Training Doc Mercedes 900

MTU Friedrichshafen GmbH | All rights reserved

Training Documentation

Mercedes-Benz Industrial Engines

Series 500, 460 und 900

MTU Trainingcenter


Table Of Contents

Page 46Piston

Page 43Unit pump removal and installation

Page 41Nozzle holder kombination removal and installation

Page 39Injection system

Page 36Valve drive

Page 30Cylinder head and gasket

Page 29Cylinder designation

Page 27Engine cross section

Page 26Technical features

Page 24Series 500 engine models

Page 23Emission standards

Page 22Mercedes-Benz Fluid and lubricant specification

Page 21Mercedes-Benz Engine Data Manual

Page 18Safty information

Page 9Tightening specifications

Page 8Information


Table Of Contents

Page 77Assessment cylinder liners

Page 74Air and exhaust ducting

Page 73Thermostat

Page 72Coolant distribution

Page 69Crankcase ventilation system

Page 67Engine oil and filter change

Page 64Components of the lubricating system

Page 62Oil cooler and filter housing

Page 58Fuel pre-filter

Page 57Fuel filter removal and installation

Page 55Fuel system

Page 52Cylinder liner

Page 51Crankcase

Page 50Connecting rod

Page 48Piston cooling


Table Of Contents



Page 101Fuel system


Page 98Crankcase



Page 43Piston




Page 30 and 91Valve drive





Page 84Series 460


Table Of Contents

Page 135Piston




Page 125Valve drive





Page 114Series 900 engine models



Page 111Thermostat






Table Of Contents



Page 155Thermostat







Page 141Fuel system


Page 138Crankcase




Table Of Contents

Page 188ADM-X

Page 187Engine Tests

Page 186Minidiag 2

Page 185Parameterization

Page 184Control loop (MR)

Page 182Oil level sensor

Page 181Temperature sensor characteristic

Page 180Rotary sensor

Page 179Rotational speed, crank angle and TDC detection

Page 178Sensors

Page 173Sensor overview series 900



Page 163Delivery phases of the unit pump

Page 161Injection control

Page 158Structure and priciple

Page 157Engine electronic controller (MR)

Page 192Special tools


Information

This documentation is for training purposes only.

All torques and procedures reflect the stand of now and have to be validated bevore use.

This Publication is protected by copyright and may not be used in any way whether in

whole or in part without the prior written permission of MTU Friedrichshafen GmbH.

This restriction also applies to copyright, distribution, translation, microfilming and storage

or processing on electronic systems including data bases and online services.

1.Edition 10.2010


Tightening specification for set screw and studconnections

Tightening specification for set screw and stud connections to works standard MTN 5008

This works standard applies to set screws subjected to little dynamic load as per MMN 384, DIN 912, EN 24014

(DIN 9311), EN 24017 (DIN 933), EN 28765 (DIN 960), EN 28676 (DIN 961), DIN 6912 and to studs as per DIN

833, DIN 835, DIN 836, DIN 938, DIN 939 and associated nuts.

They do not apply to heat-proof screws in the hot component area.

Tightening torques MA are for screws of strength class 8.8 (bright surface, phosphate coating or galvanised) and

10.9 (bright surface or with phosphate coating).

The values in the table are based on a friction coefficient tot = 0.125. Precondition: Thread and mating faces of

screws and nuts must be coated in engine oil prior to assembly.

When tightening manually (tightening specifications), an assembly tolerance of + 10% of the table values ispermitted for unavoidable deviations of the tightening torque from the table value during the tightening process e.g. resulting from inaccurate readings and overtightening during assembly.

When tightening mechanically, the permitted assembly tolerance is + 15 %

Tightening torques = MA


Tightening specification for set screw and studconnections


Tightening torques for plugs

Tightening torques for plugs prescribed in standard MTN 51831

This standard applies to plugs as per DIN 908, DIN 910 and DIN 7604 with screwed plug DIN 3852, model A (sealed

by sealing ring DIN 7603Cu).

DIN 908 DIN 910 DIN 7604A/C

Tightening torques MA are given for plugs made of steel (St) with surface protected by a phosphate coating and

oiled or galvanised.

Thread and mating faces beneath heads must be coated in engine oil prior to assembly.

An assembly tolerance of + 10% of the table values is permitted for unavoidable deviations of the tightening torque

from the table value during the tightening process e.g. resulting from inaccurate readings and overtightening during

assembly.



Tightening torques for plugs


Tightening torques for banjo screws

This standard applies to banjo screws as per MMN 223 and N 15011 sealed with sealing ring DIN 7603-Cu

Tightening torques MA are given for banjo screws made of steel (St) with surface protected by a phosphate coating

and oiled or galvanised and for banjo screws made of copper-aluminium alloys.

Thread and mating faces beneath heads must be coated in engine oil prior to assembly.

An assembly tolerance of + 10% of the table values is permitted for unavoidable deviations of the tightening torque

from the table value during the tightening process e.g. resulting from inaccurate readings and overtightening during

assembly.



Tightening torques for banjo screws


Torque specifications for union nuts

Torque specifications for union nuts as per DIN 3859-2

1 Union nut2 Union body3 O-ring4 Ball bushing

Union nut: When installing the ball bushing, the union nut should be tightened firmly by hand (noticeableincrease in force) a quarter of a turn (90) beyond this point.


Safety Instructions

These Safety Instructions must be read and followed by any persons operating, carrying out maintenance or repairs on the machineryplant.

General Safety and Accident Prevention RegulationsIn addition to the instructions in this publication, general safety and accident prevention regulations and laws must be taken into consideration; thesemay vary from country to country. This MTU engine is a state-of-the-art product and conforms with all the applicable specifications and regulations.Nevertheless, persons and property may be at risk in the event of: Incorrect use Servicing, maintenance and repair carried out by untrained members of staff Modifications or conversions Non-compliance with the safety instructionsCorrect UseThe engine is to be used solely for the purpose stated in the contract. Any other use is considered improper use. The manufacturer will accept noliability for any resultant damage. The responsibility is borne by the user alone.Correct use also includes observation of the Operating Instructions and Maintenance Manual and compliance with maintenance and repairinstructions.Personnel RequirementsWork on the engine must be carried out only by reliable personnel. The specified legal minimum age must be respected.Only fully trained or qualified personnel must be employed. Responsibilities of the operating, maintenance and repair personnel must be specified.Modifications or ConversionsModifications made by the customer to the engine may affect safety. No modifications or conversions must beimplemented without prior consent from DDC or MTU.We cannot accept liability for any damage resulting from unauthorised alterations made to the engine.Organisational MeasuresThe personnel must be instructed on engine operation and repair by means of the Maintenance Manual, and in particular the safety instructions mustbe explained. This is especially important for personnel who work on the engine only on an occasional basis.


Safety Instructions

Spare Parts

Spare parts must at least satisfy the requirements specified by the manufacturer. This is guaranteed when original components are used.

Working Clothes and Protective Equipment

Always wear protective shoes when working on plant. Select appropriate goggles for the work to be carried out. Always wear protective goggles whenworking with mallets, cutting tools, drift punches and similar tools.

Work clothing must be tight-fitting so that it does not catch on rotating or projecting components. Do not wear jewellery (e.g. rings, chains, etc.).

Transport

Lift the engine only with the lifting eyes provided. Use only the transport and lifting equipment approved by DDC/MTU.

The engine must only be transported in installation position.

Engine Operation

When the engine is running, ear protectors must always be worn in the engine room.The engine room must be well ventilated.

To avoid injuries caused by falling, leaked or spilt engine oil and coolant must be cleaned up immediately or absorbed with appropriate bondingagents. Exhaust gases from combustion engines are poisonous and injurious to health if inhaled. The exhaust pipework must be leak-free anddischarge exhaust gases to atmosphere. During engine operation, do not touch battery terminals, generator terminals or cables. Inadequateprotection of electrical components can lead to electric shocks and serious injuries.

Never disconnect coolant, oil, fuel, compressed air or hydraulic lines while the engine is running.

