116-
1
0
CYLINDER
HEADAND
VALVETRAIN
NOTE-
When
checking
a
cam
follower,
make
sure
the
corre-
sponding
camshaft
lobe
ís
facing
up
so
that
there
is
no
valve
spring
pressure
on
the
follower
.
4
.
To
replace
a
cam
follower,
remove
appropriate
cam-
shaft
.
Refer
to
camshaft
removal
procedures
given
ear-
lier
.
5
.
Once
camshaft
is
out
of
way,
withdraw
faulty
cam
fol-
lower
and
replace
with
new
one
.
Inspect
cam
follower
bores
for
wear
and
scoring
.
6
.
Camshaft,
timing
chain
and
cylinder
head
cover
reas-
sembly
is
reverse
of
disassembly
.
Tightening
Torques
"
Camshaft
bearing
caps
to
cylinder
head
M7
....
.
..
.
......
.
.....
...
.
..
.
15
Nm
(11
ft-Ib)
"
Cylinder
head
cover
to
cylinder
headltiming
chain
cover
M6
....
.
..
.
.
.
..........
...
.
.
..
10
Nm
(89
in-lb)
"
Timing
chain
hydraulic
tensioner
to
cylinder
head-see
117
Camshaft
Timing
Chain
"
Timing
chain
sprocket
to
camshaft
flange
(M6)-see
117
Camshaft
Timing
Chain
CYLINDER
HEAD
AND
VALVETRAIN,
RECONDITIONING
Table
c
.
Valve
Guide
Specifications
Fig
.
16
.
Valveguide
wear
being
checked
with
dial
indicator
.
Insert
new
valve
until
stem
end
is
flush
with
end
of
guide(white
arrow)
.
See
Table
c
for
wear
limits
.
NOTE-
Valve
guides
"
Intemational
Organization
for
Standardization
(ASO)
tolerance
classes
are
Gsted
in
Table
c
.
ISO
allowanc
BMW
does
notsupply
valve
guides
as
replacement
parts
.
If
esare
based
on
nominal
sizes
and
should
beused
to
a
valve
guide
is
excessively
worn,
it
should
be
reamed
to
ac-
determine
proper
fit
.
Most
machine
shops
should
cept
oversized
valve
stems
.
Valve
guide
specifications
are
have
thís
informationavailable
listed
in
Table
c
.
"
Replacement
valve
guides
may
be
available
through
aftermarket
suppliers
.
Valve
guide
replacement
re-
Valve
guides
should
be
checked
for
wear
using
a
new
quires
specíal
tools
and
a
press
.
It
is
also
necessary
valve
.
See
Fig
.
16
.
Be
sure
to
thoroughly
inspect
the
cylinder
to
heat
the
cylinder
head
and
chile
the
valve
guides
head
to
ensure
that
it
can
be
reused
before
reworking
the
when
replacing
the
guides
.
guides
.
"
BMW
suppllesoversize
valves
.
Sea
Valves
for
addi-
tional
information
.
Specifications
M42
engine
M421M44
engines
M50
engine
M50,M52,
S50
US,
S52
~
(1992)
~
(1993-1998)
~
(1992)
~
US
engines
(1993-1998)
Valve
guide
wear,
maximum
(valve
tílt
clearance
measured
with
new
valve)
0
.5
mm
(0
.020
in)
0
.5
mm
(0
.020
in)
0
.5
mm
(0
.020
in)
0
.5
mm
(0
.020
in)
Valveguide
inside
diameter,
installed
(tolerance
per
ISO
allowance
H7)
Standard
7
.0
mm
(0
.276
in)
6
.0
mm
(0
.236
in)
7
.0
mm
(0.276
in)
6
.0
mm
(0
.236
in)
Oversize
1
7
.1
mm
(0
.279
in)
6
.1
mm
(0
.240
in)
7
.1
mm
(0.279
in)
6
.1
mm
(0
.240
in)
Oversize
2
7
.2
mm
(0
.283
in)
6
.2
mm
(0
.244
in)
7
.2
mm
(0
.283
in)
6
.2
mm
(0
.244
in)
116-12
CYLINDER
HEADAND
VALVETRAIN
Valve
Seats
Valve
Springs
The
valve
seats
should
be
resurfaced
whenever
new
valves
The
valvesprings
should
be
checked
for
fatigue
.
