived to this day.

The M50 was the last unit to use a combination of “cast-iron block and aluminum cylinder head”, which was a truly faithful and reliable design.

Also, the M50 set the popular standard “1 Nm per 10 cm 3 cylinders”, which was unattainable in the engines of the old series. The engine 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 to some extent solved by knock sensors. As a result, despite its inherent disadvantages, the BMW M50 was the best in the history of the concern both in technical and consumer data.

BMW M50 engine operation (video)

In 1990, the popular BMW M20B25 inline six was replaced by a new, much more advanced and powerful one, called the BMW M50B25 (popularly nicknamed the “Plate”), from the new M50 family (the series also includes 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, exhaust 30.5 mm. Camshafts with a phase of 240/228 are used, a lift of 9.7 / 8.8 mm. And also applied advanced lightweight intake manifold.
  Engine management system Bosch Motronic 3.1.
  The timing drive in the new M50 engines has also changed, now a chain is used instead of a belt, the service life of which is 250 thousand km (usually more). In addition, individual ignition coils, an electronic ignition system, other pistons, lightweight 135 mm connecting rods are used. The nozzle size of the M50B25 is 190 cc.
  Since 1992, the M50 engines have received the well-known variable valve timing system on the Vanos intake shaft. And these motors became known as the M50B25T U (Technical Update). In addition, new 140 mm long connecting rods and pistons with a compression height of 32.55 mm (38.2 mm on the M50B25) were used in these engines.
  The control system is replaced by Bosch Motronic 3.3.1.
  These power units were used on BMW cars with an index of 25i.
  Since 1995, the M50V25 engine began to be replaced by a new and improved M52B25 motor, and in 1996 the production of the M50 series was completed.

BMW M50 T U Motor Feature

The technical revision of the M50 engine led to the following improvements: the nature of changes in torque was improved. Especially in the medium speed range. Fuel consumption was improved. The idle speed was improved while the idle speed was reduced. The exhaust performance was improved (emission toxicity reduction). The throttle response improved engine acoustics Engine improvements M50T U (M50T U) relative to the M50 engine were achieved by the following design changes and measures: We use DME3.3.1 digital motor electronics with anti-knock control in a 2. 5-liter engine (M50TUB25) using the Siemens M S 40.1 engine controller in all E36 and E34 models with the M50TUB20 engine increasing the compression ratio using the VANOS system by changing the crank mechanism (new pistons and connecting rods) with a new idle regulator in a 2. 5-liter M50TUB25 (ZWD-5) engine using a thermofilm air mass meter by reducing the diameter of the valve stem and using one valve spring using poppet pushers and poppet to springs optimized for masses by changing the characteristics of valve acceleration by changing the vibration damper

Characteristics of the engine M50V25

Production   Munich plant
Engine make M50
Years of release 1990-1996
Cylinder block material cast iron
Supply system injector
A type in-line
Number of cylinders 6
Valves per cylinder 4
Piston stroke mm 75
Cylinder diameter mm 84
Compression ratio 10. 0
  10.5 (T U)
Engine displacement, cc 2494
Engine power, hp / rpm 192/5900
  192/5900 (T U)
Torque, Nm / rpm 245/4700
  245/4200 (T U)
Fuel 95
Environmental standards Euro 1
Engine weight kg ~198
Fuel consumption, 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 carried out, km 7000-10000
Engine operating temperature, deg. ~90
Engine resource, thousand km
  — according to the factory
   — on practice

400+
Tuning, hp
  — potential
  — without loss of resource
1000+
200-220
The engine was installed BMW 325i E36
  BMW 525i E34

VANOS system

Both power characteristics and exhaust gas performance. And the behavior of a 4-stroke gasoline engine while driving while driving can be significantly improved with a variable opening angle of the intake camshaft. VANOS in the M50 engine The opening angle of the intake camshaft of the M50T U engine can be changed, i.e. taking into account specific operating conditions. Switch from late opening to earlier or vice versa. Advantages of the VANOS system: high power and improved torque in certain ranges of revolutions; reduced content of the share of NOX and C H of exhaust gases in the part-load range; insignificant residual gas content at idle speed; due to this. On the one hand. Improved idle quality due to a more favorable mixture. And on the other hand. Lower fuel consumption due to a decrease in the idle speed. Improved idling acoustics; better engine response; high functional safety; extensive self-diagnosis and trouble-free error search. The VANOS switching system is controlled by the control unit of the corresponding digital motor electronics. In a 2-liter engine, a Siemens M S401 control unit, in a 2. 5-liter engine — a Motronic control unit from Bosch M3.3.1.