Maintenance and Repair

Compliance with maintenance and repair specifications is an important safety factor. Unless expressly permitted, no maintenance or repair work mustbe carried out with the engine running. The engine must be secured against inadvertent starting and the battery disconnected. Attach sign Do notoperate in operating area or to control equipment. Persons not involved must keep clear. Never attempt to rectify faults or carry out repairs if you donot have the necessary experience or special tools required. Maintenance work must only be carried out by authorised, qualified personnel.

Use only tools in perfect condition. Do not work on engines or components which are only held by lifting equipment or crane. Always support these

components on suitable frames or stands before beginning any maintenance or repair work. Before barring the engine, ensure that nobody is withinthe danger area. After working on the engine, check that all guards have been reinstalled and that all tools and loose components have beenremoved from the engine. Fluids emerging under high pressure can penetrate clothing and skin and may cause serious injury. Before starting

work, relieve pressure in systems and H.P. lines which are to be opened. Never bend a fuel line and do not install bent lines. Keep fuel injection linesand connections clean. Always seal connections with caps or covers if a line is removed or opened.


Safety Instructions

During maintenance or repair work, do not hit fuel lines with wrenches or other tools. To tighten connections when installing lines, use the correcttightening torque and ensure that all retainers and dampers are installed correctly. Ensure that all fuel injection lines and compressed oil lines havesufficient play to avoid contact with other components. Do not place fuel or oil lines near hot components.

Do not bend lines under pressure or use force. In order to avoid burning, take special care when placing hot components on products when workingwith hot liquids in pipelines, pipes and chambers. Until the engine has cooled, the breather cap must not be opened. Release the breather cap andallow pressure to escape before removing the cap. Take special care when removing ventilation or plugs from engine. In order to avoid beingsprayed with highly pressurised liquids, hold a cloth over the screw or plug. It is even more dangerous if the engine has recently

been shut down as the liquids may still be hot. Take special care when draining hot fluids risk of injury. Drain the fluids into a suitable container andwipe up any spillages. When changing engine oil or working on the fuel system, ensure that the engine room is adequately ventilated. When workinghigh on the engine, always use suitable ladders and work platforms. Make sure components are

placed on stable surfaces.To avoid damaging your back when lifting components weighing 25 kg (50 lb.) or more, use lifting gear or request aid fromother workers. Ensure that all chains, hooks, slings, etc. are in good condition, are sufficiently strong and that hooks are correctly positioned. Liftingeyes must not be unevenly loaded. When operating electrical equipment, certain components of this equipment are live. Non-compliance withwarning notices could result in serious physical injury or damage to property. Work must be carried out only by qualified personnel. Prior to workingon electrical equipment, switch off live units. Gases released from the battery are explosive. Avoid sparks and naked flames. Do not allow batteryacids to come into contact with skin or clothing. Wear protective goggles. Do not place tools on the battery. Before connecting the cable to thebattery, check battery polarity. Battery pole reversal may lead to injury through the sudden discharge of acid or bursting of the battery body. Do notdamage wiring during removal work and when reinstalling wiring and ensure that during operation it is not damaged by contact with sharp objects, byrubbing against another component or by a hot surface. Never connect wiring to a line which carries liquid. On completion of the maintenance andrepair work, any cables which have become loose must be correctly secured. Always tighten connectors with connector pliers. If cables are presentat mechanical components and there is a risk of wear, the cables must be retained in cable clamps. For this purpose, no cable straps must be usedas, during maintenance and/or repair work, the straps can be removed but not installed a second time. Check security of all plug-in connections. It isnot sufficient to tighten the connections by hand with a bayonet union. There is the risk of the lock not engaging properly and the connector comingloose during engine operation. Therefore pliers must be used for turning the bayonet union nut in clockwise direction.

Environmental ProtectionDispose of used fluids and lubricants and filters in accordance with local regulations. Manipulation of the injection or control system can influence the engineperformance and exhaust emissions. As a result, compliance with environmental regulations may no longer be guaranteed.


Mercedes Benz Engine Data Manual

https://motorenhandbuch.i.daimler.com


Mercedes-Benz Specifications for Operating Fluids

The MB BeVo provide you with anoverview of not only the requirementsfor the operating fluids, but also forthe recommended.

http://bevo.mercedes-benz.com/


Emission Standards HDDE >130KW


Series 500 Engine Models

Baureihe 500

V 6

OM 501 LA

V 8

OM 502 LA

VH = 12l VH = 16l

Series


OM 502 LA


Technical Features Series 500

Outstanding power output and torque characteristics over the whole rpm range

Dynamic start-off characteristics and pulling power

Attractive power/weight ratio

Low fuel consumption

High-pressure direct injection, pump-line-nozzle system with peak pressures up to 1,800 bar.

Electronic engine control (MR) with electronic system fixed to the engine, and extensive engine protection functions

Direct injection with centrally positioned injection nozzle.

4-valve technology

Useful engine brake rpm well over rated rpm, up to 2400 rpm

Meets the emission legislation of Euromot IIIa

Turbocharger with charge air cooling

Rated engine speed 1,800 rpm or 2000 rpm

Low maintenance requirement

Long maintenance intervals

Engine oil and fuel filter located at the front, for easy maintenance

Maintenance-free belt drive

Can run on FAME / RME (rape methyl ester) or biodiesel, and engine oil changes are halved

High reliability and long runtime

Low number of component variants, as many parts are the same on both 6 and 8 cylinder engines

Rear engine power take-off ex works


OM 502 LA Cross Section


Cylinder Designation

KSKGS

1 32

5

4

6 87


Cylinderhead

The Euromot IIIa engines are fitted with a modifiedcylinder head and therefore a new cylinder headgasket with increased elastomer thickness.The following bores in the base of the cylinderhead have been provided with countersinks with adepth of 1.0 mm:

Engine oil pressure side (OD) Engine oil return (OR) Coolant supply (WZ) Coolant return (WR)


Cylinderhead Gasket

On the cylinder head gasket, the elastomer sealing elements atthe following bores have been raised bythe dimension (X): Engine oil pressure side (OD) Engine oil return (OR) Coolant supply (WZ) Coolant return (WR)The sealing between the cylinder head and the crankcase isimproved because the elastomeric sealing elements are higher.Moreover, a fire shield (arrow) was vulcanized onto the coolantfeed hole (WZ). This fire shield (arrow) is an added protection forthe elastomeric sealing element in the event of a possible minorgas leak in the cylinder head gasket.

OD Engine oil pressure sideOR Engine oil returnWR Coolant returnWZ Coolant feedX Dimension


Cylinder Head with Inductively-hardened SealingSurface

As of engine end no. 263.000, the cylinder heads have been modified.The cylinder head sealing surface has been inductively hardened at fourpoints (arrows).This inductive hardening is visible by a slight increase in height at the fourpoints (arrows). This increases the contact pressure on the cylinder headgasket.

Repair information:Cylinder head sealing surfaces with the four inductively hardened points(arrows) may only be visually checked for flatness in the sections where thereare no raised areas due to inductive hardening.The cylinder head generally has to be exchanged if there is any distortion tothe cylinder head or wear to the cylinder head sealing surface caused by thebeaded cylinder head gasket, otherwise a seal between the cylinder headand crankcase cannot be ensured.The cylinder head sealing surface may not be reworked (ground).


Cylinder Head

Coolant

Engine Oil

Charge Air

Exhaust

Fuel

Fuel Return / Leak Off


Cylinder Head Mounting

The cylinder head is tightened in 6 stages.The cylinder head bolts do not requireretightening.

Moisten the bolts with engine oil!

1. Stage 10 Nm2. Stage 50 Nm3. Stage 100 Nm4. Stage 200 Nm5. Stage 90 6. Stage 90

The maximum shank length of 212 mm is not to be exceeded !