To
quickly
or
valve
guides
are
installed
.
Cutters
are
required
to
resurface
check
the
springs,
line
them
up
in
a
row
.
Place
a
straight
edge
the
seats
.
Always
check
thevalves
for
leaks
after
recondition-
across
thetop
of
the
springs
.
Any
spring
that
is
significantly
ing
a
valve
seat
as
described
above
.
Table
e
lists
valve
seat
shorter
than
theothers
is
worn
and
should
be
replaced
.
dimensions
.
NOTE-
NOTE-
Valve
spring
specifications
and
wear
límits
arenot
Standard
size
replacement
valve
seats
are
not
avail-
available
from
BMW
.
ablefrom
BMW
.
Replacement
valve
seats
are
only
available
from
BMW
in
0
.4
mm
oversize
(oversized
in
both
height
and
diameter)
.
The
manufacturer
does
not
provide
specífications
for
valve
seat
replacement
for
the
enginescovered
by
this
manual
.
Table
e
.
Valve
Seat
Dimensions
"Y
Valve
seat
outside
dia
.
(B)
CYLINDER
HEAD
AND
VALVETRAIN,
RECONDITIONING
60
°
yl
1
B11110c
Specification
M42
engine
M42
engine
M44
engine
M50
engine
M501M52
engines
S50USIS52US
(1992)
(
(1993-1995)
I
(1996-1998)
(1992)
I
(1993-1998)
I
engines
(1995-
1998)
Valve
seat
45°
451
145°
145°
(
45°
145°
angle
Correction
1
15°
15°
115°
(
15°
15°
15
angle,
outside
Correction
60°
60°
I60°
60°
I60°
I60°
angle,
inside
Va
lve
seat
width
(A)
intake
1
1
.65
±0
.25
mm
1
1.65
±0
.25
mm
1
1
.65
t
0
.25
mm
1
1
.4
-1
.9
mm
1
1
.65
±0
.25
mm
1
1
.65
±
0
.25
mm
(0
.065
+0
.014
in)
I
(0.065
t
0
.014
in)
(0
.065
:E
0
.014
in)
(0
.055-0.075
in)
(0
.065
t
0
.014
in)
l(0
.065t0
.014
in)
____
___
exhaust
12
.0
±0
.25
mm
12
.0
t
0
.25
mm
1
1
.65
t
0
.25
mm
1
1
.4
-
1
.9
mm
11
.65
±
0
.25
mm
1
1
.65
:t
0
.25
mm
(0.079
±
0
.014
in)
1
(0
.079
t0
.014
in)
1
(0
.065
±
0
.014
in)
1
(0
.055-0.075
in)
1
(0
.065
t
0
.014
in)
1
(0.065
t0
.014
in)
intake
32
.4
mm
(1
.276
in)
32
.4
mm
(1
.276m)
32
.4
mm
(1
.276
in)
32
.4
mm
(1
.276
in)
32
.4
mm
(1
.276
in)
29
.4
mm
(1
.157
in)
exhaust
30
.1
mm
(1
.185
in)
30
.1
mm
(1
.185
in)
30
.1
mm
(1
.185
in)
30
.1
mm
(1
.185
in)
29
.4
mm
(1
.157
in)
26
.4
mm
(1
.039
in)
GENERAL
......
.
.
.
.
.
.
.
.
.
...
.
.
.
.
.
.
.
.
.
.
117-1
Camshaft
timing
chains,
removing
(6-cylinder
engines)
....
