1999 BMW 528i exhaust

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Camshaft Timing chain1
VANOS control unit, installing (M52 engine)
CAUTION-
Incorrect installation of the VANOS control unit may result in
damage to the engine.
- Make sure camshafts and crankshaft are loclted in TDC po-
sition with BMW special tools as described during VANOS
removal.
< Rotate exhaust camshaft sprocket clocltwise (as viewed from
front of engine) using BMW special tool
11 5 490, until detent
position stop is reached.
4 Apply a small amount of liquid gasket sealer (Three Bond
1209
8 or equivalent) to VANOS housing alignment dowels
on front of cylinder head. Install a new
gasket.
< Push VANOS piston gear cup (arrow) into VANOS housing
until it bottoms out. Position VANOS control unit in front of
camshafts, but do not engage splines on gear cup.

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11 7-20
Camshaft Timing Chain
4 lnstall BMW special tool 1 I 5 490 on exhaust camshaft.
- Insert the helical-toothed splined shafl (arrow) into the heli-
cal-toothed sprocket while rotating gears and chain counter-
clockwise with special tool.
CAUTION- Ensure
that the first available tooth engages. It is important
that the exhaust camshaft sprocket be turned only the mini-
mum amount necessary to engage the gear cup. If this pro-
cedure is done
incorrectlq: the VANOS system may not fully
function.
- Install and tighten down VANOS control unit fasteners
Tightening torques
VANOS control unit to cylinder head
M6 nuts 10 Nm (89 in-lb)
M8 bolts 22 Nrn (17 ft-lbj
- Press down on secondary timing chain tensioner and remove
lock tool.
Remove primary timing chain tensioner
(arrow)
CAUTION-
Timing chain tensioner is under spring tension.
lnstall adjustable primary chain tensioner
(BMW special tool
11 4 220) and preload timing chain by tightening to 1.3 Nm
(I I in-lb).

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Camshaft Timing Chain/ - - - - - - . - - . - .
Tighten exhaust camshaft sprocket mounting bolts (arrows)
alternately in two stages.
Tightening torques
Secondary timing chain sprocltets to camshafts
Stage
1
Stage 2
5 Nm (44 in-lb)
22 Nm (17 ft-lb)
- Remove crankshaft locking tool and camshaft locking tool
set.
- install camshaft gear bolt access plugs using new sealing
washers and tighten.
- Remove timing chain tensioning tool from side of cylinder
head. Install primary chain tensioner with new sealing wash-
er and tighten.
Tightening torques
Access plugs to VANOS control unit 50 Nm (37 ft-lb)
Primary timing chain tensioner
plug to 70 Nm (52 ft-lb)
tensioner sleeve
- Check adjustment VANOS system, see VANOS timing,
checking and adjusting
(M52 engine).

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4 With crankshaft at TDC position, remove vibration damper
bolts (arrows) and remove vibration damper.
< Mount crankshaft holding tool (BMW special tool 11 2 150
and
11 2 410) to crankshaft hub. Counter hold crankshaft and
loosen crankshaft hub retaining bolt.
Crankshaft hub retaining bolt is torqued to
410 Nm (300 ft-lb).
Do not use flywheel
locliing tool to hold cranl(shait stationary
to loosen or tighten crankshaft hub center bolt. Use only the
special tools specified, or equivalent hub holding tool.
- Remove crankshaft hub.
- Remove cylinder cover mounting fasteners and remove cyl-
inder head cover.
NOTE-
The cylinder head cover mounting bolt insulators and gas-
lets should be reinstalled in their original positions. Make
note of their arrangement during removal.
- Drain engine oil, remove oil pan. See 119 Lubrication Sys-
tem.
Remove primary timing chain tensioner (arrow).
CAUTION-
Timing chain tensioner is under spring tension. I
- Remove VANOS control unit. See VANOS control unit, re-
moving
(M52 engine).
- Remove fasteners from intake and exhaust camshaft
sprocket.

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[camshaft Timing Chain
< While pressing down on secondary timing chain tensioner
install locking tool (BMW
11 3 292) or a similar pin.
NOTE-
Two types of secondary timing chain tensioners are used,
with either two holes (shown) or a single hole for the
locking
pin tool.
- Remove intake and exhaust sprockets together with
secondary chain.
< Remove secondary timing chain tensioner bolts (arrows)
and remove tensioner.
- Remove primary timing chain sprocket from exhaust
camshaft.
- Remove sprocket and hang timing chain from end of exhaust
camshaft.
4 Remove secondary chain guide bolts (arrows) and remove
guide.

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1 17-30
I Camshaft Timing Chain
Timing chain, installing
(M52 engine)
CAUTION-
The procedure outlined below assumes that the camshafts
and the crankshaft are
lockedin the TDCposition with BMW
special tools.
- Inspect timing chain and sprocltets and guide rails for wear.
Replace worn parts.
NOTE-
If any of the sprockets are being replaced due to wear, the
chain should also be replaced.
Install primary timing chain
on exhaust camshaft. to crankshait
sprocket and hang
4 Apply a small bead oi silicon sealer (Three Bond 1209 @or
equivalent) to corners where tim~ng cover meets cylinder
head
(arrows).

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-- -
Chain 1
- Install cylinder identification trigger plate to front of intake
camshaft.
- Install spacer to front of intake camshaft
- Install secondary chain sprockets and chain as an assembly
so that arrows on sprockets are pointing up. Center mounting
holes in sprockets to bolt holes in camshafts.
4 lnstall thrust washers and spring plate to intake cam
sprocket.
Tighten intake camshaft sprocket nuts.
- Install VANOS control unit, see VANOS control unit, install-
ing
(M52 engine).
Tightening torque
Intake camshaft sprocket nuts to studs
(ME) 1011 Nm (8919 In-lb) 502117068
- Unlock and release secondary chain tensioner,
4 Preload primary timing chain by torquing adjustable primary
chain tensioner (BMW special tool
11 4 220) to 1.3 Nm
(11 in-lb).
- Tighten exhaust camshaft sprocket bolts in two stage
Tightening torque Exhaust camshaft sprocket bolls (M7)
Stage 1
5 Nrn (44 in-lb)
Stage
2 22 Nm (17 ft-lb)
- Remove crankshaft locking tool and camshaft locking tools.
< Align hub with keyway and tap into place. Insert new center
bolt with washer shoulder (arrow) facing hub.
CAUTION-
Inspect woodruff ley for damage before installing hub.
- Attach crankshaft holding tool (BMW special tools 11 2
15011 1 2 410) to hub. Counterhold hub with tool while tight-
ening center bolt.
CAUTION-
Do not use flywheel locling tool to hold crankshaft stationary
to loosen or tighten
cranlshaft hub center bolt. Use only the
special tools specified, or equivalent hub holding tool.

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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.