1995 BMW M3 table

al
Icld

Table
e
.
Engine
Driveability
Troubleshooting

c
l



1



I



f



I



I
Oxygen
sensor
faulty



Test
oxygen
sensor
.

ENGINE-GENERAL
100-
1
5

SYMPTOMS

a
.
Engine
fafs
tostart

b
.
Engine
startsbut
stops
immediately

c
.
Erratic
engine
idle

d
.
Poor
engine
responseon
acceleration

e
.
Erratic
engine
operation
in
al¡
speed
ranges

f
.
Excessive
fuel
consumption
g
.
Poor
enginepower,
fails
to
rev
up
h
.
CO
content
toolow

i.
CO
content
too
high

CAUSES



CORRECTIVE
ACTION

a



Fuel
pump
faulty



Test
fuel
pump
.
Repair
Group
160

a



e



Ignition
system
faulty



Test
ignition
system
.
Repair
Group
120
a



Main
relay
or
fuel
pump
relay
faulty



Test
main
relay
.
Repair
Group
130
a



Crankshaft/rpm
position
sensor
faulty



Test
crankshaft/rpm
sensor
.
120
b



c



h



i



ldle
speed
control
valve
faulty



Test
idle
speed
control
valve
.

c



d



e



Throttle
position
sensor
faulty
or
idle
signal
to



Test
throttle
position
sensor
.
DME
control
module
missing
.

c



d



h



i



Mass
air
flow
sensor
faulty



Test
mass
air
flow
sensor
Repair
Group
130
a



b



c



d



e



h



Large
air
intake
system
leak



Check
for
major
intake
air
leaks
downstream
of
mass
air
flow
sensor
.

a



c



d



e



g



h



Fuel
pressure
too
low



Test
fuel
pressure
.
Repair
Group
130

?



I



F
ue
l
pr
essu
r
e
t
oo
high



T
est
f
u
el
pressure
.
Repair
Group
130
d



e



g



h



Fuel
pump
delivery
volume
too
low



Test
fuel
pump
delivery
volume
.
Repair
Group
160
a



c



e



f



h
q
C
oo
l
a
nt
t
e
mp
e
r
a
t
u
r
e
se
n
so
r
f
au
lty



--]
T
est
coo
l
a
n
t
temp
erature
sensor
.

c



e



~



f



i



~
Fuel
injectors
leaking



Check
fuel
injectors
and
replace
leaking
injectors
.

~
Repair
Group
130

Throttle
plate
binding
or
incorrectly
adjusted



Check
throttle
plate
and
adjust
if
necessary
.

a



c



Electrical
connections
loose,
broken,
or
cor-



Visually
inspect
connectors
and
correct
any
roded



faults
.
Repair
Group
600
Ground
connections
loose,
broken,
or
corroded



Visually
inspect
ground
connections
and
correct
any
faults
.
Repair
Group
600

c



e
~



f



CO
content
too
high



Test
air
flowor
mass
air
flow
sensor
.
Repair

~
Group
130
a



b



c



d



e



CO
content
too
low



Test
mass
air
flow
sensor
.
gb



c



d



e



f



g



h



i



Inputsignals
to
ECM
missing,
ECM
in
limp



Make
electrical
tests
at
DMEECM
relay
.
Repair

home
mode



Group
130
a
~
b
~
c
~
d



e]



f



g



h



i



ECM
faulty



Test
DMEECM
inputs
.
If
all
inputs
are
correct,
replace
ECM
.

DRIVEABILITY
TROUBLESHOOTING

7
.
Lightly
lubricate
new
cylinder
head
bolts
.
Loosely
instan
bolts
and
their
washers,
then
thread
them
in
until
they
are
finger
tight
.

NOTE-

Check
that
all
washers
for
the
cylinder
head
bolts
are
in
place
before
installing
the
bolts
.

8
.
Tighten
cylinder
head
bolts
in
correct
sequence
.
See
Fig
.
17
.