.
....
..
....
..
...
.117-7
CAMSHAFT
TIMING
CHAIN,
Camshaft
timing
chains,
installing
4-CYLINDER
....
.
.
.
.
.
.
.
.
.
.
.
.......
.
...
117-2
6-clinderen
nes
117-11
Camshaft
timingchain,
removing
(
y
gi
(4-cylinder
engines)
...
..
....
..
...
...
....
117-2
VANOS
(VARIABLE
VALVE
TIMING)
.
..
117-14
Camshaft
timingchain,
installing
VANOS
system
operation,
testing
.....
.
....
117-14
(4-cylinder
engines)
...
..
...
....
..
.
.....
117-4
VANOS
control
unit,
removing
.
..
..........
117-16
CAMSHAFT
TIMINGCHAINS,
VANOS
control
unit,
installing
..
..
..........
117-17
6-CYLINDER
.
.........................
117-6
GENERAL
117
Camshaft
Timing
Chain
This
repair
group
covers
timing
chain
repair
information
for
the
4-
and
6-cylinder
engines
.
4-cylinder
enginesuse
one
double-row
chain
to
drive
the
dual
overhead
camshafts
.
See
Fig
.
1
.
Fig
.
1
.
M44
engine
valvetrain
chain
drive
.
M42
engine
is
similar
.
CAMSHAFT
TIMING
CHAIN
117-1
6-cylinder
enginesusetwo
chains
to
drive
the
camshafts
.
A
primary
chain
is
driven
off
the
crankshaft
and
drives
the
prima-
ry
sprocket
on
the
exhaustcamshaft
.
The
secondary
chain
drives
the
intake
camshaft
.
Each
chain
is
tensioned
by
a
hy-
draulic
tensioner
.
See
Fig
.
2
.
The
timing
chainsare
lubricated
by
engine
oil
and
do
not
re-`
quire
maintenance
.
A
worn
timing
chain
and
sprockets
can
lead
to
noisy
operation
and
erratic
valve
timing
.
A
faulty
ten-
sioner
can
also
cause
timing
chaín
noises
.
Primarychain
NOTE-
See
100
Engine-General
for
engine
code
and
applica-
tion
information
.
Secondary
chain
tensioner
Secondary
chain
B11115
Fig
.
2
.
Cutaway
view
of
camshaft
timing
chains
on1963
and
later
6-
cylinder
engine
with
VANOS
.
GENERAL
117-2
CAMSHAFT
TIMING
CHAIN
CAMSHAFT
TIMING
CHAIN,
4-CYLINDER
Special
BMW
service
tools
are
needed
for
timing
chain
re-
moval
and
installation
procedures
.
The
special
tools
assure
proper
timing
of
the
valvetrain
.
Precíse
marks
to
setthe
timing
on
the
camshafts
are
not
provided
for
reassembly
.
Read
the
procedures
through
before
beginning
the
job
.
CAUTION-
lf
the
camshaftsare
not
properly
timed,
the
pis-
tons
can
contact
thevalves
.
Camshaft
timing
chain,
removing
(4-cylinder
engines)
U0119-
Fig
.
3
.
Upper
timing
chain
covermounting
bolts(arrows)
.
Thermo-
1
.
Disconnect
negative
(-)cablefrom
battery
.
stat
housing
shown
removed
.
Cylinder
ídentification
sensor
(A)
also
shown
.
CAUTION-
Prior
to
disconnecting
the
battery,
read
the
battery
disconnection
cautions
given
at
the
front
of
this
manual
on
page
viii
.
2
.
Drain
engine
coolant
.
Drain
engine
block
byremoving
block
drain
.
Remove
radiator
cooling
fan
shroud
and
cooling
fan
.
See
170
Radiator
and
Cooling
System
..
WARNING
-
Allow
the
engine
to
cool
before
openingor
draining
the
cooling
system
.