VANOS construction

Both for the M50T U20 engine and the M50T U25 engine. A lot of tests were carried out with various options for the camshafts and opening angles to identify in each case the most favorable variable opening angles of the intake camshaft. As a result, the following opening angles were selected: M50T U20 105º (late shift) 80º (early shift) M50T U25 110º (late shift) 85º (early shift) From this it follows for both engine variants the maximum switching angle of the variable intake camshaft is 25º K W (crankshaft angle). Components: intake camshaft with helical crown in front; chain sprocket with internal helical crown; hydraulically-mechanical camshaft shifter with one hydraulic piston and helical gear; 4/2-channel solenoid switching valve; connecting oil pressure line from the cylinder block to the 4/2-channel valve; control and diagnostic electronics of the controller;

Modifications

1. M50B25 (1990 — 1992 onwards) — the base engine. Compression ratio 10, power 192 hp at 5900 rpm, a torque of 245 Nm at 4700 rpm.
  2. M50B25T U (1992 — 1996 onwards) — a system for changing the gas distribution phases at the Vanos inlet was added, the connecting rod and piston group was changed, other camshafts were installed (phase 228/228, 9/9 mm lift). Compression ratio 10. 5, power 192 hp at 5900 rpm, a torque of 245 Nm at 4200 rpm.

Problems and weaknesses

1. Overheating. The M50 engine is prone to overheating and transfers it quite hard, so if the motor starts to warm up, check the condition of the radiator, as well as the pump and thermostat. The presence of air jams in the cooling system and the radiator cap.
  2. Troit. Check the ignition coils, most often the problem is in them, as well as spark plugs and nozzles.
  3. Float speed. Often a malfunction is caused by a failed idle valve (KXX). Cleaning will help bring the motor to its senses. If the problem persists, then see the throttle position sensor (TPS), temperature sensor, lambda probe, clean the throttle.
  4. M50 Vanos. The problem is expressed in rattling, loss of power, swimming speed. Repair: purchase of Vanos M50 repair kit.
  In addition, due to its age and operating characteristics, BMW M50 engines suffer from high oil consumption (up to 1 liter per 1000 km). Which does not decrease too much after a major overhaul. The valve cover and sump gaskets may leak, and leakages through the dipstick are also possible. The expansion tank also likes to crack, after which we get a leak of antifreeze. However, periodically problems are caused by the sensors of the M50 camshaft, crankshaft (DPK V), coolant temperature, etc.
  Despite everything, the BMW M50B25 engine is one of the most reliable power units of the Bavarian manufacturer. And most of the problems are caused by the age and style of operation of the motor. And even such engines roll over 300-400 thousand km, and if the engine was used sparingly and adequately maintained, its resource can far exceed 400 thousand km. Because it was not for nothing that they gained a reputation of millionaires.
  Buying an M50B25 engine is a good choice for a swap and subsequent refinement using a turbocharger. Further we will talk about such decisions.

Diagnostics M50TUB25 with DME M3.3. 1

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

Diagnostics M50TUB20 with M S40. 1

Using self-diagnosis, the VANOS system is fully verified. The absence of error messages in the memory on the M50TUB20 engine with M S40.1 is a sign of the complete health of the VANOS system. Before checking the operation in M S40. 1, the data from the fault memory should also be read. If there are no such messages, then the VANOS system managed by this controller can be checked using a tester. If the camshaft is switched to an early position while the engine is idling. The power unit with a working VANOS system will work extremely unevenly or completely die out (similar to checking the operation on an engine with DME M3.3. 1).

BMW M50B25 engine tuning

Stroker. Camshafts

The easiest and fastest option to increase power using factory components is to install a long-stroke crankshaft (stroker). In the M50B25 (Without Vanos), a knee from the M54B30 with a stroke of 89.6 mm rises. From the same motor it is necessary to buy connecting rods, connecting rod bearings, repair pistons, nozzles, and main bearings from M50.
  We assemble (we can leave the stock 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 tuning Motronic stock. As a result, we get 220-230 hp We buy a cold air intake, a 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 with the M50B30, you need to buy Schrick 284/284 camshafts, a six-throttle inlet, injectors from the BMW S50, a lightweight flywheel. Porting the cylinder head. Buy an equal-length exhaust manifold and direct exhaust. After tuning, this M50B30 develops about 270-280 hp.
  If this is not enough, you can bore the block under the pistons 86.4 mm from the S50B32 and get a working volume of 3.2. We will buy S52B32 camshafts and we will receive about 260 hp
  Vanos M50B25 can be converted into a 2.8 liter engine by installing a crankshaft with a stroke of 84 mm and connecting rods from M52B28. Together with SIEMENS M S41 firmware this will give +/- 220 hp, compression ratio ~ 11.