UU125U2

Fig
.
17
.
Cylinder
head
bolt
tightening
sequence
for
4-cylinder
en-
gines
.
Note
oil
supply
tube
seal
(arrow)
on
M44
engine
.

WARNING
-

The
bolts
should
be
tightennd
in
three
stages
as
líst-
ed
below
.
The
final
stages
require
the
use
of
a
spe-

cial
tool
(BMW
tool
No
.
11
2
110)
ora
suitable

protractor
to
tighten
the
bolts
to
a
specified
torqueangle
.
See
Fig
.
18
.

Tightening
Torques

"
Cylinder
head
to
engine
block
(Torx
El2
M10
bolts)

Stage
1



.
.
.....
.
.
.............
30
Nm
(22
ft-Ib)

Stage
2



.
...
...
.
.
...................
..
.
+90°

Stage
3
.....
...
.
..
...................
..
+90°

9
.
Carefully
rotate
crankshaft
in
direction
of
engine
rota-
tion
and
lock
it
at
TDC
by
inserting
BMW
special
tool

no
.
11
2
300
through
transmission
bellhousing
.
See

Fig
.
19
.

CYLINDER
HEAD
REMOVAL
AND
INSTALLATION



113-
7

Fig
.
18
.
Protractor
and
pointer
being
used
to
tighten
bolts
to
specified
torqueangle
(6-cylinder
engine
shown)
.

Fig
.
19
.
BMW
special
tool
11
2
300
inserted
through
bellhousing
hole
and
finto
flywheel
(arrow)
to
lockcrankshaft
at
TDC
.

10
.
Turn
left
chainguide
adjusting
sleeve
in
until
it
just
con-

tacts
the
cylinder
head
(See
Fig
.
14
.)
.
Insert
chain
guide
retaining
screw
and
tighten
.

CAUTION-



11
.
Placechain
sprockets
with
chains
oncamshaftsso
that
Be
sure
timing
chain
does
not
bind
oncrank
gear

when
turning
crankshaft
.



arrowson
sprockets
point
up
and
elongated
holes
in

sprocketsare
centered
to
tapped
holes
in
camshafts
.

See
Fig
.
20
.

CYLINDER
HEAD,
4-CYLINDER

113-16



CYLINDER
HEAD
REMOVAL
AND
INSTALLATION

NOTE-

Check
that
all
washers
for
the
cylinder
head
bolts
are
in
place
before
installlng
the
bolts
.
Some
of
the
washers
may
be
staked
to
the
cylinder
head
.

6
.
Tighten
cylinder
head
bolts
in
correct
sequence
.
See
Fig
.
41
.

Fig
.
41
.
Cylinder
head
bolt
tightening
sequence
for
M50
engine
.

Fig
.
42
.
Protractor
and
pointer
being
used
to
tighten
bolts
to
specified
torque
angle
.

WARNING
-

The
bolts
should
be
tightened
in
three
stages
as
list-
ed
below
.
The
final
stages
require
the
use
of
aspe-
cial
tool
(BMW
tool
No
.
11
2
110)
ora
suitable
protractor
to
tighten
the
bolts
to
a
specified
torque
angle
.
See
Fig
.
42
.

CYLINDER
HEAD,
6-CYLINDER

7
.
Install
and
tighten
cylinder
head-to-lower
timing
chain

cover
bolts
.

Tightening
Torques

"
Cylinder
head
to
engine
block(Torx
El
2
Ml
0
bolts)

Stage
1
.........
..
.
.
.
...
.
...
..
30
Nm
(22
ft-Ib)

Stage
2
.........
..
..
....
.
...
..........



+90°

Stage
3
...
.
.....
..
.
.
.
...
.
...
..........
.+90°

"
Cylinder
head
lo
lower
timing

chaincover
.......
..
..
..
...
.
....
10
Nm
(89
in-lb)

8
.
Carefully
rotate
crankshaft
in
direction
of
engine
rota-tion
and
lock
it
at
TDC
by
inserting
BMW
special
tool
no
.
11
2
300
through
transmission
bellhousing
.
Guide
primary
timing
chain
to
keep
it
from
jamming
on
crank
gear
.