CA
UTION-
On
cars
with
viscous-type
fan
clutch,
fan
has
left
hand
threads
.
NOTE-
The
block
drain
plug
is
located
on
the
exhaust
sideof
the
engine,
below
cylinder
no
.
4
.
3
.
Remove
cylinder
head
cover
.
See
113
Cylinder
HeadRemoval
and
Installation
.
NOTE-
Make
note
of
the
arrangement
of
the
rubber
insulators
when
removing
the
cylinder
head
cover
mounting
belts
.
4
.
Loosen
sparkplugs
.
See
120
Ignition
System
.
5
.
Disconnect
coolant
hoses
from
thermostat
housingon
front
of
cylinder
head
.
Unbolt
thermostat
housing
from
cylinder
head
.
6
.
Remove
cylinder
identification
sensor
from
upper
tim-
ing
chain
cover
.
Remove
upper
timing
chain
cover
.
See
Fig
.
3
.
CAMSHAFT
TIMING
CHAIN,
4-CYLINDER
7
.
Set
engine
to
approximate
TDC
by
rotating
in
normal
operating
direction
until
camshaft
lobes
at
cylinder
no
.
1
are
facing
up
and
toward
each
other
.
See
Fig
.
4
.
0011998
Fig
.
4
.
Engine
set
to
approximate
TDC
.
Cylinder
no
.
1
camshaft
lobes
face
in
and
sprocket
arrows
point
up
(arrows)
.
8
.
Remove
air
conditioning
drive
belt
.
Loosenand
push
aside
air
conditioning
compressor
.
Remove
air
condi-
tioning
compressor
mounting
bracket
.
See
640
Heat-
ing
and
Air
Conditioning
.
9
.
Remove
engine
drive
belts
and
coolant
pump
pulley
.
See
020
Maintenance
Program
.
10
.
Secure
crankshaft
vibration
damper
to
prevent
crank-
shaft
from
turning
.
Using
a
socket,
loosen
vibration
damper
hub
center
bolt
.
NOTE-
The
vibration
damper
center
bolt
is
very
tight
.
A
heavy
duty
holding
device,
such
as
BMW
special
tool
no
.
112
150,
should
be
used
to
hold
the
vibration
damper
hub
V
stationary
while
the
bolt
is
loosened
.
v
11
.
Usingloosened
bolt
at
vibration
damper,
turn
crank-
shaft
to
TDC
and
lock
in
position
by
inserting
BMW
special
tool
no
.
11
2
300
through
transmission
bell-
-
p
housing
.
See
Fig
.
5
.
v
O
NOTE-
I\
0011966a
"
If
necessary,
remove
plugfrom
locating
boye
in
lower
edge
of
bell
housing
.
"
Confirm
that
locatng
tool
has
been
correctlyinstalled
by
trying
to
rotate
the
crankshaft
.
Fig
.
7
.
Lower
timing
chain
cover
mounting
bolts
(arrows)
.
Bolts
A
Fig
.
5
.
BMW
special
tool
no
.
11
2300
installed
through
bellhousing
are
installed
through
hollow
locating
dowels
.
and
finto
flywheel
to
lock
crankshaft
at
TDC
(arrow)
.
CA
UTION-
Thecamshafts
mustbe
locked
in
the
MC
position
using
the
specialservice
tool
before
removing
the
timing
chain
.
The
tool
holds
the
camshafts
parallel
to
each
other
and
perpendicular
to
the
valve
cover
gasket
surface
.
12
.
Lockcamshafts
at
TDC
bymounting
BMW
special
tool
no
.
113
240
over
square
ends
of
camshafts
.
See
Fig
.
6
.
"
Check
that
tool
is
squarely
seated
on
cylinder
head
gasket
surface
.
If
necessary,
rotate
camshafts
slightly
using
an
open-end
wrench
at
hexon
camshafts
.
13
.
Remove
lower
timing
chaincover
mounting
bolts
and
carefully
lift
cover
off
.
