Timing chain BMW 745i 2004 E65 N62B44 Engine Workshop Manual

Downloaded from www.Manualslib.com manuals search engine Cylinder Heads
The two N62 cylinder heads are a new development from BMW. They are fitted with the
Valvetronic system. The secondary air ducts for subsequent exhaust gas treatment are
integrated in the cylinder heads. The cylinder heads are cooled by the “cross-flow” princi-
ple.
The inlet camshaft and the Valvetronic eccentric shaft are jointly guided by a bridge sup-
port. The cylinder heads are made from aluminum and are manufactured using gravity die-
casting. The upper timing chain housing is now an integral part of the cylinder head.
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N62 Engine
Cylinder Head
1. Cylinder Head for Cylinder Bank 1-4 7. Mounting VANOS Intake Solenoid
2. Cylinder Head for Cylinder Bank 5-8 8. Mounting VANOS Outlet Solenoid
3. Upper Timing Chain Guide with Oil Jet 9. Oil Pressure Switch
4. Mounting for VANOS Intake Solenoid 10. Chain Tensioner Mount
5. Mounting for VANOS Outlet Solenoid 11. Upper Timing Chain Guide with Oil Jet
6. Chain Tensioner Mount43-02-20

Downloaded from www.Manualslib.com manuals search engine Cylinder Head Gaskets
The cylinder head gasket is a multi-layer steel
gasket with a rubber coating. This type of gas-
ket has previously been used on other engines.
The B44 head gasket has a 6 mm hole in a flap
on the outlet side of the cylinder head gasket.
The cylinder head bolts for the N62 engine are
M10x160 necked-down “stretch” bolts.
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The lower part of the timing chain housing is
bolted to the cylinder head using two M8x45
bolts.
Camshafts
The camshafts are made from chilled cast iron
and are hollowed to reduce weight. The cam-
shafts are weighted with counterbalances for
equalizing imbalances in the valve gear.
1. Camshaft sensor wheels (sintered metal)
2. Thrust bearing area with oil ducts for the
VANOS units
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N62 Engine
42-02-23
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N62 Engine
VANOS Sectional Views
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The figures above show a sectional view of one VANOS unit. The VANOS unit is secured
by a central bolt through the hub (7) to the camshaft. The timing chain connects the crank-
shaft with the housing of the unit.
There is a recess in the hub in which the locking pin (6) engages without oil pressure
(sprung). When the solenoid valve is activated to supply oil pressure to the VANOS unit,
the locking pin is compressed and releases the VANOS for adjustment.
The internal blades (9) are spring loaded (10) to provide a seal between the oil pressure
chambers (11 and 12). The torsion spring (3) acts against the camshaft torque.
42-02-4942-02-45
VANO’S Components
1. Housing with Sprocket 7. Hub
2. Front Plate 8. Black Plate
3. Torsion Plate 9. Blade
4. Lock Spring 10. Spring
5. Retaining Plate for Lock Spring 11. Pressure Chamber A
6. Spring Loaded Locking Pin 12. Pressure Chamber B

Downloaded from www.Manualslib.com manuals search engine 35
N62 Engine
Chain Drive
The camshafts are driven by a toothed chain, one for each cylinder bank. The oil pump is
driven by a separate roller chain.
1. Sensor wheels for the camshaft position sensor, cylinder bank 1-4
2. Tensioner Rail, Cylinder 5-8
3. Chain Tensioner, Cylinder Bank 5-8
4. Sensor Wheel for the camshaft position sensor, cylinder bank 5-8
5. Upper timing chain guide with integrated oil jet
6. Guide rail
7. Sprocket for Oil Pump Drive
8. Timing case lower section
9. Tensioning rail, cylinder bank 1-4
10. Solenoid Valve, VANOS exhaust camshaft
11. Solenoid Valve, VANOS intake camshaft
12. Upper Timing Chain Cover
13. Chain Tensioner, Cylinder Bank 1-4
14. VANOS exhaust camshaft Bank 1-4
15. Upper Timing Chain guide with integrated oil jet
16. VANOS intake camshaft 1-4Chain Drive
43-02-50

Downloaded from www.Manualslib.com manuals search engine 41
N62 Engine
Leakage Restraint System in the Water Pump
The water pump has a leakage restraint system for the functional leakage from the pump
shaft piston ring type seal. The coolant which escapes through the pump shaft sliding ring
seal usually accumulates and evaporates through a hold in the leakage chamber (evapora-
tion area).
If the sliding ring seal is faulty, the leakage chamber fills
completely with coolant. Sliding ring seal leakages can
be detected by monitoring the fluid level in the leakage
chamber (inspection hole).
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In the past, fully functional water pumps were often replaced because the functional
sliding ring seal leakage which is necessary for water pump operation resulted in evapora-
tion residues being left on the external walls of the water pump.
The leakage restraint system has the advantage in that the coolant escaping from the slid-
ing ring seal (normal, functional leakage) evaporates without a trace and cannot be mis-
takenly identified as a water pump defect during visual inspections.
Timing Chain Cover Lower Section
The waterpump mounts to the lower section to
channel coolant to the engine block.
42-02-61 Water Pump
1. Impeller
2. Sliding Ring Seal
3. Leakage Chamber / Evaporation Space
4. Leakage Chamber Cover
5. Delivery from the sliding ring seal to the leakage chamber
6. Hub of pulley and viscous clutch
Timing Chain Cover Lower Section
1. Coolant to Engine
2. Rear Water Pump Housing in Lower Section
3. Mount for Drive Belt Tensioner Pulley
4. Crankshaft Radial Seal
42-02-62