9
.
Mount
primary
chain
sprocketto
primary
chain
so
that

arrowon
sprocket
faces
up
.
Mount
sprocket
to
exhaust
camshaftso
tapped
holes
in
camshaft
are
on
left
most
side
of
elongated
holes
in
sprocket
.
See
Fig
.
43
.

Fig
.
43
.
Primary
chain
sprocket
correctly
afgned
to
exhaust
cam-
shaft
.
Camshaft
holes
should
be
on
left
most
sideof
sprocket
holes
.

10
.
Install
timing
chain
guide
and
secondary
chain
tension-er
.
Tighten
mounting
bolts
.

11
.
Install
asan
assembly,
secondary
chain
sprockets
and
chain
so
that
arrow(s)
on
sprockt(s)
are
pointing
up
.
Centermounting
holes
in
sprockets
tobolt
holes
in
camshafts
.
See
Fig
.
44
.

12
.
Install
thrust
washers
and
spring
plate
(if
applicable)
to
sprockets
.
See
Fig
.
45
.

GENERAL

CYLINDER
HEAD,

DISASSEMBLY
AND
ASSEMBLY
CYLINDER
HEAD
AND
VALVETRAIN



116-1

116
Cylinder
Head
and
Valvetrai
n

GENERAL
.
.....
.
.
.
...
.
.
.
.
.
.
.
.
.
.......
116-1



Hydraulic
cam
followers,
checking
and
replacing
(M42
and
al¡
6-cylinder
engines)
.
...
.....
.
..
116-9
CYLINDER
HEAD,



Valve
guides
.
.
.
...
.
.
.
.
.
.
...
.
.
.
.
.
.
.
.
.
.
116-10
DISASSEMBLY
AND
ASSEMBLY
...
.
...
116-1



Valves
.
.
.
.
.
.
.
.
.
.
.
.
.
...
.
...
.
.
.
.
.
...
.
.
116-11
Camshafts,
removing
and
installing

(M42
engine)
....
.
....
.
.
.
.
.
.
.
.
.
.....
.
.
116-1



Valves,
leak
test
.
.
.
.
.
.
.
.
.
.
...
.
.
.
.
.
.
.
.
.
.
116-11

Camshafts,
removing
and
installing



Valve
stem
oil
seals
.
.
.
.......
.
.
.
.
.
...
.
.
116-11

(M44
engine)
.........
.
.
.
.
.
.
.
.
.
.......



116-3



Valve
seats



.
.
.
.
.
.
.
.
.
...
.
...
.
.
.
.
.
...
.
.116-12

Camshafts,
removing
and
installing



Valve
springs
.
.
.
.
.
.
.
.
...
.
...
.
.
.
.
.
.....
116-12

(6-cylinder
engine)
.....
.
.
.
.
.
.
.
.
.
.......
116-4

Valves,
removing
and
installing
........
.
....
116-6



TABLES

CYLINDER
HEAD
AND
VALVETRAIN,



a
.
Cylinder
Head
Height
........
....
.
..
..........
116-7

RECONDITIONING
.
...
.
.
.
.
.
.
.
.
.
.......
116-7



b
.
Camshaft
Specifications
.......
..
.
..
........
.116-7

Cylinder
head
...
.
.
.
...
.
.
.
.
.
.
.
.
.
....
.
..
116-7



c
.
Valve
Guide
Specifications
....
...
.
..
........
116-10
d
.
Valve
Specifications
...........
..
.
..
........
116-11
Camshaft
.
.
.
.
.
.
.
.
.
.
.
.
.
.
...
.
.
.
.
.
.......
116-7



e
.
Valve
Seat
Dimensions
.........
.
..
..
......
.116-12
Hydraulic
valve
adjusters,

checking
and
replacing
(M44
engine)
..
.
.
.
116-8

Camshafts,
removing
and
installing

(M42
engine)