Clean
sealing
surfaces
and
gas-
ket
grooves
.
See
Fig
.
7
.
14
.
Remove
hydraulic
chaintensioner
from
right
side
of
cyl-
inder
head
.
See
Fig
.
8
.
CAMSHAFT
TIMING
CHAIN
117-
3
Fig
.
6
.
BMW
special
tool
no
.
11
3240
installed
on
rearof
camshafts
to
position
camshafts
at
TDC
.
(M44
camshafts
shown
.
Other
engines
are
similar
.
Fig
.
8
.
Hydraulic
chain
tensionerplug
(arrow)
.
CAMSHAFT
TIMING
CHAIN,
4-CYLINDER
M42
Engine
CL
(EM
Fig
.
11
.
Two
versionsof
hydraulic
chaintensioners
.
Original
chain
ten-
sioner
on
M42
engine
(top)
canbe
disassembled
.
Chain
ten-
sioner
on
M44
engine
(bottom)
cannot
be
disassembled
.
Note
differences
in
outer
sleeve
.
Also,
the
M42
tensioner
de-
tent
ring
groove
is
visible
when
tensioner
is
extended
(arrow)
.
Outer
sleeve
Spring
0013024a
Detent
ring
9
.
On
M44
engines
:
Clamp
tensioner
piston
in
vice
(soft
jaws)
and
squeeze
oil
from
it
.
Slowly
compress
piston
only
up
to
end
círclip
.
Repeat
procedure
twice
to
ensure
al¡oil
is
expelled
.
See
Fig
.
13
.
10
.
Insta¡¡
hydraulic
chain
tensioner
lo
cylinder
head
.
Usea
new
sealing
washer
on
tensionerplug
when
installing
.
Tightening
Torque
"
Chain
tensioner
to
cylinder
head
....
40
Nm
(30
ft-Ib)
11
.
On
M42
engines
:
Release
early-style
chain
tensioner
by
pressing
chain
guide
against
tensioner
until
it
un-
locks
and
expands
out
.
CAMSHAFT
TIMING
CHAIN
117-
5
0012507
Fig
.
13
.
When
reinstalling
chain
tensiones,
oil
in
tensioner
piston
must
first
be
expelled
by
compressing
piston
in
vise
.
When
com-
pressing
piston,
only
compress
up
to
and
circlip
(arrow)
.
Tightening
Torque
"
Chain
sprocket
lo
camshaft
flange
(M6)
..
.
..
.............
.
..
10
Nm
(89
in-lb)
13
.
Remove
crankshaft
locking
tool
from
bellhousing
and
camshaft
locking
tool
from
rear
of
cylinder
head
.
14
.
Install
lower
timingchain
cover
:
"
Insta¡¡
new
crankshaft
oil
seal
in
cover
.
"
Use
new
gaskets
when
installing
cover
.
"
Thoroughly
clean
profile
gasketgroove
and
all
gasket
sealing
surfaces
on
lowerchaincover
.
"
Apply
a
small
bead
of
silicon
sealer
(3-Bond
1209
or
Snap
equivalent)
lo
joint
corners
where
chaincover
meets
ring
0013024
head
and
block
.
See
Fig
.
14
.
"
Tap
cover
into
position
to
engage
locating
dowels
.
Fig
.
12
.
Disassembled
early-style
chain
tensioner
usadon
M42
en-
"
Tighten
cover
mounting
bolts
alternately
and
in
stages
.
gine
.
12
.
Check
that
chain
is
now
free
of
siack
.
Tighten
down
sprocket
mounting
bolts
.
where
chain
cover
meets
head
and
block
(arrows)
.
Fig
.
14
.
Apply
sealer
(3-Bond
1209
0
or
equivalent)
to
joint
corners
CAMSHAFT
TIMING
CHAIN,
4-CYLINDER
117-
6
CAMSHAFT
TIMING
CHAIN
15
.