31

4 2L


Notes


Valve Drive

Gas exchange is improved by 4-valve technology, thuscontributing considerably to lower fuel consumption with loweremissions. The intake and exhaust valves are controlled bymeans of roller tappets, push rods and intake and exhaustrocker arms which are set in a groove in the crankcase with asliding block, and which operate the intake/exhaust valvepairs through a valve bridge.

The rocker arm spindle complete with preassembled rockerarms and rocker arm bearing bracket is bolted to the cylinderhead. To keep wear in the whole valve assembly to aminimum throughout ist lifetime, the contact surfaces of thevalve, valve bridge, the rocker arm thumb, the upset ballsocket of the push rod, and the ball head of the adjustingscrew, are induction hardened. This is to allow them tosupport the actuation forces of the high-temperature valvesprings, and the effects of inertial forces and cylinderpressures.


Valve Adjustment

Checking valve clearance at two crankshaftpositions1. Check TDC position of piston in cylinder A1:

If the rocker arms are not under load on cylinder A1,the piston is in firing TDC.If the rocker arms are under load on cylinder A1,the piston is in overlap TDC.

2. Check valve clearance with cold engine: Inlet = 0.4 mm; Exhaust = 0.6 mm;

3. Check all valve clearances at two crankshaft positions(firing and overlap TDC for cylinder A1) as per diagram.

4. Use feeler gauge to determine the distance between valvebridge and rocker arm.

5. If the deviation from the reference value exceeds+ 0.2 mm / -0.1 mm, adjust valve clearance.

Adjusting valve clearance1. Loosen locknut (1) and unscrew

adjusting screw (2) by a few threads.2. Insert feeler gauge between valve

bridge and rocker arm.3. Readjust adjusting screw (2) so that

the feeler gauge just passes throughthe gap.

4. Tighten locknut (1) to 50 Nm, holdingadjusting screw (2) firmly.

5. Check if the feeler gauge just passesthrough between valve bridge androcker arm.

Result: If not, adjust valve clearance.


Notes


Pump-Line-Nozzle Injection System (PLD)

The injection process is performed by the pump-line-nozzle (PLD) system, controlled by an electronicengine management system

In the PLD system, fuel is delivered to the injectionnozzle by individual unit pumps over short, rigidhigh-pressure injection lines, and through thepressure pipe connection screwed into the cylinderhead.

The connection to the nozzle and nozzle holder islocated centrally at the cylinder, and is integratedwith, and removable from, the cylinder head.

A unit pump fitted for each cylinder is locateddirectly on the crankcase.


Pressure Pipe Connection And Nozzle Holder Location

Connection to the nozzle holder and injectionnozzle (positioned vertically at the center of thecylinder), is through a fixed, preassembledpressure pipe connection with integral pin-typefilter.

The nozzle holder with injection nozzle is heldin a protective sleeve by means of a clampingclaw supported on the nozzle holder andconstant throttle cap, and attached with acentral screw.

The seal at the nozzle protective sleeveconsists of a copper sealing sleeve.

For nozzle holder positioning, the clampingclaw grips a locating pin fixed into the nozzleholder cap.

The pressure pipe connection is attached witha press-in ball fastening.

1 Injection line, 30 Nm2 Pressuer screw, 40 Nm3 O-Ring4 Pressure pipe connection5 Nozzle holder combination6 O-Ring7 Screw, 50 Nm, 91 mm8 Clamping claw9 Constant throttle cap

1 2 3 4 5

7

68

9


Removing The Nozzle Holder Combination

Injector removal

1. Remove fuel leak line.

2. Remove fuel line (3).

3. Remove thrust screw (2).

4. Pull off pressure pipe neck (1).

5. Remove screw (4).

6. Take off clamp (5).

7. Screw impact extractor (6) into injector.

8. Remove injector using the impact extractor.

9. If necessary remove sealing sleeve with

extractor (7) from cylinder head.

10. Seal all openings with appropriate covers

after removal.

54

67


Installing The Nozzle Holder Combination

54

7

8

1. Measure the shank length of screw (4) (max 91 mm)

2. Insert a new O-ring at nozzle holder combination

3. Press new sealing sleeve (8) with special tool (7)

onto nozzle holder combination

4. Install nozzle holder combination

5. Mount the retaining clip (5), 50Nm

6. Place the new O-ring at pressure pipe connection (1)

7. Fit the pressure pipe connection (1) and tighten pressure

screw (2),40 Nm. Moisten the pressure pipe connection

around the taper seal with engine oil.

8. Install the injection line (3)


Injection Pump Removal

Injection pump removal

1. Disconnect wiring (1) from injection pump.2. Remove fuel line (2).3. Unscrew securing screws of injection pump by

approx. 10 mm.

The preloaded compression spring presses theinjection pump out of the crankcase. If not use specialtool (6)and carefully extract pump.

4. Remove injection pump securing screws.5. Remove injection pump.6. Remove sealing rings from injection pump.7. Seal all openings with appropriate covers after removal.

6


Injection Pump Installation

Injection pump installation

1. Remove all covers from openings2. Coat the new o-rings with lubricating grease, and install

them with tool (3).Note: The black o-ring must be allways on top!

3. Carefully clear any dirt or paint residues away from thesealing surface of the MR/PLD unit pump and the crankcase.

4. Carefully press the MR/PLD unit pump in by hand.If the unit pump cam is up at the camshaft, turn the engine.

5. Install the bolts and tighten to 65Nm.6. Install injection line (2) and tighten to 30Nm.7. Connect wiring (1) (1,5 Nm).8. If pump has been changed, new pump code must be

programed via the MiniDiag2.

3


Notes


Piston

Pistons and piston rings are among the most highly stressed enginecomponents. Pistons are therefore constructed of high-temperaturealuminum alloy.

The piston top land and stem are graphite-coated to increase running-in and limp-home capability.

There is a cast-in, reinforced ring groove for the first piston ring.The piston pin support is trapezoidal in shape, to increase thepressure-load surfaces on the piston and connecting rod.

Features of the piston rings:Groove 1: Compression ring

Cast-iron keystone ring with plasma spray layer ofchromeceramic, spherical-lapped.

Groove 2: Compression ring with oil-scraper action.Chrome-plated taper-faced ring with internal angleunderneath.

Groove 3: Oil scraper ringRoof bevel ring with chrome-plated, lapped lands andgarter springs.


Piston Changes For Euromot 3A

New combustion process with W- Piston:

- higher stability

- less carbon build up

old new


Piston Cooling

Due to the piston's increased cooling requirements and additionalcamshaft oiling, the oil spray nozzle on the Euromot IIIa engine hasa higher oil throughput. This also necessitates modifications to theoil pump.

The spray direction of the oil spray nozzle for the piston has beenchanged to coaxial oil spraying, which sprays into the undivided,fluted cooling duct in the piston. Due to this modification, pistoncooling is improved as a result of increased engine oil throughput.The oil spray nozzle's pipe diameter has been increased to 4 mm,and the diameter at the outlet aperture at the end of the nozzle hasbeen calibrated to 3 mm. Due to this modification, the oil spraynozzle has a higher oil throughput, and the oil spray fans out less,leading to better piston cooling.

The base of the oil spray nozzle has threebores (arrows) for oiling the intake, exhaustand unit pump cams on the camshaft.


Notes


Connecting Rod

The steel connecting rod is partially forged. Theseparation of connecting rod from bearing cap ismade by 'cracking'.

Compared with the conventional, costly separatingprocess, 'cracking' brings high dimensionalstability to the large connecting rod eye. Four laser-structured surfaces have additionally been applied.These improve the bearing shells' anti-twistprotection. The separation point at the largeconnecting rod eye is set obliquely.

Connecting rod and bearing cap are linkedpositively and frictionally with each other by twostretch-thread bolts.

The ignition power is absorbed evenly at the small,trapezoidal connecting rod eye by a solid bronzebushing. Two oil holes have been made in theconnecting rod eye for the oil supply to the smallend bearing.


Crankcase

Design features:

Compact design, by integrating the oil cooler, coolant pump coil,unit pumps, and the coolant, fuel and oil ducts.

Highly rigid alloy cast iron.

