1997 BMW 525i ECO

Downloaded from www.Manualslib.com manuals search engine
113-51
Cylinder Head Removal and Installation
< Pull out exhaust camshaft splined shaft to stop.
- Press down on secondary chain tensioner and remove ten-
sioner lock-down tool.
Preload primary chain:
Tighten adjusting screw on
BMW special tool 11 4 220 to
specified torque.
Tightening torque
Primary chain tensioner preload
0.7 Nrn (6 in-lb)
< Preload exhaust camshaft sprrng plate by pressing on im-
pulse wheel while tightening mounting nuts (arrows) finger
tight.
Install BMW special tool 11 6 150 (VANOS setup bracket) to
front of cylinder head timing case. Install nuts (arrows) finger
tight, then tighten down uniformly until special tool is in full
contact with cylinder head.
CAUTION-
Make sure all gasket material is removed from face of cylin-
der head. Clean sealing
face and keep free of oil. If any for-
eign material is present on the sealing
sudace, the camshait
timina will be incorrect.

Downloaded from www.Manualslib.com manuals search engine
Cylinder Head Removal and Installation /
< Clean contact edges of cylinder head face and VANOS unit
and apply a thin coat of permanently elastic Three Bond
1209 8 or equivalent to suriaces.
CAUTION-
Check locating dowel (A) and dowel sleeve (B) at top of
cylinder head for damage or incorrect installation.
Make sure all gasket material is removed from face of
cylinder head. Clean sealing face and keep free of oil.
If any foreign material is present on the sealing surface,
the camshaft timing will be incorrect.
- Install new steel gasket to front of cylinder head and install
VANOS unit.
NOTE -
If VANOS control unit is being replaced, be sure to check and
adjust camshaft timing as described in
11 7 Camshaft Tim-
ing Chain.
- Reinstall engine lifting eye.
Tightening torque
VANOS unit to cylinder head
M6 nut
M7 nut
lo Nm (89 in-lb)
14 Nrn (10 it-lb)
- Reconnect electrical harness connectors to camshaft posi-
tion sensors and VANOS solenoid valves.
4 Insert and tighten down VANOS hydraulic piston set screws
in splined shafts on
intake and exhaust camshafts.
CAUJION-
Set screws have left hand tliread. Tighten counterclockwise.
Tightening torque
Hydraulic piston
to splined shaft 10 Nm (89 in-lb)
< Replace sealing caps inside VANOS unit with short needle
nose pliers.

Downloaded from www.Manualslib.com manuals search engine
11 3-56
I Cvlinder Head Removal and Installation
- Installation of the remaining parts is reverse or removal, not-
ing the following:
- Refill cooling system as described in 170 Radiator and
Cooling System.
Change engine oil and filter as described in
020 Mainte-
nance.
If necessary, adjust accelerator cable.
a Reconnect battery.
CAUTION- To prevent damaging the engine electronic systems, installall
ground wire previously removed, including the ground wires
for the
ionition coils.
Tightening torque Coolant drain
pluq to cylinder bloclc 25 Nm (1 8 ft-lb)
Radiator cooling fan to coolant pump 40 Nm (30 ft-lb) -
Radiator drain screw to radiator 2.5
Nm (22 in-lb)
spark plug to cylinder head 25
Nm (1 8 ft-lb)
CYLINDER MEAD REMOVAL AND
INSTALLATION (M62 ENGINE)
This procedure covers cylinder head removal and installation
for the
M62 V-8 engine. Procedures forthe M62 TU VANOS
engine are not covered in this manual.
Intake manifold, left cylinder head, and right cylinder head re-
moval and installation are written as separate procedures.
The intake manifold must be removed before the cylinder
heads can be removed.
WARNING
-
Due to risk of personal injuv be sure the engine is cold be-
fore beginning the removal procedure.
Cylinder head removal and installation requires multiple spe-
cial service tools. Read the entire procedure before beginning
the repair.
Intake manifold, removal and installation,
M62 engine
- Disconnect negative (-) battery cable.
CAUTION- Prior to disconnecting the
batterj read the baitery discon-
nection cautions
in 001 General Cautions and Warnings.

Downloaded from www.Manualslib.com manuals search engine
This group covers cylinder head and valvetrain service and
repair. Some of the repair procedures described here require
that the cylinder head first be removed as described in
113
Cylinder Head Removal and Installation.
NOTE- For timing chain and
VANOS repair information, see 117
Camshaft Timing Chain.
If it is
determined that the cylinder head will require signif-
icant reconditioning work, a remanufactured cylinder head
may be a good alternative. Remanufactured cylinder
heads are available from an authorized
BMW dealer.
The information given in this repair group is organized ac-
cording to engine code. For engine application information,
see
I00 Engine-General.
For specific repair procedures, refer to the appropriate repair
group:
* 020 Maintenance
100 Engine-General
113 Cylinder Head Removal and Installation
117 Camshafi Timing Chain
= 170 Radiator and Coo!ing System
Special Tools
Special BMW tools are required for most cylinder head ser-
vice described in this repair group. Many of these tools are ex-
pensive and only available through an authorized
BMW
dealer. If the special tools are not available, have the cylinder
head removed and disassembled by an authorized BMW
dealer. Be sure to read each procedure thoroughly before
starting a job to determine which special tools and equipment
will be necessary.
Most of the repairs to a cylinder head require precision
rna-
chine work to specific tolerances. This type of work should be
performed by an authorized BMW repairfacility or an ASE
certified machinist.
71 Torque wrench with flex shaft