Insta¡¡
upper
timing
chaincover
:
17
.
Remove
crankshaft
locking
tool
from
transmission
bell-
"
Thoroughly
clean
profile
gasketgroove
and
all
sealing
housing
and
camshaft
locking
tool
from
rear
of
cylinder
surfaces
.
head
.
"
Applya
small
bead
ofsilicon
sealer
(3-Bond
1209®
or
equivalent)
to
upper
and
lower
joint
comers
where
18
.
Turn
engine
over
by
hand
in
direction
of
rotation
at
least
chaincover
meets
cylinder
head
.
two
full
rotations
.
Reinstall
camshaft
and
crankshaft
"
Insta¡¡
new
profile
gasket
to
groove
in
lowerchain
cover
.
locking
tools
to
check
engine
timing
.
Repeat
cam
timing
"
Protect
top
of
profile
gasket
using
thin
sheetmetal
procedure
if
tools
do
not
fit
easily
into
position
.
Remove
(BMW
special
tool
no
.
11
2
330
or
equivalent)
.
See
locking
tools
.
Fig
.
15
.
"
Attach
new
gaskets
to
cover
with
light
dabs
of
gasket
19
.
Install
cylinder
head
cover
as
described
in
113
Cylin-
sealant,
hold
gaskets
in
placeusing
cover
mounting
der
HeadRemoval
and
Installation
.
screws
.
"
Place
upper
timing
cover
into
position
.
Snug
down
al¡
NOTE-
screws,
without
tightening
.
Carefully
slide
out
sheet
OnM44
engines,
note
oil
supply
O-ring
and
replace
ff
metal
.
necessary
.
"
Temporarily
install
cylinder
head
cover
without
gasket
.
Insta¡¡
and
tighten
at
least
two
cylinder
head
cover
mounting
bolts
to
seat
upper
timing
chaincover
.
"
Tighten
all
upper
timing
cover
screws
.
Tightening
Torque
"
Remove
valve
cover
.
"
Cylinder
head
cover
to
cylinder
head
(M6
screws)
...
..
.
.
10
Nm
(89
ín-Ib)
-
CAMSHAFT
TIMING
CHAINS,
Fig
.
15
.
When
installing
upper
timing
chain
cover,
use
thin
sheetmetal
6-CYLINDER
(arrow)
to
protect
profile
gasket
when
installing
uppercover
.
Tightening
Torque
"
Upper
timing
chaincover
to
engine
block
or
cylinder
head
(M6
screws)
....
.
..
10
Nm
(89
in-lb)
16
.
Install
vibration
damper
while
aligning
woodruff
key
.
Hold
crankshaft
stationary
and
tighten
mounting
bolt
.
Tightening
Torques
I
CAUTION-
"
Pulley
to
vibration
damper
..
.
.
.
....
22
Nm
(17
ft-Ib)
lf
the
camshaftsare
not
properly
timed,
the
1
pis-
tons
can
contact
thevalves
.
"
Vibration
damper
tocrankshaft
M16
stretch
bolt
(always
replace)
.
330
Nm
(244
ft-Ib)
CAMSHAFT
TIMINGCHAINS,
6-CYLINDER
20
.
Installation
of
remaining
parts
is
reverse
of
removal
.
When
installing
thermostat,
make
sure
arrow
or
vent
hole
faces
up
.
Refill
cooling
system
as
described
in
170
Radiator
and
Cooling
System
.
Tighteníng
Torques
"
Coolant
drain
plug
to
cylinder
block
.
..
.
.
.
...
.
..
.....
25
Nm
(18
ft-Ib)
"
Radiator
cooling
fan
to
coolant
pump
.
..
.
...
...
..
.....
40
Nm
(30
ft-Ib)
"
Radiator
drain
screw
to
radiator
....
