BMW N73B60 Instructions de fonctionnement
Subject Page
N73B60 Engine
Objectives of the Module........................................................................2
Purpose of the System............................................................................3
Technical Data........................................................................................ 4
Disassembly - Components
Intake Manifold....................................................................................... 6
Cylinder Head Cover...............................................................................8
Ancillary Components and Drive Belts.................................................... 9
Cylinder Heads......................................................................................10
Valvetronic.............................................................................................11
Fuel Injectors.........................................................................................14
Lubrication Components.......................................................................15
Crankshaft and Bearings.......................................................................17
Pistons and Connecting Rods...............................................................17
Crankcase.............................................................................................19
Lubrication System................................................................................19
Cooling System.....................................................................................21
Table of Contents
N73B60 Engine - Workbook
2
N73B60 Engine - Diagnosis
N73B60 Engine
Model: E66 - 760Li
Production: MY 2003
This intent of this workbook is to assist you with key components for disassembly/reassem-
bly in addition to the detailed information found in the Repair Instructions, Technical Data
and Tightening Torques from the latest TIS information.
This section will be instructor led for a brief review of the N73 engine. You are encouraged
to use this workbook with the latest TIS information to make notes during disassembly/
reassembly of the engine. This will be valuable to you as supplementary information or a
memory refresher when performing repairs in the future.
NNoottee::For more in depth and detailed information about the N73 engine, refer to the ST047
2003 Systems Diagnosis training manual.
For additional and updated information, always refer to:
www.bmwcenternet.com
- TIS information/updates
- Service Information Bulletins
- DCS messages
Objectives:
After completion of this module you will be able to:
• Disassemble the N73 engine.
• Perform critical measurements and observations to determine engine condition.
• Correctly reassemble (including valve gear timing) the N73 engine.
3
N73B60 Engine - Diagnosis
N73B60 Engine
Purpose of the System
The N73 engine is a complete new BMW development from the NG Series (New
Generation) as a B60 (6 liter). The N73B60 will be used in the E66 as a 760Li (USA).
The BMW 760Li will set new standards in terms of performance and driving dynamics in
the 12-cylinder market segment as well as significantly reduce fuel consumption.
For the first time at BMW, Valvetronic technology (combination of Bi-VANOS and variable
intake valve lift) is supplemented by direct injection (DI).
In addition, the N73 cylinder heads use 4 valve technology.
The combination of these cutting edge technologies provides low fuel consumption and
maximum power output and torque, making the N73 the best engine in its class.
KT-9765
4
N73B60 Engine - Diagnosis
Technical Data
Technical Data Comparison N73B60 M73B54
V-angle configuration 12 cyl. V / 60º 12 cyl. V / 60º
Displacement (cm 3) 5972 5379
Bore / Stroke (mm) 89 / 80 79 / 85
Cylinder spacing (mm) 98 91
Crankshaft main bearing diam. (mm) 70 75
Conrod big end diam. (mm) 54 48
Power output (kW/HP)
at engine speed (rpm)
320 / 438
6000
240 / 326
5000
Torque (Nm)
at engine speed (rpm)
600
3950
490
3900
Idle speed (rpm)
Maximum engine speed (rpm)
550
6500
600
6500
Compression ratio 11.3 : 1 10 : 1
Valves per cylinder 4 2
Intake valve diam. (mm) 35 42
Exhaust valve diam. (mm) 29 36
Intake valve lift (mm) 0.3 - 9.85 10.3
Exhaust valve lift (mm) 9.7 10.3
Engine weight (kg) 280 -
Fuel requirement Premium unleaded Premium unleaded
Knock control Yes Ye s
Injection pressure (bar) 50 - 120 3.5
Digital Motor Electronics (ECM) 2x MED 9.2.1 & Valvetronic ECU
with 2x HDEV ECU
2x ME 5.2 & EML IIIs
Emission compliance level LEV LEV
Firing order 1-7-5-11-3-9-6-12-2-8-4-10 1-7-5-11-3-9-6-12-2-8-4-10
Fuel consumption savings compared
with M73
12 % -
Maxmimum regulated vehicle speed
(km/h / mph)
250 / 155 250 / 155
5
N73B60 Engine - Diagnosis
Power and Torque Output - N73B60 / M73B54
N73B60
M73B54
Engine RPM
6
N73B60 Engine - Diagnosis
Intake Manifold
The intake system is a complete component constructed of magnesium in a shell type
design and has separate manifold chambers for each cylinder bank.
1. Intake manifold pressure sensors
2. Captured gaskets
3. Pressure control valves for crankcase
ventilation
4. Throttle valves
The individual parts of the intake system are bonded and bolted to each other, providing
considerable weight reduction (separating the shell halves is not permitted).
The entire intake system is protected against corrosion by a dip coating procedure. The
fastening bolts of the add on parts are also coated and must be replaced in the event of
damage, to prevent corrosion and pitting.
All of the gaskets (2) are secured by retainers (captured) to provide ease of installation. The
intake system is isolated from the engine by rubber elements on the fastening bolts.
An intake manifold pressure sensor (1) is used for each cylinder bank. Recording the man-
ifold differential pressure is necessary for the correct throttle position (synchronization) so
that a manifold differential pressure of 50 mbar can be balanced on each bank.
Both sides of the induction system are fitted with a pressure control valve (3) for crankcase
ventilation which is distributed to both banks.
