BMW 3 Series Service Manual (E39)
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Cylinder Head and valvetrain1
4 Timing chain tensioner bracket (V-8) (Tool No. BMW 11 7 380)
CYLINDERHEAD
This section provides the specifications and special reconditioning 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 decarbonize and clean the head before inspecting it.
Visually inspect the cylinder head for craclts. If a cracked cylinder 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, andcheck 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 removed. 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 department.
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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 specifications.
Table a. Cylinder head height |
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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 disassembled 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 nonflammable 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. Camshaft wear specifications are given in Table b. Camshaft wear specifications.
CAUTIOI\C
If the camshaft is being replaceddue to cam lobe wear, it is recommended that the correspondinglifters should also be replaced to avoid damaging the new camshaft
Table b. Camshaft wear specifications |
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6 cylinder engines |
V-8 engines |
Axlal play |
0.150-0.330 rnrn |
0 200-0 360 rnrn |
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(0.0060-0 013 in.) |
(0.008 - 0.014 in ) |
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Radlal play |
0.020-0.054 rnrn |
0.040-0.074 rnrn |
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(0.0008-0.0021 in.) |
(0.016 - 0.029 in.) |
Cylinder Head and valvetrain1
Hydraulic lifters, checking and replacing
Self-adjusting hydraulic lifters (A) keep the valve clearances within a limited working range. Hydraulic lifters are sealed units and require no maintenance. Section view of camshaft ( 6 )and valve with conical valve spring (C) shown.
Under some circumstances, such as a cold start, the cam followers may emit noise. Hydrauliclifter noise is usually a highpitched tapping or chattering noise. In most instances,this is considered normal as long as the noise goes away in a few minutes (maximum20 minutes). If the noise does not go away, either the lifter is faulty or the oil pressureto the lifter is low. Hydraulic lifter replacement requires that the camshaft first be removed.
NOTE-
Before checking hydraulic lifters, male sure engine oil is fresh andat the proper level. Stickylifters can be the result of sludge build up in the cylinder head and lifters.
-Run engine until it reaches normal operating temperature. Shut off engine.
-Working inside luggage compartment, disconnect negative battery cable.
CAUTION-
Prior to disconnecting battery cable, read the baltery dlsconnectioncautionsgivenIn 001 General Cautions and Warnings.
Disconnecting the battery may erase fault code(s) storedin controlmodule memory Check for fault codes
4 Remove left and right interior ventilation duct (left side shown):
Release plastic locking tab (A) or release loclting tabs on top of duct (later models).
Rotate duct counterclockwiseto unloclt from bulitheadand remove (arrow).
Cylinder Head and Valvetrain
-&cylinder models: remove plastic top covers:
- Pry out caps (arrows). Remove fasteners and covers.
4 V-8 models: remove plastic top covers:
Press down on locking pins (arrows) to release locks and remove top cover.
Pry out caps (A) from covers.
Remove fasteners and covers.
4 Lift metal latch on coil harness connectors and disconnect harness connectors from coils. 6-cylinder shown, V-8 similar.
-Remove coil grounding straps.
NOTE-
Make note of ground wire at mounting studs arrangement during removal.
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Cvlinder Head and valvetrain1
4 Remove ignition coils and spark plugs.
V-8 models: remove mounting nuts (arrows) from wiring harness ducting.
<V-8 models: disconnect fuel injector electrical connectors from injectors:
Pry one corner of wire loclc clip (arrow) on first injector.
Repeat for all injectors.
Lift wire ducts off and set aside.
-V-8 models: disconnect battery jump start post terminal from left cylinder head cover.
-6-cylinder models: remove oil filler cap and unclip vent connection from cylinder head cover.
-Remove cylinder head cover mounting fasteners and remove cylinder head cover(~).
NOTE-
The cylinder head cover mounting bolt insulators and gasIcets should be reinstalled in their original locations. Make note of their arrangement during removal.
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 inhydraulic lifters mayresult from oilfoaming (air being drawn in by the oil pump). This may be caused by a faulty oilpump 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 approxlmately 6 to 9 Nm (4.5 to 6.75 ft-lb) of force.
If anv clearance is created between the lifter and the camshafi lobe, the check valve in the lifter is not closing. Replace lifter.
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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 replace with new lifter(s). Inspect lifter bores for wear and scoring at arrows.
Reinstall camshafts. See Camshaft and lifter removal and installation.
Cylinder Head and Valvetrain
4 Install intake camshaft oil baffle cover and cylinder head cover:
=Checlc for correct seating of half-moon seals (A) in back of cylinder head cover.
Use a small amount of Three Bond 1209 @or equivalent sealant at corners (B)of half-moon cutouts and corners in front of cylinder head at joint to timing chain cover.
Align cover at front and rear, then alternatively tighten fasteners from inside to outside.
Tightening torque |
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Sparic plug to cylinder head |
25 Nm (18 it-lb) |
Ignition coils to cylinder head |
10 Nrn (7.5 ft-lb) |
Cylinder head cover to cylinder iiead |
10 Nrn (89 in-lb) |
fM6 screws) |
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CAMSHAFTAND LIFTERREMOVAL
AND ~NSTALLATION
The camshafts can be removed with the cylinder heads mounted on the engine (in the car).
On 6-cylinder engines there are two different procedures given, depending on whether the engine is equipped with single VANOS (M52 engine) or double VANOS (M52TU or M54 engine).
For V-8 engines, camshaft removal and installation procedures are only included for the non-VANOS (M62) engine. Camshaft removal and installation for the VANOS eq;ipped V-8 (M62TU) is not covered in this manual.
Special BMW service tools should always be used to remove and install the camshafts. Removal of the camshafts without the special tools can result in cylinder headdamage and camshaft breakage.
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Cylinder Head and Valvetrain |
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Camshaft and lifter removal and installation |
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(M52 engine) |
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Camshafts and lifters, removing (M52engine) |
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WARNING- |
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Theprocess of evenly loosening the camshaftbearing cap |
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nuts is NOT an acceptable method of removing the cam- |
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shafts. Special tools should always be used to remove the |
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camshafts. Be sure to read the procedure tlirough before |
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starting ajob. |
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I Allow engine to cool before beginning this procedure. / |
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Disconnect negative (-) cable from battery. |
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CAUTION- |
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Prior to disconnecting the batfew read the battery discon- |
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nection cautions given in 001 General Cautions and |
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Warnings. |
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Remove VANOS control unit from cylinder head. See 117 |
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Camshaft Timing Chain. |
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I 4 Remove loosened bolts (arrows)from front of exhaust |
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sprocket |
nuts (arrows)from intake camshaft
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Cylinder Head and Valvetrain |
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I < Remove outer thrust washer, sprinq plate, and inner thrust |
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washer. |
4 Remove both camshait sprockets with secondary timing chain.
NOTE-
Keep chain andsprockets togetheras anassembly for easier installation.
<Remove thrust washer studs (arrows) and remove thrust washer.
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ICylinder Head and Valvetrain
4 Remove sensor gear (arrow).
Remove secondary timing chain tensioner retaining bolts (arrows) and remove tensioner.
Remove timing chain guide reta~ningbolts (arrows) and remove guide.