2
.5
Nm
(22
in-lb)
Camshaft
timing
chainremovalon
6-cylinder
engines
re-
quires
that
you
Rmove
the
engine
oil
pan
by
raising
the
en-
gine
and/or
lowering
the
front
suspension
crossmember
.
Special
BMW
service
tools
are
needed
for
timing
chain
re-
moval
and
installation
procedures
.
The
special
tools
assure
proper
timing
of
the
valvetrain
.
Precise
marks
to
setthe
timing
on
the
camshafts
arenot
provided
for
reassembly
.
Read
the
procedures
through
before
beginning
thejob
.
Camshaft
timing
chains,
removing
(6-cylinder
engines)
1
.
Disconnect
negative
(-)
cable
from
battery
.
CA
UTION-
Disconnecting
the
battery
may
erase
fault
codes)
stored
in
control
module
memory
.
Check
for
fault
codes
using
special
BMW
diagnostic
equipment
.
2
.
Drain
engine
coolant
.
Drain
engine
block
by
removing
block
drain
.
Remove
radiator
cooling
fan
shroud
and
cooling
fan
.
See170
Radiator
and
Cooling
System
.
.
WARNING
-
Allow
the
engine
to
cool
before
openingor
draining
the
system
.
CAUTION-
Radiator
fan
has
left
hand
threads
.
NOTE-
The
block
drain
plug
is
located
on
the
exhaust
side
of
the
engine,
below
cylinder
no
.
4
.
3
.
Drain
engine
oíl
andremove
oil
pan
.
See
119
Lubrica-
tion
System
.
4
.
Remove
alternator
cooling
duct
.
5
.
Remove
two
large
coolant
hoses
from
thermostat
housing
.
Remove
engine
lifting
bracket
and
thermostat
housing
from
front
of
cylinder
head
.
6
.
Loosen
bolts
for
coolant
pump
pulley
.
Then
remove
drive
belts
for
alternator
andA/C
compressor
.
See
020
Maintenance
Program
.
Remove
coolant
pump
pulley
.
Fig
.
16
.
NOTE-
OnM50
engines
with
a
two-roller
drive
belt
tensioner,
remove
the
upper
rollerto
access
thetensioner
mount-
ing
bolts
.
NOTE-
Make
note
of
the
arrangement
of
the
rubber
insulators
when
removing
the
cylinder
head
cover
mounting
bolts
.
CAMSHAFT
TIMING
CHAIN
117-
7
Fig
.
16
.
Drive
belt
tensioner
mounting
bolts
(arrows)
.
B11055
7
.
Remove
drive
belt
tensioner
from
front
of
engine
.
See
Fig
.
17
.
1992-1995
M50
engine
speed
sensor
on
timing
cover
(ar-
row)
.
10
.
Unclip
andremove
baffle
cover
from
above
intake
cam-
shaft
.
See
Fig
.
18
.
11
.
On
1992
engines
:
Remove
upper
timing
chain
cover
from
front
of
cylinder
head
.
See
Fig
.
19
.
8
.
Remove
engine
speed
sensor
from
lower
timing
chain
12
.
Loosen
spark
plugs
.
See
120
Ignition
System
.
cover,
if
applicable
.
See
Fig
.
17
.
13
.
Set
engine
to
approximate
TDC
by
rotating
in
normal
9
.
Remove
cylinder
head
cover
.
See
113
Cylinder
Head
operating
direction
until
camshaft
lobes
at
cylinder
no
.
Removal
and
Installatíon
.
1
are
facing
each
other
.
See
Fig
.
20
.
14
.
Set
engine
to
TDC
by
aligning
"0/T'
mark
(0°TDC)on
front
vibration
damper
with
cast
bosson
lower
timing
chain
cover
.
See
Fig
.
21
.
15
.
Remove
vibration
damper
mounting
bolts
and
remove
vibration
damper
and
pulley
.
See
Fig
.
22
.
CAMSHAFT
TIMING
CHAINS,
6-CYLINDER