This
repair
group
covers
cylinder
head
and
valvetrain
ser-
vice
and
repair
.
Most
of
the
repairs
described
here
require
that



The
camshafts
can
be
removed
with
the
cylinder
head
the
cylinder
head
first
be
removed
as
described
in
113
Cylin-



mounted
on
the
engine
.
The
first
step
is
to
remove
the
cylinder
der
HeadRemoval
and
Installation
.



head
cover
.
See
113
Cylinder
HeadRemoval
and
Installa-

tion
.

NOTE-



Special
BMW
service
tools
should
always
be
used
to
remove

"
For
timing
chain
and
VANOS
repair
information,
see



and
install
the
camshafts
.
Removal
and
installation
of
the
cam-
117
Camshaft
Timing
Chain
.



shafts
without
the
special
tools
can
result
in
camshaft
and
valve

"
If
it
is
determined
that
the
cylinder
head
will
require



train
damage
.

significant
reconditioning
work,
a
remanufactured
cyl-

inder
head
may
bea
good
alternative
.
Remanufac-



WARNING-

tured
cylinder
heads
are
available
froman
authorized



The
process
of
evenly
loosening
the
camshaftbear

BMW
dealer
.



ing
cap
nuts
is
NOT
an
acceptable
method
of
re-
moving
the
camshafts
.
Be
sure
to
read
the

The
information
given
in
this
repair
group
is
organized
ac-



procedure
through
before
starting
the¡ob
.

cording
to
engine
code
.
For
engine
applicationinformation,

see100
Engine-General
.



1
.
Disconnect
negative
(-)
battery
cable
.

CAUTION-

Prior
to
disconnectiog
the
battery,
read
the
battery
disconnection
cautions
given
at
the
front
of
this
manualonpage
viii
.

BMW
special
tools
are
required
for
most
cylinder
head
ser-



2
.
Remove
radiator
cooling
fan
shroud
and
cooling
fan
.
vice
described
in
this
repair
group
.
Many
of
these
tools
areex-



See
170
Radiator
and
Cooling
System
.
pensive
and
only
available
through
an
authorized
BMW
dealer
.
If

the
special
tools
are
not
available,
one
altematve
is
to
remove

the
cylinder
head
and
have
it
disassembled
byan
authorized



CAUTION-

BMW
dealer
.
Be
sure
to
read
each
procedure
thoroughlybefore



Radiator
fa
n
has
left
hand
threads
.

starting
a
job
to
determinewhich
special
tools
and
equipment
will

be
necessary
.

CYLINDER
HEAD,
DISASSEMBLYANDASSEMBLY

Camshaft
installation
waíting
times

"
Ator
above
68°F
(20°C)
............
.
..
10
minutes

"
50-68°F
(10-20°C)
................
..
.
30
minutes

"
32-50°F
(0-10°C)
.
.......
.
.........
..
.
75minutes
"
Reinstall
timing
chain
sprockets
and
tensioner
as
spe-

cifically
described
in
117
Camshaft
Timing
Chain
.



i

"
Wait
at
least
10minutes
before
cranking
engine
over

with
starter
motor
for
the
fi+



1
1/
/~~
.0
time
.

Tightening
Torques

"
Camshaft
bearing
caps

to
cylinder
head
(M7)
.............
15
Nm
(11
ft-Ib)

"
Cylinder
head
cover

to
cylinder
head
(M6)
.............
10
Nm
(89
in-lb)

"
Primary
timing
chain
tensioner
plug

to
cylinder
head
..
..
..
...........
40
Nm
(30
ft-Ib)

(see
117
Camshaft
Timing
Chain)

"
Spark
plugs
(M12)
..
.
.............
23
Nm
(17
ft-Ib

"
Timing
chain
cover
(upper)

to
cylinder
head
..
.
.
...
..........
10
Nm
(89
in-lb)

"
Timing
chainsprockets
to
camshaft

M6
........
.
...
.
..
.



