Page 261 of 1002
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-
Camshaft Timing Chain -. -
Measure gap (B) between secondary timing chain tensioner
and intake camshaft sensor wheel. Make note of distance.
To determine VANOS control travel:
Distance
I3 - distance A = a minimum of 8.5 mm
CAUTION-
If the adjustment travel is less than 8.5 mm the VANOS ad-
justment unit must be removed and readjusted. See
VANOS
control unit, removing (M52 engine)
and VANOS con-
trol unit, installing
(M52 engine).
Remove special tools:
Cranltshaft locking tool.
Camshaft
loclting tool set.
Air fitting.
* VANOS cable adaptor.
- Install VANOS oil line with new seal
- Install oil baffle cover above intake camshaft.
- Install cylinder head cover mounting studs to rear of head.
- Install cylinder head cover,
Tightening
torques
Cylinder head cover 10 Nrn (89 in-lb)
VANOS oil line
32 Nm (24 R-lb)
VANOS solenoid to control unit 30 Nrn (22 ft-lb)
- Installation of remaining parts is reverse of removal.
Page 270 of 1002
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1 17-34
1 Camshaft Timing Chain
DOUBLE VAMOS SYSTEM
(M52 TU AND M54 ENGINES)
Double VANOS system function
The M52TU and M54 6-cylinder engines are equipped with a
Double VANOS system that varies intake and exhaust cam-
shaft timing.
The main components of the Double VANOS system are:
lntalte and exhaust camshafts with helical spline inserts.
Camshaft sprockets with adjustable gears.
VANOS actuators (two position piston housing with
inter-
nallexternal helical spline cup).
Three-way solenoid switching valves.
Camshaft position impulse wheels.
Hall effect camshaft position sensors.
Camshaft position
IS varied based on engine rpm, throttle po-
sition signal, intake air and coolant temperature.
Page 275 of 1002
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11 7-39
Camshaft Timing Chain
4 Cover oil hole in VANOS control unit (arrow) with shop towel
to capture oil which will spray when compressed air line is
connected.
- Connect compressed air line to air fitting. Apply air pressure
set to
2 - 8 bar (30 - 110 psi).
4 With compressed air line connected, turn engine clocltwise
using crankshaft center bolt at least two rotations, until cylin-
der
1 is at (TDC) position (intake and exhaust carnshafl lobes
as shown arrows).
Do not rotate engine
countercloclwise to reach the top dead
centerposition. Instead, complete another two complete
Remove sealing plug from bore under starter. Lock
crank-
shafl in TDC position with BMW special tool 11 2 300
(arrow).
-
4 Unscrew and remove threaded studs (arrows) at rear of
cylinder head.
Page 276 of 1002
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. .. ~-
Camshaft Timing Chain -
4 Secure camshafts in TDC position using BMW special tool
set
11 3 240.
- Disconnect compressed air line, leaving compressed air fit-
ting attached to VANOS control unit.
NOTE -
Oil will drain from pressure line. Have a container and rags
ready
4 Unscrew sealing plugs from VANOS control unit (arrows).
NOTE-
Oil will drain from sealing plug bores. Have a container and
rags ready
4 Pull sealing caps straight out of VANOS control unit with
BMW special tool 11 6 170, or with short nose pliers.
NOTE-
Additional oil may drain from VANOS control unit.
4 Remove set screws (left-hand thread) on ends of intake and
exhaust camshafts.
NOTE-
Set screws have left hand threads. Remove with a clockwise
motion.
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I Camshaft Timing Chain
- Using new gasket, install VANOS control unit to cylinde~
head.
Reinstall engine support eye.
Tightening torques VANOS control unit to cylinder head
M6 nut 10 Nm (89 in-lb)
M7 nut 14 Nm (10 ft-ib)
4 Insert and tighten VANOS hydraulic piston set screws on
intake and exhaust camshafts.
CAUTIOI\C
Set screws have left hand thread Tighten counterclocltwise.
Tightening torque
Hydraulic piston
to splined shaft 10 Nm (89 in-lb)
(set screw)
4 Replace sealing caps inside VANOS control unit with BMW
special tool 11 6 170, or short flat nosed pliers.
Insert and secure VANOS sealing plugs (arrows), using new
sealing O-rings.
Tightening torque Sealing plug to VANOS control unit 50 Nm (37
it-lb)
Remove compressed air fitting from VANOS control unit
Fit VANOS oil line banjo bolt with new seals. Attach oil line to
VANOS control unit.