NNoottee::When replacing the spark plugs, it is necessary to remove the entire intake system to
avoid damaging the spark plugs during installation. The spark plugs must be replaced
every 100,000 miles in US vehicles.
KT-9589
7
N73B60 Engine - Diagnosis
Intake Manifold - Removal
Top Diagram
• Remove plug connections on the throttle
assemblies (1).
• Detach engine vent hoses from pressure con-
trol valves (2).
• Detach oustide braces for intake manifold
(3 L/R).
Lower Diagram
• Remove plug connections on the intake mani-
fold pressure sensors (1 L/R).
• Remove bolts (2) along sections (3).
• Lift intake manifold up to remove.
Questions
HHoowwmmaannyyaattttaacchhiinnggbboollttssaarreetthheerree??
WWhhaattiisstthheettiigghhtteenniinnggttoorrqquuee??NNmm
HHoowwaarreetthheeiinnttaakkeemmaanniiffoollddggaasskkeettsshheellddiinnppllaaccee??
CCaanntthheeggaasskkeettssbbeerreeuusseedd??
NNootteess::
001
8
N73B60 Engine - Diagnosis
Cylinder Head Cover (right) - Removal
CCaauuttiioonn::DDoonnoottbbeennddaannyyhhiigghhpprreessssuurreelliinneess!!
Top Diagram
• Detach high pressure lines (1) at mounting
points (2).
OOnnhhiigghhpprreessssuurreeppuummpp::
• Detach feed line (3).
• Detach high pressure line (4).
• Detach leakage line (5).
• Detach high pressure lines from fuel rail (6).
Lower Diagram
• Remove Valvetronic motor.
• Remove mounting bolts (1) and high pressure
pump (2).
• Remove bolts (3) and pull out spacer (4).
• Remove Non-Return Valves and cylinder head
cover perimeter bolts.
Questions
WWhhaattiisstthheettiigghhtteenniinnggttoorrqquueeffoorrtthheeccoouupplliinnggnnuuttssoonnffuueelllliinneess33--66??NNmm
WWhhaattsshhoouullddyyoouuddoottootthheessppaarrkkpplluuggddoommeess((sslleeeevveess))bbeeffoorreerreeiinnssttaalllliinnggtthheemm??
AAfftteerrrreemmoovviinnggtthheehhiigghhpprreessssuurreeppuummpp((22)),,wwhhaattootthheerr
ccoommppoonneennttmmuussttbbeerreemmoovveeddffrroommtthheeppuummppmmoouunntt--
iinnggbbaassee??
WWhhyysshhoouullddccaauuttiioonnbbeettaakkeennttoonnoottbbeennddaannyyoofftthhee
hhiigghhpprreessssuurreeffuueelllliinneess??
002
DSC00579
9
N73B60 Engine - Diagnosis
Ancillary Components and Drive Belts - Removal
Remove the following compo-
nents:
1. Water pump pulley
2. 6 rib main drive belt
3. Main drive belt tensioner
4. Alternator
5. Deflection pulley
6. Power steering and dynamic drive pump
7. A/C compressor drive belt tensioner
8. Crankshaft pulley
9. A/C compressor
10. 4 rib A/C compressor drive belt
TToorreemmoovveetthheeddrriivveebbeellttss::
The tensioning pulley is pushed back using a
Torx tool in the recess provided (1) and fixed in
this position by inserting a locking pin as shown
(2).
The cooling module of the N73 includes an
external engine oil cooler. The engine oil cooler
is located in front of the engine coolant radiator
above the A/C condenser.
The engine oil flows from the oil pump through a
channel in the crankcase to a connection on the
alternator support. The alternator support has
an oil thermostat (arrow to the right).
A wax element in the oil thermostat opens the
supply flow to the engine oil cooler from an oil
temperature of 100 ºC to 130 ºC.
A partial amount of engine oil will permanently
bypass the oil thermostat, even when it is fully
open and flows uncooled through the engine.
The engine oil cooler helps to keep the engine oil
temperature below 150 ºC.
KT-9644
42-02-16
DSC00629
10
N73B60 Engine - Diagnosis
Cylinder Heads
The two N73 cylinder heads are a new development from BMW and have been adapted to
the new direct injection system. The cylinder heads are equipped with Valvetronic valve
gear and Bi-VANOS. The inlet camshaft and the Valvetronic eccentric shaft are jointly guid-
ed by a bridge support.
The ports for the high pressure fuel injectors are located on the intake side. The engine is
equipped with a high pressure fuel pump for each cylinder head. Each cylinder head has
a bucket-tappet drive on the exhaust camshaft for the high pressure fuel pump.
The secondary air ducts for subsequent exhaust gas treatment are integrated in the cylin-
der heads. The cylinder heads are cooled by the “cross-flow” principle. The cylinder heads
are made from aluminum and are manufactured using gravity die-casting.
Cylinder Head Gaskets
The cylinder head gasket is a triple layer steel gasket with rubber coating. This gasket ver-
sion is already established in previous engines (N62).
The cylinder head bolts for the N73 engine are M10x160 necked-down “stretch” bolts.
NNoottee::TThheesseebboollttsssshhoouullddaallwwaayyssbbeerreeppllaacceeddwwhheennrreeppaaiirrssaarreeppeerrffoorrmmeedd..
The lower part of the timing chain housing is bolted to the cylinder head using two M8x45
bolts (arrows above).
DCS00654
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