Rigid crankcase deck and stable liner bottom collar support, withlow-set threads on the cylinder head bolts. This results in low-warp absorption of the thread connection and ignition forces bythe rigid collar of the wet cylinder liner.

Rigid side walls extending well below the center of thecrankshaft, and bolted together with the crankshaft bearing caps.

With new vermicular graphite cast iron (GGV) material onOM 501 diesel engines with more than 300 kW (408 hp) andon OM 502 diesels with 405 kW (551 hp) and more.


Cylinder Liners

old new

The cylinder liner has been fitted with an oil scraper ring toprevent carbon buildup. The oil scraper ring replaces theinduction hardening in the upper part of the cylinder liner.

Piston

Scraper ring

Crankcase

Sealing ring

Cylinder liner


Cylinder Liners

The cylinder liner (2) has been fitted with an oilscraper ring (3) to prevent carbon buildup. Thechrome-molybdenum (CrMo) oil scraper ring (3)has a height of 13.5 mm and a projection of 0.15mm to the inner diameter of the cylinder barrel inthe cylinder liner (2). The oil scraper ring (3)replaces induction hardening in the upper part ofthe cylinder liner (2).

The oil scraper ring's (3) projection reducescarbon deposits on the top land of the piston(area from the piston crown to the first piston ringgroove). This reduces wear on the cylinder barrelof the cylinder liner (2).

2 Cylinder liner3 Oil scraper ring4 Sealing ring

The outside diameter on the liner collar has been enlarged to improve the fit of the cylinder liner (2) in the cylinder crankcase.The sealing ring (4) between the collar of the cylinder liner (2) and the cylinder crankcase is made of stainless steel (X5CrNi 18-10) and has a largeroutside diameter than the tombac ring used previously. This results in higher abrasion resistance, reduced wear and improved installation reliability forthe sealing ring (4).Due to the oil scraper ring (3) in the cylinder liner (2), an assembly tool is required to install the pistons.


Notes


Fuel System


Fuel System

The low-pressure fuel system has been specially designed to meet the requirements of the high-pressure injection system with individual unit pumpson V-engines. Unlike on conventional injection systems, to ensure stable injection, a high pre-pressure is necessary in the low-pressure system anda large flush volume for cooling the control valve solenoids in the unit pumps.

1 Fuel tank1.1 Fuel strainer (800 m)2 Fuel prefilter (KVF 300 m) with manual fuel feed pump3.1 Plug-on valve in fuel feed (locked open)3.2 Plug-on valve in fuel return (locked open)4. Fuel heat exchanger5. Fuel pump (KFP)5.1 Pressure relief valve (9.0 - 12.0 bar)6. Fuel filter (5 m)6.1 Fuel filter drain valve6.2 Constant vent in fuel filter (0.7 mm)7. Nozzle holder combination8. PLD unit pumps (Y6 to Y13)9. Banjo union with constant vent (0.7 mm)10. Overflow valve (2.0 bar up to engine No. 092 407, 2.65 bar from

engine No. 092 408)10.1 Throttle (3.1 mm) in overflow valve11.1 Fuel feed connector (in frame)11.2 Fuel return connector (in frame)12 Throttle (0.5 mm) in flame starting system fuel lineB10 Fuel temperature sensorR3 Flame glow plugY5 Flame starting system solenoid valve

Test pointsI Fuel pressure after fuel filter

Idle speed: 1.8 - 2.8 bar up to engine No. 092407, 2.2 3.2bar from engine No. 092 408Cutoff speed: 4.5 5.5 bar

II Fuel pressure after fuel pumpIdle speed: 2.1 3.0 barCutoff speed: 5.0 6.0 bar (limit value 6,5 bar)

III Fuel intake pressure before fuel pumpCutoff speed: -0.35 to -0.25 bar

IV Fuel return quantity at fuel tankIdle speed: 0.6 1.0 l/minCutoff speed: 1.0 -1.6 l/minLow pressure-fuel system leaktightnessTest pressure 5.5 bar/test period 5 minutes: no pressure drop

V Fuel return quantity at nozzle holder combinationIdle speed: oil-dampCutoff speed: drops only at most.


Fuel Filter

Filter removal:

1. Unscrew the fuel filter screw cap.Only remove screw cap with filter insert about 1 cm. After thefuel has run out remove filter from the housing.

2. Remove the filter insert from the cap by pressing at the side of thefilter.

Filter installation:

1. Replace the sealing ring2. Insert new filter element in screw cap3. Screw on the screw cap with filter element, and tighten.

Torque value writen on cap3. Start the engine and bleed the fuel system.4. Check the filter for leaktightness with the engine running.


Fuel prefilter with heated water separator

In countries where the fuel is considered to be heavilycontaminated and to have a high water content, an additionalfuel filter with integrated water separator (including manualfeed pump) is highly recommended.

Engines that are operated in countries of EasternEurope, or filled with fuel from those countries, mustbe fitted with a prefilter.

Advantages to the customer:

Increased durability of the injection system Long maintenance intervals despite difficult operating

conditions Greater economy through shorter vehicle downtimes


Fuel prefilter with heated water separator

Filter removal:

1. Place a buket under the prefilter2. Open the drain valve (10) and bleed screw (6) Let the filter

element (2) run dry Dispose of the water/fuel mixture in env.acceptable manner.

3. Pull out the heater plug (9)4. Unscrew filter element (2)5. Unscrew the separator (3) from the filter element (2). If damaged,

replace the separator6. Clean the separator (3) Ensure that the sealing ring groove is

clean!

Filter installation:

1. Moisten the new sealing rings with engine oil.2. Screw the separator (3) with new sealing ring (8) onto the filter

element (2) and finger-tighten.3. Screw the filter element (2) with new sealing ring onto filter

head (1) and finger-tighten. Do not use tools to tighten!4. Close drain valve (10).5. Fill the prefilter with a manual fuel feed pump (5).6. Close the bleed screw (6).7. Start the engine and bleed the fuel system. Let the engine run for

about 1 minute. The fuel system is bled automatically.8. Check the prefilter for leaktightness.

10

3

5

9

6

2

1


Checking The Fuel System

In what circumstances must the fuel pressure be checked?Poor startup, poor performance

What can cause the fuel pressure to be too low?Dirty prefilter, dirty fuel filter, faulty overflow valve, fuel system is drawing in air, kink in feed line from tank, intake line atfuel tank sensor, check valve in fuel feed, leak in filter bowl at the return flow, faulty feed pump

What can cause the fuel pressure to be too high?Faulty overflow valve, kink in return flow line, check valve in the fuel return line, fuel tank sensor clogged

What other operations should be carried out?Check the fuel system at and in the engine for leaktightness, check the fuel intake pressure, measure the fuel returnquantity and check for air bubbles.


Notes


Oil Cooler And Oil Filter Housing

The most important components of theengine lubrication / cooling system are:

- Oil pan- Oil pump with pressure relief valve- Oil retention valve (return flow check valve)- Oil/water heat exchanger- Oil filter with drain valve and filling valve- Filter bypass valve- Main oil duct, oil ducts and oil lines- Oil spray nozzles- Oil temperature sensor and oil pressure

sensor- Oil level sensor- Rocker arm spindle, rocker arm with oil hole


The following components are integrated in thealuminum die-cast housing of this assembly:

1 Oil filter2 Oil temperatur sensor3 Oil pressure sensor4 Coolant temperatur sensor5 Connection for oil filling

1

53

2

4

6 Filter bypass valve(opening pressure 2,3...3,0bar)

7 Oil/water heat exchanger8 Filter drain valve

86

7

Oil Cooler And Oil Filter Housing - Components


Components Of The Lubricating System

Oil pumpThe oil pump is in the form of a gear type oil pump. The gear type oil pump is located at the rear of the crankcase. The oil pump is driven by thecrankshaft. It delivers the engine oil from the oil pan through an oil duct to the oil retention valve, then to the lateral main oil duct and the oil/water heatexchanger.