..........
10
Nm
(7.5
ft-Ib)

M7



............
.
..
..
...........
15
Nm
(11
ft
.lb)

(see
117
Camshaft
Timing
Chain)

Camshafts,
removing
and
installing

(M44
engine)

Special
BMW
service
tools
should
always
be
used
to
remove

and
install
the
camshafts
.
Removal
and
installation
of
the
cam-

shafts
without
the
special
tools
can
result
in
camshaft
and
val-

vetrain
damage
.

1.
Disconnect
negative
(-)
battery
cable
.

CAUTION-

Prior
to
disconnecting
the
battery,
read
the
battery
disconnection
cautions
given
at
the
front
of
this

manual
on
page
vi¡¡
.

CYLINDER
HEAD
AND
VALVETRAIN



116-
3

2
.
Remove
spark
plugs
.
See
1201gnition
System
.

3
.
Rotateengine
until
a
pair
of
camshaft
lobes
are
point-
ing
up
.
Using
BMW
special
tool
115
130,
depresseach
valve
and
valve
spring
enough
to
remove
rocker
arms
.

Rotate
engine
for
the
next
pair
of
rocker
arms
.
See
Fig
.

3
.

cover
.

Fig
.
3
.



BMW
special
tool
no
.
11
5130
(arrow)
being
used
to
depress
valve
stem
to
remove
rocker
arm
.

WARNING
-

Removed
rocker
arms
must
be
reinstalled
in
the
same
locations
.

4
.
Remove
primary
timing
chain
tensioner
from
right
side

of
cylinder
head
.

The
camshafts
can
be
removed
with
the
cylinder
head



5
.
Remove
upper
timing
chaincover
.

mounted
onthe
engine
.
The
first
step
is
to
remove
the
cylinder

head
cover
.
See
113
Cylinder
HeadRemoval
and
Installa-



NOTE-

tion
.



lt
is
not
necessary
to
remove
the
lower
timing
chain

6
.
Remove
timing
chain
sprockets
with
timing
chains
from

front
of
camshafts
.
See
117
Camshaft
Timing
Chain
.

Remove
upper
timing
chain
guide
from
cylinder
head
.

WARNING-



7
.
Remove
camshaft
bearing
caes
and
remove
cam
The
process
of
evenly
loosening
the
camshaft
bear-



shafts
.
ing
cap
nuts
is
NOT
an
acceptable
method
of
re-

moving
the
camshafts
.
Be
sure
to
read
the



CAUTION-
procedure
through
before
starting
the
job
.
Camshaft
bearing
capsmust
be
reinstalled
intheir

original
locations
.

CYLINDER
HEAD,
DISASSEMBLYAND
ASSEMBLY

116-
4



CYLINDER
HEAD
AND
VALVETRAIN

NOTE-

"
The
camshaft
bearing
caps
are
coded
with
a
letter
anda
number
.
Forexample,
'541"is
the
exhaustcam-
shaft
bearing
cap
at
the
front
of
the
engine,
and
`El"
is
the
intake
camshaft
bearing
cap
at
the
front
of
the
engine
.

"
Camshafts
are
stamped
with
a
code
letter-'E"
for
the
intakeside
and
A"
for
the
exhaust
side
.

"
"E"
isfor
Einla3,
(German
for
intake)
and
A"
is
for
Auspuff,
(Germen
for
exhaust)
.

"
The
front
of
the
engine
is
at
the
front
of
the
car
.

8
.
Camshaft
installation
is
reverse
of
removal,
noting
the

following
:

"
Prior
to
installation,
check
all
components
for
wear
as

described
below
underCylinder
Head
and
Val-

vetrain
Reconditioning
.
"
Lubricate
camshafts
prior
to
installation
.
"
Reinstall
timing
chain
sprockets
and
tensioner
and
set
valve
timing
before
reinstalling
rocker
arms,as
spe-

cifically
described
in
117
Camshaft
Timing
Chain
.