VANOS System Management

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

M50B25 Turbo

In the case when the atmospheric engine is small or the costs of its implementation are too high, you can organize a turbo version on a 2. 5-liter engine. If tuning is supposed to be budget, then the Chinese turbo kit based on the Garrett G T35 (or another, with brains included) is your choice. As an option, you can find a used T D05 turbine (or another), weld the collector, collect all the pipings, clamps, boost controller, intercooler and so on. Put everything on the stock piston, pre-installing a thick cylinder head gasket Cometic, 440 cc injectors, Bosch 044 fuel pump, 3 ″ exhaust pipe. EFI S 3.1 brain (or Megasquirt). Set it up 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 drain. The return on the compressor will be noticeably lower than that of the turbine.
  You can get even more power by purchasing and installing a turbo kit on the original Garrett G T35, C P Pistons pistons for compression ratio 8. 5, Eagle connecting rods, ARP bolts. Production nozzles (~ 550 cc). With such kits, you can increase the power to 500 ++ hp. Similar projects can be built on a 3-liter striker.

VANOS system operation

The VANOS system in the M50 runs under the control of a digital electronic engine. Using an electromagnet, the controller switches the 4/2-channel valve 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 means of mechanical stops and the oil pressure acting on it (black-and-white switching mode). Inside the hydraulic piston is a movable gear. This gear through helical gearing converts the translational movement of the piston into a camshaft rotation — relative to the drive sprocket. A hydraulic piston with a gear is installed coaxially with the intake camshaft in a die-cast aluminum housing located on the front side of the cylinder head. The 4/2-channel switching valve is designed so that if there is pressure in one of its chambers, there is no pressure in the other (reverse outflow). When current is applied to the valve magnet, the piston moves through the armature against the spring force to its previous position. The coil spring provides reverse movement to a late position. Thus, if the electromagnet fails or the control signal fails, the camshaft automatically returns to its late position. With this emergency function. The motor can be started even if the VANOS system is faulty. In the early position of the camshaft during start-up, the engine will not start.

The BMW 5 Series E34 is the third generation of the premium Bavarian business class 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 model entered the market.

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

Two years later, the BMW 5 Series E34 underwent another restyling. This time, the front grille was changed, which became wider. From now on, the German sedan became mandatory to be equipped with two airbags — the driver and front passenger. In 1996, the E34 gave way to the next generation of BMW 5 Series E39. In total, 1,330,000 copies of the “five” of the third generation were sold. This is almost twice as much as its predecessor — E28.

Engines

Petrol:

R4 1.8 8V (113-115 h.p.), 518i;

R6 2.0 12V (129 H P), 520i;

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

R6 2.5 12V (170 H P), 525i;

R6-VANOS 2.5 24V (192 h.p.), 525i, 525ix;

R6 3.0 12V (184 h.p.), 530i;

V8 3.0 32V (217 H P), 530i;

R6 3.4 12V (211 H P), 535i;

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

R6 3.5 24V (315 H P), M5;

R6 3.8 24V (340 H P) M5.

Diesel:

R6 2.4 12V (115 H P) 524td;

R6 2.5 12V (115 H P) 525td;

R6 2.5 12V (143 H P) 525tds.

Looking at such a wide range of engines, a dilemma arises — which engine to choose, more powerful or more economical. But before making a decision, it is necessary to clarify a few points.

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

The 8-valve 1.8 liter is better not to even consider — it is too weak. Much preferable is the 120-horsepower BMW 520i with the M20B20, which the Bavarian inherited from the previous generation E28. Its disadvantages: wear of the camshaft, rocker arm, 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 gasoline engine, especially its 24-valve version (M50). Fuel consumption in the city is about 15 l / 100 km, and beyond — up to 10 l / 100 km.

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

A typical disease of 6-cylinder gasoline engines is the failure of a water pump. Depending on the series, a plastic impeller was installed in them, which, as a result of exposure to 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 that pumps with a metal impeller are currently available.

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

Powerful V8 engines, installed since 1992, as well as the top M5 model guarantee not only sports dynamics, but also huge expenses for fuel, maintenance and repair. The most typical malfunctions: a drop in compression, burnout of the manifold gasket and uneven operation.

The remaining gasoline engines, although they absorb an impressive amount of fuel, as a rule, do not create much trouble during operation. However, it should be borne in mind that the BMW 5 E34 is no longer young, and therefore the malfunctions associated with high mileage are quite natural.

Diesel modifications are best avoided. Almost all of them are forced to solve problems caused by overheating of the head of the block and its subsequent cracking. In addition. The injection system is capricious and the turbocharger is not too hardy. Today it is becoming increasingly difficult to find a service that will overpower the repair of the Bavarian fuel pump. In addition, diesel versions already have astronomical mileage. Trying to find an uninhibited instance borders on a miracle!

