BMW 1989-1995 525i Service Manual page 99

CYLINDER HEAD AND VALVETRAIN
116 Cylinder Head and Valvetrain
116-1
GENERAL
11 6-1
CYLINDER HEAD COVER
GASKET REPLACEMENT
116-2
To replace cylinder head
cover gasket (M20 engine) . . . . . . . . . . . . . . . 116-2
To replace cylinder head
cover gaske t (M30 engine) . . . . . . . . . . . . . . . 116-2
To replace cylinder head
cover gaske t (M50 engine) . . . . . . . . . . . . . .. 11 6-3
To replace cylinder head
cover gaskets (M60 engine) . . . . . . . . . . . . .. 116-5
VALVE ADJUSTMENT
(M20
and
M30
Engines)
116-6
To adjust valve clearance . . . . . . . . . . . . . . . . . 116-6
CYLINDER HEAD DISASSEMBLY
AND ASSEMBLy
116-7
To disassemble cylinder head
(M20 engine ) . . . . . . . . . . . . . . . . . . . . . . . . .. 116-7
To disassemble cylinder head
(M30 engine) 116-10
To disassemble cylinder head
(M50 engine ) 116-11
To disassemble cylinder head
(M60 engine ) 116-13
GENERAL
This repair group covers cylinder head and valvetrain ser-
vice and repair. Most of the repairs described here require that
the cylinder head first be removed as described in 113 Cylin-
der Head Removal and Installation.
NOTE -
• For timing chain repair intormetic n on
535i
moaets
(M30 engines) and 1991 and later 525i models (M50
and M50TU engines). see 117 Camsh aft Tim ing
Chain . For timing belt repair information on 1989 and
1990 525i modets (M20 engine). see 118 Camshaft
Timing Bell.
• The 1993 and tater 525i models (M50TU engines) are
equipped
witt: a
DME-contro lled variable valve liming
system called VANOS. Repair information on this sys -
tem is covered in 117 Camshaft Tim ing Cha in .
Special lools are required for most cylinder head service. dis-
assembly. and reconditioning described in this repair group_Be
sure to read each procedure thoroughly betore starting a job to
determine which tools and equipment will be necessary.
CYLINDER HEAD AND
VALVETRAIN RECONDITIONING
116-15
Cylinder Head 116-15
Camshaft _ 116-16
Hydraulic Cam Followers
(M50/M60 eng ines) 116- 17
To check hydraulic cam followers 116-17
Rocker Arms and Rocker Arm Shafts
(M20 and M30 eng ines) _ 116-1 7
Valve Gu ides 116-18
Valves 116-18
Testing Valves for Leakage 116-18
Valve Stem Oil Seals 116-18
Valve Seats 116-19
Valve Springs 11 6-20
TABLES
a. Engine Application Codes
116-1
b. Valve Clearance Specifications
116-7
c. Camshaft Identification (M60 Engine)
116-15
d. Cylinder Head Height
116-16
e. Camshaft Specifications 116-16
f. Valve Guide Specifications
116-19
g. Valve Specifications _ _. _ _
116-19
h. Valve Seat Dimensions 116-21
i. Valve Seat Replacement Specifications
116-22
NOTE -
If
it is determined that the cylinder head will require sig-
niticsn t reconditioninq work.
a
remanufactured cylinder
head may be
a
good alternative. Remanulactured cyt-
inder heads are available Irom an authorized BM W
dealer.
The information given in this repair group is organ ized ac-
cording to engine code . Table a is a basic list of engine appli-
cation code s. For additional engine applicat ion information.
see 100 Engine-General.
Table a. Engine Application Codes
Mod el Engin e code
-
525i/525iT
1989 -1 990 1,,120 (single overhead cam . 2.5 liter)
1991-1992 1,,150 (twin-cam. 2.5 liter)
1993 and later M50TU (twin-cam 2.5. liter with VANOS)
535i 1,,130 (single overhea d cam. 3.5 liter)
,
530il5401 1,,160 (V8. 3.0/4.0 liler )
GENERAL