Downloaded from www.Manualslib.com manuals search engine
/cylinder Head and Valvetrain
Secondary timing chain tensioner locking pin set (6-cylinder)
- 4 Secondary timing chain tensioner locking pin (V-8)
(Tool No. BMW
11 3 310)
4 Adjustable primary timing chain tensioner tool (V-8)
(Tool No. BMW
11 3 390)
4 Camshaft installation tool (V-8)
(Tool No.
BMW 11 3 430)
4 VANOS compressed air fitting
7 (Tool No. BMW 11 3 450)
Adjustable primary timing chain tensioner tool (6-cylinder) (Tool No. BMW
11 4 220)

Downloaded from www.Manualslib.com manuals search engine
11 6-5
I Cylinder Head and valvetrain1
4 Timing chain tensioner bracket (V-8)
(Tool No. BMW
11 7 380)
CYLINDER HEAD
This section provides the specifications and special recondi-
tioning information necessary to repair the cylinder heads
covered by this manual.
The disassembled cylinder head should be inspected for
warpage and cracks. Check the valve guides and valve seats
for wear before machining a warped head. Always decarbon-
ize and clean the head before inspecting it.
Visually inspect the cylinder head for craclts.
If a cracked cyl-
inder head is suspected and no
craclts are detected through
the visual Inspection, have the head further tested for cracks
by an authorized BMW dealer or an ASE certified machinist.
A cracked cylinder head must be replaced.
NOJE-
When disassembling and inspecting the cylinder head, be
sure to
checlc the camshaft carrier bearing surfaces using a
straight edge for
warpage, and check the lifter bores for wear.
A high-quality straight edge can be used to
checlc for
warpage. A warpage of 0.05 mm (0.002 in.) is acceptable
without machining. A warped cylinder head can be machined
provided no more than 0.3
mm (0.012 in.) of material is re-
moved.
If further machining is required, the head should be
replaced. Removing more than this amount will reduce the
size of the combustion chamber and adversely affect engine
performance. A 0.3 mm
thicker head gasket for machined
heads is available from an authorized BMW parts depart-
ment.

Downloaded from www.Manualslib.com manuals search engine
11 6-6
Cylinder Head and Valvetrain
4 Before machining the head to correct for warpage, measure
the total height
(A) (thickness of the cylinder head). Minimum
height specifications are given in Table a. Cylinder head
height.
NOTE-
6 cylinder and V-8 engines share cylinder head height spec-
ifications.
Table a. Cylinder head height
New Minimum height
(A)
140.0 rnrn (5.512 in.) 139.7 rnrn (5.500 in.)
Valves, leak test
To test the valves for leakage, the cylinder head must be dis-
assembled with camshafts and camshaft carriers removed.
With valve assemblies and spark plugs installed, place the
cylinder head on a workbench with the combustion chamber
facing upward. Fill each combustion chamber with a thin non-
flammable liquid. After fifteen minutes, check the level of the
fluid. If the fluid level in any cylinder drops, that cylinder is not
sealing properly.
Camshaft wear
Camshaft wear is usually caused by insufficient lubrication.
Visually inspect camshaft lobes and journals for wear. Cam-
. ~~ shaft wear specifications are given in Table b. Camshaft
wear specifications.
CA UTIOI\C
If the camshaft is being replaced due to cam lobe wear, it is
recommended that the corresponding lifters should also be
replaced to avoid damaging the new camshaft
Table b. Camshaft wear specifications
6 cylinder engines V-8 engines
Axlal play 0.150-0.330 rnrn 0 200-0 360 rnrn - .-
(0.0060-0 013 in.) (0.008 - 0.014 in ) - - Radlal play 0.020-0.054 rnrn 0.040-0.074 rnrn
(0.0008-0.0021 in.) (0.016 - 0.029 in.)

Downloaded from www.Manualslib.com manuals search engine
Cylinder Head and Valvetrain
< Remove oil baffle cover from above intake camshaft(s)
- Rotate engine at crankshaft vibration damper center bolt in
normal direction of rotation (clockwise) until camshaft lobe of
lifter to be tested points away from the lifter, allowing valve to
be completely closed.
Use a plastic or wooden stick to press down on top of lifter
with approximately 3.5 Nm
(2.25 ft-ib) of force.
If the lifter collapses slightly as though spring loaded, air
may be trapped in the lifter.
NOTE-
Air trapped in hydraulic lifters may result from oil foaming (air
being drawn
in by the oil pump). This may be caused by a
faulty oil pump control valve O-ring; leaking oil pump pickup
gaslcet; or by oil starvation to pump.
Press down on top of lifter for
10 to 15 seconds uslng approx-
lmately 6 to 9 Nm (4.5 to 6.75 ft-lb) of force.
If anv clearance is created between the lifter and the
cam-
shafi lobe, the check valve in the lifter is not closing. Re-
place lifter.
- To replace a hydraulic lifter, remove appropriate camshaft.
Refer to camshaft removal procedures given in Camshaft
and lifter removal and installation.
Once camshaft is removed, withdraw faulty
lifter(s) and re-
place with new
lifter(s). Inspect lifter bores for wear and scor-
ing at arrows.
- Reinstall camshafts. See Camshaft and lifter removal and
installation.