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

Design Features

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

Typical malfunctions

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

For age reasons, steering problems are not uncommon. After 150-200 thousand km, a backlash appears 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 the doors, wings, sills, boot lid and fuel filler flap. Often rust is also found on brake lines.

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

An automatic transmission, if you change the oil and filter in time, will work for a long time. But remember that the lack of just a glass of oil (0.2 l) leads to improper operation of the automatic transmission and to the rapid deterioration of its components. However, 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 hinges, rear differential and axle joints. Problems with the above components are often found in cars from under the owner who prefers to press the gas pedal more sharply and to the stop.

Conclusion

Despite these shortcomings, the BMW 5 E34 is considered one of the most enduring German cars of the late 80s and early 90s. Some would argue that the reliability of the Bavarian sedan can be compared with the Mercedes-Benz W124. Unfortunately, at one time a lot of cars fell into the hands of nonchalant young drivers who did not spare the BMW too much and cared poorly about it. Today it is almost impossible to find E34 in good condition. But if you succeed, then the reward will go to excellent handling and dynamics, very rich equipment, decent comfort and timeless design. True, in addition to the malfunctions mentioned above, inconvenience can be caused by the prices of some of the spare parts, which are by no means cheap.

Diesels type M-50 F-3 (12CHSPN 18/20)

Diesel M-50 F-3 (M-400) is a four-stroke, V-shaped, twelve-cylinder, with mechanical supercharging, high-speed marine engine with jet spraying of fuel. Models of right and left rotation are available. The right-hand diesel differs from the left-hand diesel in the appearance of the reversible clutch, supercharger, overboard water pump, exhaust system. “as well as in the location of the fresh water pump units and oil pump with a centrifuge. The location of the units on the left and right diesels is a mirror.

The diesel M-50 F-3 is designed to operate on high-speed hydrofoils. On the motor ship of the «rocket» type, one engine is installed, of the «meteor» type — two, and of the «satellite» type — four engines. The diesel engine is equipped with reversible couplings. Consisting of friction and gear couplings and providing transmission of rotation from the crankshaft of the diesel engine to the propeller shaft (forward). Uncoupling of these shafts (idle) and a change in the direction of rotation of the propeller shaft (reverse).

The forward operating power can vary depending on the destination within 368-736 k W with a corresponding change in the number of shaft revolutions between 1200 — 1640 rpm. The maximum reverse power is 184 ket at 750 rpm and the operating time is not more than 1 h .

The diesel crankcase is cast from aluminum alloy and consists of two parts. In the upper bearing part there are seven main bearing seats with inserts in which the crankshaft rotates. Detachable steel liners are filled with lead bronze and bore around the neck of the shaft. The working surface of the liners is covered with lead-tin alloy. Located at an angle of 60 °, the platforms of the upper part of the crankcase are used to install two six-cylinder blocks.

The crankshaft is made of nitrided alloy steel. He has six knees located

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

Cranks of an I-section are made of alloy steel.

The top 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 detachable: the cover is attached to the main connecting rod using a wedge with two conical pins. In the lower head of the main connecting rod, a steel liner filled with lead bronze is installed, consisting of two halves. The connecting rod is connected to the main connecting rod by means of a finger pressed into the eye of the main connecting rod.

Piston — stamped from aluminum alloy. The piston bottom is in the shape of a Hesselmann combustion chamber. On the piston there are grooves in which four piston rings are installed, of which two (upper) are compression and the rest are oil scraper. In the four recesses of the piston bottom are gas distribution valves. The piston pin is made of alloy steel, hollow, with a hardened outer surface, is pressed into the piston bosses.

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

Fig. 1. Diesel M-50F-3

Diesels of the M-400 type have two six-cylinder monoblocks (the head is cast at the same time as the cylinder block). In monoblocks, six cylinder bushes are pressed in, each of which is a connection of two pipes: the inner one is from alloy steel and the outer one is from carbon steel. The working surface of the inner pipe is nitrided.

The gas distribution mechanism is driven from the crankshaft by means of an inclined transmission located in 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. On each head of the block there are two distribution rollers, the cams of which directly act on the valve discs, interconnected by cylindrical gears.

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

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

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

The diesel regulator is an all-mode, indirect action, with an elastically connected cataract. It provides speed stability in the range from 500 to 1850 rpm.

Nozzle — closed type, with a hydraulically controlled needle. The atomizer nozzle has eight spray holes with a diameter of 0.35 mm, arranged so that when spraying fuel, a cone with an angle at the apex of 140 ° is formed. A fuel injection pressure of 200 bar ensures its atomization to the smallest particles uniformly distributed throughout the entire volume of compressed air in the combustion chamber.