Pressure relief valveThe pressure relief valve is located under the oil pump and maintains constant oil pressure. If too much oil is delivered at high engine speeds, thepressure relief valve opens and allows the engine oil to flow directly from the oil pump back to the oil pan.

Oil retention valve (return flow check valve)The return flow check valve is placed at the right rear in the crankcase and is intended to prevent engine oil flowing back into the oil pan when theengine is stopped. The oil ducts are therefore always filled with oil. When the engine is restarted, this ensures that components always receiveoptimal lubrication from the beginning.

Oil/water heat exchangerThe oil/water heat exchanger is located in a housing assembly on the front of the crankcase, with integral oil/water heat exchanger and oil filter.The engine oil flows through the plates in the oil/water heat exchanger, and these are washed around by the engine coolant. Since the engine coolantis at a considerably lower temperature than the engine oil, the coolant absorbs the heat from the engine oil and cools it down to engine operatingtemperature. During cold starts, the engine oil is warmed up by the surrounding coolant through of the oil/water heat exchanger.

Oil ducts and oil linesOil ducts are integrated into the crankcase and cylinder heads. The oil pressure and oil return lines to the turbocharger are located externally.The oil retention valve is located at the start of the lateral main oil duct, which is placed on the right of the crankcase. From two further oil ductslocated centrally at camshaft level in the crankcase, other oil ducts (Y and cross-drillings) go to the individual oil spray nozzles, camshaft bearing,crankshaft main bearing, MR/PLD unit pumps and the individual cylinder heads. Engine oil is fed from the main oil duct, through an oil duct system inthe rear wall of the crankcase, to the turbocharger oil pressure line and both compressor bearings. The oil ducts in the crankcase are partly closedwith screw plugs or balls.



The connecting rod bearing is supplied with engine oil through oil ducts integrated into the crankshaft. Engine oil is delivered to the bearing bracketsof the individual rocker arm spindles through holes in the cylinder head gasket and the oil duct in the cylinder head. From the rocker arm spindlebearing bracket, oil is supplied to the rocker arm spindle and all the rocker arms. It then passes through the oil holes in the rocker arms and alsosupplies the valve assembly. The oil then flows back to the oil pan through oil return holes in the cylinder head and crankcase.

Oil filterThe oil filter housing is fitted to the left front of the crankcase. It contains an oil filter insert, made of paper. The oil filter insert is clipped into the oil filtercover and is replaced from the top. When the filter cover is unscrewed, engine oil in the filter housing flows through the drain valve back into the oilpan.

Drain valveThe drain valve is located in the oil filter housing under the filter insert, and opens when the filter cover isunscrewed. This ensures a cleaner filter change and less environmental pollution by reducing the amountof residual oil in the old filter.

Filter bypass valveThe filter bypass valve (release pressure 2. 3 - 3. 0 bar) is located in the housing assembly under the oil/water heat exchanger and connected with theoil filter through an oil duct. The normal position of the filter bypass valve is closed. If the oil filter insert is clogged, the pressure increase in the filterhousing opens the filter bypass valve. This ensures that the engine is lubricated, although the engine oil passing through the bypass valve isunfiltered.

Filling valveThe filling valve is placed at the bottom of oil filter housing and is closed with a screw plug (M33x2). Through this valve, engine oil can be poured intothe engine assembly, and after repairs to the engine oil system before starting the engine.



Oil spray nozzlesThe oil spray nozzles are located in the crankcase, one per cylinder. Oil is supplied to the oil spray nozzles through both oil ducts. The nozzles sprayengine oil continuously under the piston crowns, thus cooling them, while at the same time the piston crowns are lubricated by engine oil drippingthrough an opening in the top of the connecting rod. The oil spray nozzles also spray engine oil through another hole onto the valve and unit pumpcams on the camshaft.

Oil temperature sensor and oil pressure sensorThe oil temperature and oil pressure sensor is screwed from the front into the housing assembly under the oil/water heat exchanger, and connectedwith the oil filter through an oil return duct.


Eingine Oil And Filter Change

Only change the engine oil with the engine warm!

1. Unscrew oil filter cap approx. 1cm, filter housing will then train empty. When housing is empty, remove filter fromfrom cap by pressing at the side of the filter

2. Replace o-ring and insert new filter in cap. Tighten cap with specified torque (writen on cap)3. Drain off the engine oil at the oil drain plug on the oil pan. Fit new sealing ring to the oil drain plug.4. Screw in the oil drain plug and tighten.

Drain plug on oil pan Light alloy M20x1,5 60 NmM26x1,5 80 Nm

Plastic without steel insert 40 Nmwith steel insert 60 Nm

5. Pour in the specified quantity and quality of engine oil at the oil filler plug.Mercedes Benz BeVo http://bevo.mercedes-benz.com

6. Start engine Watch the engine oil pressure gauge! It should indicate pressure after several seconds.Do not rev the engine until oil pressure is indicated.

7. Allow the engine to run for 1 - 2 min at idle speed, once the oil pressure is indicated.8. Wait for about 5 minutes, then check the oil level and adjust if necessary. The waiting time must be observed.9. Check the oil filter, the oil pan drain plug if necessary, and the long-life oil filter for leaktightness.


Notes


Crankcase Ventilation System

Cyclone separator functional principle

The blow-by gases from the crankcase are sent as pre-cleaned crudegases to the cyclone separator insert (1).The cyclone separator insert (1) is made up of two cyclones.

The crude gas enters the cyclone from the side (tangentially). The gasstream is forced into a downwards spiral movement in the entrychamber. This causes the floating oil particles to be pitched towards thewall of the cyclone by the centrifugal forces and then slide down thetapered surfaces of the swirl chamber due to gravity and thedownwards movement of the gas. The oil comes out through a hole (2)at the lowest point of the cyclone.

As the cyclone tapers towards the bottom, the circumferential speedand centrifugal effect becomes greater so that finer particles can beseparated in the lower section.

At the lowest point of the cyclone the whirling gas reverses directionand goes back up and the clean gas is guided out through an outletpipe (3) (take-off tube) at the top.

The diameter and tapered form of the take-off tube determine thepressure loss and separation quality of the cyclone. A vacuumdiaphragm (5) controls the pressure in the engine oil gallery.The bypass valve (4) opens up with a high gas flow.

1

2

3

4

5



Crude gas entry Clean gas outlet

Oil return


Notes


Coolant Distribution

Internal water guide

Coolant is delivered from the water pump coil integratedinto the front of the crankcase, and flows through theplate-type oil cooler in the oil filter housing, which projectsinto the central water channel.From the central water channel in the crankcase, eachcylinder is supplied with water uniformly throughindividual, tangential water channels. The water flowaround the cylinder liners is divided in two by a fin. Thisensures the coolant flow in the lower cylinder area and aneven main flow in the upper area, for intensive cooling ofthe piston TDC areas where the thermal load is high.Coolant flows through the drillings in the crankcase intothe cylinder head. Particularly intensive cooling of thevalve lands and nozzle area is achieved by specialforming of the water jacket in the cylinder head.

Coolant flows back through openings in the crankcase into two return channels cast into the crankcase, one per cylinderbank. The return channels are connected to a cross-duct integrated in the oil filter/oil cooler housing assembly, throughwhich coolant flows back into the double thermostat housing joined to the coolant pump.


Thermostat Location

The installation location of the thermostats isshown on the right illustration.The circles point to the bleed tabs.These tabs must point upwards.

The standard thermostat starts to open at 83C.

Coolant must be changed in regularintervals.

See also maintenance bookletand BeVo


Air And Exhaust Ducting

from air filter

to charge aircooler

from charge aircooler

AirExhaust



On some engines, exhaust pipes with imprinted arrowsare used.

The arrow imprint must point towards the turbochargersupport!

Parts must be assembled free of tension and a tighteningtorque of 50 Nm must be applied.