"
Be
sure
corresponding
camshaft
lobe
is
pointing
up

before
installing
rocker
arms
.
Note
that
each
rocker
arm
angles
away
from
corresponding
spark
plug
hole
.
See
Fig
.
4
.

"
Wait
at
least
10
minutes
for
hydraulic
cam
followers
to
fully
compress
before
cranking
engine
over
with
start-

er
for
the
first
time
.

Tightening
Torques

"
Camshaft
bearing
caps

to
cylinder
head
(M7)
.............
15
Nm
(11
ft-Ib)

"
Cylinder
head
cover

to
cylinder
head
(M6)
.............
10
Nm
(89
in-lb)

"
Primary
timing
chain
tensioner
plug

to
cylinder
head
.
................
40
Nm
(30
ft-lb)
(sea
117
Camshaft
Timing
Chain)

"
Spark
plugs
(M12)
.............
...
23
Nm
(17
ft-lb

Timing
chaincover
(upper)
to
cylinder
head
M6
.....
.
.
...
................
.
10
Nm
(7
.5
ft-Ib)
M7
....
..
.
.
........
.
.....
.
...
.
15
Nm
(11
ft-Ib)

"
Timing
chain
sprockets
to
camshaft

M6
....
.
.
..
..............
.
..
..
10
Nm
(7
.5
ft-Ib)
M7
....
....
..............
.
..
..
.15
Nm
(11
ft
.lb)
(sea
117
Camshaft
Timing
Chain)

Camshafts,
removing
and
installing

(6-cylinder
engine)

Camshafts
on
6-cylinder
engines
can
be
removed
with
the
cylinder
head
mounted
on
the
engine
.
The
first
step
is
to
re-
move
the
cylinder
head
cover
.
See
113
Cylinder
Head
Re-
moval
and
Installation
.

CYLINDER
HEAD,
DISASSEMBLYAND
ASSEMBLY

Fig
.
4
.



Correct
installation
position
ofrocker
arms
(arrows)
on
M44
engine
.

Special
BMW
service
tools
should
always
be
used
to
re-

move
and
instan
the
camshafts
.
Removal
of
camshafts
with-

outthe
special
tools
can
result
in
personal
injury
and/or
cylinder
head
damage
.

WARNING
-

The
processof
evenly
loosening
the
camshaft
bear-
ing
cap
nuts
is
NOT
en
acceptable
method
of
re-
moving
the
camshafts
.
Special
tools
shouldalways
be
used
lo
remove
the
camshafts
.
Be
sure
to
read
the
procedure
through
before
starting
ajob
.

1
.
Disconnect
negative
(-)
battery
cable
.

CAUTION-

Prior
to
disconnectiog
the
battery,
read
the
battery
disconnection
cautions
given
at
the
front
of
this
manual
onpaga
viii
.

516
2
.
Setengine
to
TDC
and
lock
into
position
by
installing
BMW
special
tool
11
2
300
through
transmission
bell-
housing
and
into
hole
in
flywheel
or
drive
platea
See
Fig
.
5
.

NOTE-

Arrows
on
camshaft
sprockets
shouldbe
pointing
up
.
Sea
117
Camshaft
Timing
Chain
.

3
.
Remove
VANOS
control
unit
from
cylinder
head
.
Re-
move
timing
chainsprockets
from
camshafts
.
See117

Camshaft
Timing
Chain
.

4
.
Remove
sparkplugs
and
insta¡¡
BMW
special
tool
11
3
260/11
3
270
to
cylinder
head
.
Tighten
tool
retaining
bolts
in
spark
plug
holes
.
Do
not
ovar-tighten
bolts
.
See
Fig
.
6
.

CYLINDER
HEAD
AND
VALVETRAIN,

RECONDITIONING

Thís
section
provides
the
specifications
and
special
recon-
ditioning
information
necessary
to
repair
the
cylinder
heads

covered
by
this
manual
.