Tightening torque Oil line to VANOS control unit (banjo bolt) 32
Nm (24
it-lb) -
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Camshaft Timing chain1
< With compressed air line connected, turn engine at least
twice in direction of rotation until cylinder
1 intake and ex-
haust camshaft lobes (arrows) face each other.
Do not rotate engine counterclockwise to reach the top dead
center position. Instead, complete another two complete ro-
Remove sealing plug from bore at bellhousing. Secure crank-
shaft in
TDC position with BMW special tool 11 2 300 (ar-
row).
- Remove cylinder head cover studs at rear of cylinder head.
< Place BMW special tool 11 3 240 over camshafts ends and
measure clearance of tool to cylinder head surface.
NOTE-
If the exhaust side of the tool (A) is not flush with the head,
adjust camshaft timing as described below.
Due to flexible sprocket design and VANOS control unit tol-
erances and play, the
intake side of special tool 11 3 240
(B) may be up to 1 mm (0.04 in) above the surface of the
cylinder head. This is normal. Reassemble engine. Other-
wise, adjust camshaft timing as described below.
- Remove double VANOS control unit. See VANOS control
unit, removing
(M52 TU and M54 engines).
< Press down on secondary chain tensionerand lock into place
using BMW special tool
11 3 292 or equivalent pin or drift.
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-- - -- - -- Camshaft Timing chain1
- Remove camshaft locking tools from rear of camshafts
- Remove BMW special tool 11 4 220 (adjustable primary
chain tensioner). Reinstall primary chain tensioner.
Tightening torque Primary chain tensioner to cylinder head
70
Nm (52 it-lb)
- Remove crankshaft locking tool from transmission bellhous-
ing. Reinstall sealing plug.
- Remove VANOS setup bracket from front of cylinder head
- lnstall VANOS control unit as described earlier in this group.
- Remove compressed air fitting (BMW special tool 11 3 450)
from VANOS control unit.
- Fit VANOS oil line banjo bolt with new seals. Attach oil line to
VANOS control unit.
Tightening torque
Oil line to VANOS control unit (banjo bolt) 32 Nm (24 H-lb)
- Remainder of installation is reverse of removal, noting the fol-
lowing:
lnstall spark plugs.
* lnstall intake camshaft plastic baffle prior to installing cylin-
der head cover. lnstall ignition coil packs and connect elec-
trical harness connectors.
Install radiator cooling fan.
- lnstall air filter housing and top engine cover.
Tightening torque Radiator cooling fan
(VISCOUS clutch) to 40 Nm (30 ft-lb)
coolant pump
Cyitnder head cover to cylinder head 10 Nm (89 in-lb)
Sparlc plug to cylinder head 25 Nm (18 ft-lb)
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... -.
Camshaft Timing chain1
Timing chains, removing
(M52 TU and M54 engines)
Camshaft timing chain removal requires that the oil pan be re-
moved. See
119 Lubrication System. Also required is re-
moval of the VANOS control
unit and disassembly of the
intake and exhaust camshaft sprocket assemblies as de-
scribed earlier in this repair group.
Special BMW
service tools are needed for timing chain re-
moval and installation. The special tools assure proper timing
of the valvetrain. Precise
marlts to set the timing on the cam:
shafts are not provided for reassembly. Read the procedures
through before beginning the job.
CA
UTION-
If the camshafts are not properly timed, the pistons can con-
tact the valves.
- D~sconnect negative (-) cable from battery.
CAUTION-
* Disconnecting the battery may erase fault code@) stored in
control module memory. Check for fault codes using spe-
cial
BMW diagnostic equipment.
Prior to disconnecting the battery, read the battery dis-
connection
cautfons given in 001 General Cautions
and
Warninqs.
- Remove VANOS control unit. See VANOS control unit, re-
moving
(M52 TU and M54 engines).
Remove sealing plug from crankcase below starter and se-
cure crankshaft with
BMW special tool ll 2 300.
Drain engine cooling system. See 170 Radiator and Cool-
ing System.
Remove belt driven cooling fan, fan shroud, and thermostat
housing. See
170 Radiator and Cooling System.
Remove drive belts. See
020 Maintenance.
NOTE-
Mark direction of belt rotation if reusing belt.
- Remove water pump pulley fasteners and pulley.
- Drain engine oil and remove oil pan as described in 119
Lubrication System.