Notes


Cylinder Liner Assessment

Matt gray surface, honing pattern visible, dry cylinderbarrel, without oil residues, without shining areas orreflecting areas of smoothness. There should not be anyburn marks or streaks on the cylinder barrels or liners.Individual, slight drawing scores are non-critical.The honing pattern is more or less clearly recognizableover the cylinder barrel. At the reversal point of the pistonring, the honing pattern may be partially eroded.

The cylinder liner or the crankcase can be reused.



With engines 904.9, 906.9 only

The stripe profile (arrows) in the upper area of the cylinderbarrel arises due to induction hardening on production ofthe crankcase, and is to be regarded as the normalcondition.

The longer the engine's operating time, the less visible thestripe pattern becomes.



The following applies if carbon is present inthe top land area:Clean the top land area and reuse thecylinder liner.Additionally remove the piston and assess thepiston rings.

The following applies if individual, continuousscratches or score marks are present:

The cylinder liner can be reused if slight scratches orscore marks are present.



The following applies if ring shaped depressions arepresent at the upper and lower piston ring reversal pointwith visible color shadings (arrow), but the honing patterncan still be recognized:

The cylinder liner or the crankcase can be reused.

The following applies in the case of pressure sheen marksand smoothness, e.g. individual, bare areas (arrow) in thecylinder barrel or allround indentations at the upper and lowerpiston ring reversal point:

The cylinder liner must be replaced.



The following applies in the case of imperceptible dryfriction marks or deposits (arrow) on the cylinder barrelrunning downwards from the 2nd or 3rd piston ring:

The cylinder liner is unusable and must be replaced.The piston should also be replaced.

The following applies if the honing pattern is only barely or notvisible or there is a perceptible wear step at the upperreversal point of the first piston ring (arrow):

The cylinder liner is unusable and must be replaced.



Only series 900

If the model series 900 engine reveals no inenginecomplaints, e.g. noises or increased engine oilconsumption, the crankcase can be reused.


Notes


Series 460

6-Zylinder Reihenmotor

OM 457 LA

Baureihe 457

VH = 12l

Series 460

OM 460 LA

6-Cylinder in line engine


OM 460 LA



High-strength, noise-optimised cylinder housing of high-additive cast iron. Compact design and high functional reliability through integration of the oil cooler, the unit pumps, and the coolant, fuel

and oil ports into the crankcase. Engines in three different power categories, which already correspond to the EURO III or Euromot/EPA Level 2 standard

from the start of production. Highly rigid oil pan of light alloy. Seven-journal crankshaft with counterweights bolted on. Induction-hardened bearing points and fillet radius. Fitted bearing located at the central bearing support for technical reasons related to vibrations. Crankshaft seal of radial sealing rings with nonwoven dust lip. Camshaft drive through flywheel side gear drive. Fuel delivery pump driven by a camshaft on the belt side. Oil pump in the oil pan, driven by gears on the flywheel side. Maintenance free poly-V-belt drive for all assemblies. Planetary gear drive starter on right at the flywheel. MR control unit with additional fuel cooler. Intake valve seat rings of Tribaloy, a high-carbon tungsten/steel alloy. These have to be smoothed when installed. Piston cooling though oil spray nozzles. Camshaft/unit pump lubrication through additional oil spray nozzles. Four-valve technology with 2 intake and 2 exhaust valves per cylinder. MR engine control with the engine electronics located directly on the engine. Pump-line-nozzle system with solenoid-controlled unit pumps. Electronically controlled high-pressure direct injection at 1800 bar. Direct injection with centrally positioned injection nozzle. Turbocharger with charge air cooling. Engine power take-off at rear, also possible at front by means of additional belt drive for ancillary assemblies (special

equipment). Can operate with biodiesel (RME).



KSKGS1 2 3 4 5 6


Information

The following components are in funktion and handling similar to the series 500, thereforethey are not dicribed in detail under the section Series 460

Dimensions and part numbers can deviate from the series 500.

Fuel filter & Fuel filter change

Page 57

Cylinder liner

Page 52

Cylinder liner assessment

Page 77

Piston

Page 46


Page 69

Nozzle holder kombination

Page 39

Engine oil and filter change

Page 67

Unit pump

Page 43

Fuel pre filter & Fuel pre filter change

Page 58

Cylinder head

Page 30 and 91


Cylinder Head

1

2

Main difference to serie 500

1 Coolant vent bore

2 Bolt pattern and bolts(Series 500 M18x2 / Series 460 M15x2)






The maximum shank length of 212 mm is not to be exceeded !

31

4 2L


Notes


Valve Drive

Gas exchange is improved by 4-valve technology, thuscontributing considerably to lower fuel consumption with loweremissions.

The intake and exhaust valves are controlled by means of rollertappets, push rods and intake and exhaust rocker arms whichare set in a groove in the crankcase with a sliding block, andwhich operate the intake/exhaust valvepairs through a valve bridge.

The rocker arm spindle complete with preassembled rocker armsand rocker arm bearing bracket is bolted to the cylinder head. Tokeep wear in the whole valve assembly to a minimum throughoutist lifetime, the contact surfaces of the valve, valve bridge, therocker arm thumb, the upset ball socket of the push rod, and theball head of the adjusting screw, are induction hardened. This isto allow them to support the actuation forces of the high-temperature valve springs, and the effects of inertial forces andcylinder pressures.


Valve Adjustment














I / E

I E I E

E I E I

I / E


Notes


Piston Cooling

Unlike the familiar BR 500, the 460 model series has two oilspray nozzles per cylinder. One of these (on the right indirection of travel) performs the traditional task of pistoncooling, while the other is placed separately (on the left inthe direction of travel) and has the task of lubricatingthe camshaft.

Note:It is not permitted to adjust the oil spray nozzle.The oil splasher pipe is soldered in, and the adjustmentprocess could cause initial damage.


Connecting Rod

The steel connecting rod is partially forged. The

The separation point at the large connecting rod eyeis set obliquely.

Connecting rod and bearing cap are linkedpositively and frictionally with each other by twostretch-thread bolts.

The ignition power is absorbed evenly at the small,trapezoidal connecting rod eye by a solid bronzebushing. Two oil holes have been made in theconnecting rod eye for the oil supply to the smallend bearing.


Crankcase

The crankcase is made of high-additive cast iron. This givesit a high level of strength and stability, while producing lowernoise emissions.

The side walls of the crankcase extend well below thecenter of the crankshaft. This gives it even greater rigidity.Integration of the oil cooler, the unit pumps, and the coolantand fuel ports into the crankcase, gives the engine a verycompact design.

Exchangeable wet cylinder liners are used.

On the left on the flywheel side, an assembling lug isprovided for attaching the compressor coupled with thepower steering pump.


Notes


Fuel System


Fuel System

1 Fuel tank R3 Flame glow plug1.1 Fuel strainer (800 m) Y5 Flame starting system solenoid valve1.2 Air admission valve2 Manual fuel feed pump2.1 "RACOR" fuel prefilter (special equipment3.1 Plug-on valve in fuel feed (locked open) A Fuel feed /intake vacuum side3.2 Plug-on valve in fuel return (locked open) B Fuel feed / pressure side4 Fuel heat exchanger C Fuel high pressure side (injection line) after PLD unit pumps5 Fuel pump D Fuel return after unit pump / leak fuel5.1 Pressure relief valve (7.0 - 8.0 bar) E Fuel flush quantity (fuel short circuit)6 Fuel filter (KF 3 m)6.1 Fuel filter drain valve6.2 Constant balance hole7 Nozzle holder combination8 PLD unit pumps (Y6 to Y11)10 Overflow valve10.1 Throttle in overflow valve (banjo bolt)12 Throttle in flame starting system fuel line


Checking The Fuel System

In what circumstances must the fuel pressure be checked?Poor startup, poor performance

What can cause the fuel pressure to be too low?Dirty prefilter, dirty fuel filter, faulty overflow valve, fuel system is drawing in air, kink in feed line from tank, intake line atfuel tank sensor, check valve in fuel feed, leak in filter bowl at the return flow, faulty feed pump

What can cause the fuel pressure to be too high?Faulty overflow valve, kink in return flow line, check valve in the fuel return line, fuel tank sensor clogged

What other operations should be carried out?Check the fuel system at and in the engine for leaktightness, check the fuel intake pressure, measure the fuel returnquantity and check for air bubbles.