If
machine
shop
services
are
not
readily
available,
one
al-

ternative
is
to
install
a
remanufactured
cylinder
head
froman

authorized
BMW
dealer
.

Cylinder
head

NOTE-

When
replacing
the
cylinder
headon
engines
with
re-
movablecamshaft
carriers,
be
sure
to
check
the
cam-
shaft
carrier
bearing
surfaces
for
warpage
.

4-cylinder



1
140
.0
mm
(5
.512
in)



1
139
.55
mm
(5
.494
in)

6-cylinder



1



140
.0
mm
(5
.512
in)



1



139
.7
mm
(5
.500
in)

CYLINDER
HEAD
AND
VALVETRAIN



116-
7

A

The
disassembled
cylinder
head
should
be
inspected
for



Fig
.
9
.



Front
víew
of
cylinder
head
showing
minimum
resurfacing
di-

warpage
and
cracks
.
Check
the
valve
guides
and
valveseats



mension
(A)
.

for
wear
before
machining
a
warped
head
.
Always
decarbon-

ize
and
clean
the
head
before
inspectiog
it
.
A
high-quality



Camshaft

straíght
edge
can
be
used
to
check
for
warpage
.
Camshaft
wear
is
usually
caused
by
insufficient
lubrication
.

Visually
inspect
the
cylinder
head
for
cracks
.
If
acracked



Visually
inspect
the
camshaft
lobes
and
journals
for
wear
.

cylinder
head
is
suspected
and
no
cracks
are
detected



Camshaftwear
specifications
are
given
in
Table
b
.

through
the
visual
inspection,
have
the
head
further
tested
for

cracks
byan
authorized
BMW
dealer
.
A
cracked
cylinder
head



Table
b
.
Camshaft
Specifications

must
be
replaced
.



4-cylinder
engines

Axialplay
M42
engine



0
.065-0
.150
mm
(0
.0025-0
.0059
in)

M44
engine



0
.065-0
.150
mm
(0
.0025-0
.0059
in)

Radial
play(Plastigage)



0
.020-0.061
mm
(0
.0008-0
.0024
in)
M42
engine
M44
engine



0
.040-0
.082
mm
(0
.0016-0
.0032
in)

6-cylinder
engines
A
warped
cylinder
head
can
be
machined
provided
no



Axial
pla
y
more
than
0
.3
mm
(0
.012
in)
of
material
is
removed
.
If
further



All



0
.020-0.054
mm
(0
.0008-0
.0021
in)

machining
is
required,
the
head
should
be
replaced
.
Remov-



Radial
play(Plastigage)
0
.150-0.330
mm
(0
.006-0.013
in)
ing
more
than
this
amount
will
reduce
the
size
of
the
combus-



All

tion
chamber
and
adversely
affect
engine
performance
.
A
0
.3

mm
thicker
gasket
is
available
from
an
authorized
BMW
parts

department
for
machined
heads
.



NOTE-

-
On
M44
engines,
check
the
oil
sprayer
tube
in
the
top
Before
machining
the
head
to
correct
for
warpage,
measure



of
the
cylinder
head
coverand
the
tubesea¡
in
the
cyl-

the
total
height(thicknessof
the
cylinder
head)
.
See
Fig
.
9
.



inderhead
.Acloggedsprayertubeoradefectiveseal

Minimum
height
specifications
are
given
in
Table
a
.



will
reduce
oil
flowto
the
camshaft
.
See
Fig
.
10
.

-
If
the
camshaft
is
being
replaced
due
to
cam
lobe
Table
a
.
Cylinder
Head
Height



wear,
the
corresponding
rockerarms
orcam
followers

Engine



New



Minimum
height



shouId
also
be
replaced
to
avofd
damaglng
the
new

(dimension
A)



camshaft
.

CYLINDER
HEAD
AND
VALVETRAIN,
RECONDITIONING

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)