Notes


Oil Cooler And Filter Housing

The most important components of theengine lubrication / cooling system are:

- Oil pan- Oil pump with pressure relief valve- Oil retention valve (return flow check valve)- Oil/water heat exchanger- Oil filter with drain valve and filling valve- Filter bypass valve- Main oil duct, oil ducts and oil lines- Oil spray nozzles- Oil temperature sensor and oil pressure

sensor- Oil level sensor- Rocker arm spindle, rocker arm with oil hole


Oil Cooler And Oil Filter Housing - Components

1

2

3

4

5 67

7

The following components are integrated in thealuminum die-cast housing of this assembly:

1 Oil filter2 Oil temperatur and pressure sensor3 Connection for oil filling4 Filter bypass valve5 Oil/water heat exchanger6 Filter drain valve7 Oil retention valve



Oil pumpThe oil pump is in the form of a gear type oil pump. The gear type oil pump is located at the rear of the crankcase. The oil pump is driven by thecrankshaft. It delivers the engine oil from the oil pan through an oil duct to the oil retention valve, then to the oil/water heat exchanger.

Pressure relief valveThe pressure relief valve is located under the oil pump and maintains constant oil pressure. If too much oil is delivered at high engine speeds, thepressure relief valve opens and allows the engine oil to flow directly from the oil pump back to the oil pan.

Oil retention valve (return flow check valve)The return flow check valve is placed in the oil cooler and filter housing and is intended to prevent engine oil flowing back into the oil pan when theengine is stopped. The oil ducts are therefore always filled with oil. When the engine is restarted, this ensures that components always receiveoptimal lubrication from the beginning.

Oil/water heat exchangerThe oil/water heat exchanger is located in a housing assembly on the left side of the crankcase, with integral oil/water heat exchanger and oil filter.The engine oil flows through the plates in the oil/water heat exchanger, and these are washed around by the engine coolant. Since the engine coolantis at a considerably lower temperature than the engine oil, the coolant absorbs the heat from the engine oil and cools it down to engine operatingtemperature. During cold starts, the engine oil is warmed up by the surrounding coolant through of the oil/water heat exchanger.

Oil ducts and oil linesOil ducts are integrated into the crankcase and cylinder heads. The oil pressure and oil return lines to the turbocharger are located externally.The oil retention valve is located in the oil cooler and filter housing, which is placed on the left side of the crankcase. From the oil duct located on theleft side of the crankcase, the oil ducts goes to the individual oil spray nozzles, camshaft bearing, crankshaft main bearing, MR/PLD unit pumps andthe individual cylinder heads. Engine oil is fed to the turbocharger oil pressure line and both compressor bearings. The oil ducts in the crankcase arepartly closed with screw plugs or balls.



The connecting rod bearing is supplied with engine oil through oil ducts integrated into the crankshaft. Engine oil is delivered to the bearing bracketsof the individual rocker arm spindles through holes in the cylinder head gasket and the oil duct in the cylinder head. From the rocker arm spindlebearing bracket, oil is supplied to the rocker arm spindle and all the rocker arms. It then passes through the oil holes in the rocker arms and alsosupplies the valve assembly. The oil then flows back to the oil pan through oil return holes in the cylinder head and crankcase.

Oil filterThe oil filter housing is fitted to the left side of the crankcase. It contains an oil filter insert, made of paper. The oil filter insert is clipped into the oil filtercover and is replaced from the top. When the filter cover is unscrewed, engine oil in the filter housing flows through the drain valve back into the oilpan.

Drain valveThe drain valve is located in the oil filter housing under the filter insert, and opens when the filter cover isunscrewed. This ensures a cleaner filter change and less environmental pollution by reducing the amountof residual oil in the old filter.

Filter bypass valveThe filter bypass valve (release pressure 2. 3 - 3. 0 bar) is located in the filter dome. The normal position of the filter bypass valve is closed. If the oilfilter insert is clogged, the pressure increase in the filter housing opens the filter bypass valve. This ensures that the engine is lubricated, although theengine oil passing through the bypass valve is unfiltered.

Filling valveThe filling valve is placed at the bottom of oil filter housing and is closed with a screw plug (M33x2). Through this valve, engine oil can be poured intothe engine assembly, and after repairs to the engine oil system before starting the engine.



Oil spray nozzlesThe oil spray nozzles are located in the crankcase, two per cylinder. Oil is supplied to the oil spray nozzles through the oil duct. The nozzles sprayengine oil continuously under the piston crowns and the camshaft, thus cooling and lubricating them, while at the same time the upper connecting rodbearings are lubricated by engine oil dripping through an opening in the top of the connecting rod.

Oil temperature sensor and oil pressure sensorThe oil temperature and oil pressure sensor is screwed from the front into the housing assembly under the oil/water heat exchanger, and connectedwith the oil filter through an oil return duct.


Notes


Thermostat Location

The installation location of the thermostats isshown on the right illustration.The circles point to the bleed tabs.

The standard thermostat starts to open at 83C.

Coolant must be changed in regularintervals.

See also maintenance bookletand BeVo



from charge air cooler

to charge air cooler

Exhaust

Air


Notes


Series 900 Engine Models

Baureihe 900


904 LA

VH = 4.25 / 4.8 l


906 LA

VH = 6.37 / 7.2 l

Series 900

4-cylinder in line engine 6-cylinder in line engine

OM 904 / 924 LA OM 906 / 926 LA


OM 906 LA



Outstanding power output and torque characteristics over the whole rpm range Dynamic start-off characteristics and pulling power Attractive power/weight ratio Low fuel consumption High-pressure direct injection with unit pump, pump-line-nozzle system, with peak pressures up to 1 800 bar. Electronic engine control (MR) with electronic system fixed to the engine, and extensive engine protection functions Direct injection with centrally positioned injection nozzle. 3-valve technology with 2 intake valves and one exhaust valve Pneumatically or hydraulically controlled constant throttle Useful engine brake rpm well over rated rpm, up to 2700 rpm Meets the emission legislation of Euromot IIIa Turbocharger with charge air cooling Turbocharger with wastegate valve, depending on engine model Rated engine speed 2200 rpm or 2300 rpm Low service requirements long maintenance intervals engine oil and fuel filter located at front for easy maintenance maintenance-free belt drive Can run on FAME / RME (rape methyl ester) or biodiesel, and engine oil changes are halved High reliability and long runtime Low number of parts variants - many parts are the same on both 4 and 6 cylinder engines Rear engine power take-off ex works



KSKGS 1 2 3 4 5 6


Cylinder Head

Shown on engine 926.9

At the rear part of the cylinder head the cap (arrow) has beenreplaced by the coolant flange for the SCR tank heater solenoidvalve. On the side of the cylinder head the caps have beenpartly replaced by threaded sleeves (1). The bracket for theAdBlue metering device is mounted on these threaded sleeves(1). The other holes on the sides of the cylinder head are sealedby screw plugs (2).

The cylinder heads in the 924.9 and 926.9 engines have beenconverted to vermicular graphite cast iron (GGV-40), for greaterstrength in order to withstand the higher ignition pressure.

1 Threaded sleeve2 Screw plugs


Cylinder Head Sealing Surface Assessment

Check flatness of the cylinder head sealing surface via visualinspection.

In the area of the lines, place a straightedge over the coolant bores (W) onthe cylinder head sealing surface. Check flatness within the sealing area(X) of the cylinder head gasket only.

If a gap forms under the straightedge on the cylinder head sealing surface,the cylinder head sealing surface must be face-ground or the cylinder headexchanged.

When face-grinding, the following notes have to be observed:

- Only carry out face-grinding if an impermissible deviation inflatness is measured in the longitudinal direction.

- Material removal on the cylinder head must not fall belowthe permissible overall cylinder head height, "minimum height".

- Only face-grind the cylinder head sealing surface via face grinding.

- The surface quality of the cylinder head sealing surface must bemaintained.


Cylinder Head Gasket

1 Coolant2 Pressure oil3 Push rods / oil return4 Head bolts5 Return oil crankcase ventilation

1

33 3 3 3 3 3 3 3 3 3311

1

11111

1111

2

4

4

44

4

4

4

4

4

4

44

4

4

5






The maximum shank length of 151 mmis not to be exceeded !

L


Notes


Valve Drive

The 900 model series has two intake valves andone exhaust valve per cylinder. It is thereforereferred to as a "3-valve" engine.

The steel camshaft (which has 5 bearings on the4-cylinder and 7 bearings on the 6-cylinderengine) has one intake and one exhaust cam percylinder, plus one cam for driving the unit pump.

All valves are driven by the camshaft, by means ofmushroom tappets and short push rods. A floatingvalve bridge links and actuates both intake valves.

The complete valve actuation system with rockerarm bearing brackets is bolted to the cylinderhead as a preassembled unit.


Valve Adjustment

Inlet

Exhaust















Notes


Pump-Line-Nozzle Injection System (PLD)

Location of the unit pump

The injection process is performed by the newly developed pump-line-nozzle system, controlled by the Telligentelectronic engine managementsystem.

In the MR system, fuel is delivered to the injection nozzle by individualunit pumps over short, relatively rigid high-pressure injection lines, andthrough the pressure pipe connection screwed into the cylinder head.

A unit pump fitted to the crankcase is assigned to each cylinder. Thepump is driven by another timing cam on the camshaft. The camshafttherefore also has the task of driving the unit pumps, besides thetraditional function of driving the intake and exhaust valves.

The operating principle of the unit pump is based on the same principleas the piston pump, as in the in-line injection pumps used till now, butwithout control edges at the pump plunger.

The quantity injected is determined individually per cylinder by solenoidvalves, which control the start and end of injection.


Pressure Pipe Connection And Nozzle Holder Location

The pressure pipe with integral pin-type filter forms theconnection from the high-pressure injection line to the vertical,centrally positioned nozzle holder combination with the injectionnozzle.

The nozzle holder combination is placed inside a protectivesleeve and is attached to the cylinder head by means of aclamping claw. The combustion gas seal consists of a sealingsleeve.

The protective sleeve itself is protected from the coolant by anO-ring, and on the pressure side by the thread and the contactsurface.

1 Injection line, 25 Nm2 Pressure screw, 40 Nm3 O-Ring4 Pressure pipe5 Nozzle holder kombination6 O-Ring7 Screw, 35 Nm8 Clamping claw9 Constant throttle cap

1

2

3

45

5

6

7

9

8


Removing The Nozzle Holder Combination

1

2

3

45

5

6

7

9

8

10

Injector removal

1. Remove fuel line (1).

3. Remove thrust screw (2).

4. Pull off pressure pipe neck (4).

5. Remove screw (7).

6. Take off clamp (8).

7. Screw impact extractor (10) into injector.

8. Remove injector using the impact extractor.

9. If necessary remove sealing sleeve with

extractor (11) from cylinder head.

10. Seal all openings with appropriate covers

after removal.


11


Install The Nozzle Holder Combination

1

2

3

45

5

6

7

9

8

11


1. Insert a new O-ring (3) at nozzle holder combination (5)

2. Press new sealing sleeve (11) with special tool (12)

onto nozzle holder combination (5)

3. Install nozzle holder combination

4. Mount the clamping claw (8), and tighten Screw (7) to 35Nm

6. Place the new O-ring (6) at pressure pipe connection (4)

7. Fit the pressure pipe connection (4) and tighten pressure

screw (2),40 Nm. Moisten the pressure pipe connection

around the taper seal with engine oil.

8. Install the injection line (1)


Injection Pump Removal

Injection pump removal

1. Disconnect wiring (7) from injection pump.2. Remove fuel line (6).3. Unscrew securing screws (5) of injection pump by

approx. 10 mm.

The preloaded compression spring presses theinjection pump out of the crankcase. If not use specialtool (10) and carefully extract pump.

4. Remove injection pump securing screws (5).5. Remove injection pump (1).6. Remove sealing rings (2, 3, 4) from injection pump.7. Seal all openings with appropriate covers after removal.

10


Injection Pump Installation

Injection pump installation

1. Remove all covers from openingsCoat the new o-rings (2, 3, 4) with lubricating grease, andinstall them with special tool (8).Note: The black o-ring must be allways on top!

3. Carefully clear any dirt or paint residues away from thesealing surface of the MR/PLD unit pump and the crankcase.

4. Carefully press the unit pump in by hand.If the unit pump cam is up at the camshaft, turn the engine.

5. Install the bolts (5) and tighten to 60Nm.6. Install injection line (6) and tighten to 25Nm.7. Connect wiring (7) (1,5 Nm).8. If pump has been changed, new pump code must be

programed via the MiniDiag2.

8


Notes


Piston

Pistons and piston rings are among the most highly stressed enginecomponents. Pistons are therefore constructed of high-temperaturealuminum alloy.

The piston top land and stem are graphite-coated to increase running-in and limp-home capability.

There is a cast-in, reinforced ring groove for the first piston ring.The piston pin support is trapezoidal in shape, to increase thepressure-load surfaces on the piston and connecting rod.

Features of the piston rings:Groove 1: Compression ring

Cast-iron keystone ring with plasma spray layer ofchromeceramic, spherical-lapped.

Groove 2: Compression ring with oil-scraper action.Chrome-plated taper-faced ring with internal angleunderneath.

Groove 3: Oil scraper ringRoof bevel ring with chrome-plated, lapped lands andgarter springs.


Piston Cooling

The oil spray nozzles are located in the crankcase.There is one oil spray nozzle per cylinder. The oilspray nozzles spray engine oil continuously underthe piston crowns to cool them down. Oil is suppliedto the oil spray nozzles through the main oil duct.

Note:It is not permitted to adjust the oil spray nozzle.The oil splasher pipe is soldered in, and theadjustment process could cause initial damage.


Connecting Rod

A particular feature of the manufacturing technologyused to produce the forged steel connecting rod isthe 'cracking' process used to separate the rod fromthe bearing cap.

With this process, the connecting rod (produced inone piece up to now) is split at the big connecting rodeye at an exactly pre-determined fracture line.

The separated parts are then bolted together to forma precise, exact-fitting attachment for the bearing.

Note: Because of the 'cracked' surface structure,special care and cleanliness is required whenperforming repairs.


Crankcase

All engines are based on the particularly stable, noise-optimizedcrankcase, which is made of a high-carbon/ cast iron alloy.

Design features:

Both the 4 and the 6-cylinder engine have only one variant.Compact design through integration of the oil cooler, the unitpumps, and the coolant, fuel and oil ports.

Highly rigid, high carbon /cast iron alloy. Rigid sidewalls,extending well past the center of thecrankshaft. This means thatthe separating surface of the oil pan is located lower than thelevel of the crankshaft center.

The front engine mount is located at cylinder 2.Induction-hardened cylinder contact surfaces.

On the left on the flywheel side, an assembling lug is providedfor attaching the compressor with power steering pump.


Induction-Hardened Cylinder Contact Surfaces

Cylinder contact surfaces with induction-hardened stripsare provided at the upper piston return point, around therings, to increase engine life.


Notes


Fuel System


Fuel System

Fuel circuit schematic diagram1 Fuel feed pump (KFP)1.1 Pressure limiting valve in KFP pump (9.2 bar)1.2 Check valve in KFP pump (0.2 bar)2 Fuel filter (KF)2.1 Fuel drain valve2.2 Constant vent in fuel filter (KF)3.1 Bypass from fuel feed duct to fuel return duct5 Nozzle holder combination8 Overflow valve (4.5 bar)8.1 Constant vent (0.5 mm)10 PL

Documents

Training Doc Mercedes 900