Valve Train, Servicing
Valve train, servicing
Notes:
^ Cylinder heads which have cracks between the valve seats or between valve seat inserts and the spark plug thread can continue to be be used without reducing service life provided the cracks do not exceed a maximum of 0.3 mm in width, or when no more than the first four spark plug threads are cracked.
^ After installing new hydraulic lifters, do NOT start the engine for approx. 30 minutes or the valves will strike the pistons. After 30 minutes manually turn the crankshaft two rotations before starting.
1- 100 Nm (74 ft. lbs.)
- Use 3415 counter-hold to loosen and tighten
2- Camshaft sprocket
3- oil seal
4- Woodruff key
- Ensure tight fit
5- 20 Nm (15 ft. lbs.)
6- Bearing cap
^ Installation position see Fig. 3
^ Installation sequence Refer to Camshaft, removing and installing.
- Lightly coat bearing cap 1 contact surfaces with D 454300 A2 sealant
7- Camshaft
^ Axial clearance, checking see Fig. 2
^ Radial clearance, checking with plastigage:
- Wear limit: 0.1 mm
^ Run-out: max. 0.01 mm
^ Identification and valve timing see Fig. 5
8- Hydraulic lifter
- Do not interchange
^ with hydraulic clearance compensation
- Store with cam contact surface facing downwards
- Check camshaft axial clearance before installing see Fig. 2
- Oil contact surfaces
9- Keepers
10- Valve spring retainer, upper
11- Valve spring
^ Removing and installing:
- Cylinder head removed: use 2037
12- Valve stem seal
13- Valve guide
^ Service version with collar
14- Cylinder head
15- intake and exhaust valves
- Do not rework! Only lapping is permitted.
Fig. 1 Cylinder head sealing surface, reworking
^ Cylinder head reworking dimension: a = 132.6 mm min.
Note:
When the sealing surface has been reworked, the valves must be set deeper by the same amount (rework valve seat inserts), otherwise the valves will contact the pistons. Ensure that the minimum permissible dimension is maintained while doing this.
Fig. 2 Camshaft axial clearance, checking
Special tools and Equipment
^ VW 387 Universal dial gauge bracket
^ Dial Indicator
Note:
Check with hydraulic lifters removed and with first and last bearing caps installed.
^ Wear limit: max. 0.15 mm
Fig. 3 Camshaft bearing caps, installed position
Note the offset. Before installing the camshaft - install the bearing caps to determine the correct installed position.
Fig. 4 Valves, dimensions
Note:
- Do NOT re-work the valves! Only lapping is permitted.
Engine Code AEG
Engine Code AVH, AZG
Fig.5 Camshaft identification, valve timing
Identification
^ Cam base diameter: a = 34 mm (diameter)
^ Identification by stamped numbers and letters between intake and exhaust lobes:
Valve timing at 1 mm valve lift
Valve seats, reworking
Special tools and Equipment
^ Depth gauge
^ Valve seat refacing tool
Notes:
^ When repairing engines with leaking valves, it is not always sufficient to reface or replace valve seats and valves. It is also necessary to check the valve guides for wear This is particularly important on high mileage engines.
^ The valve seats should only be reworked enough to produce a symmetrical seating pattern. The Maximum permissible reworking dimension must be calculated before reworking begins. If this dimension is exceeded, proper function of the hydraulic lifters can no longer be guaranteed and the cylinder head must be replaced,
Maximum permissible reworking dimension, calculating
- Insert valve and press firmly against seat.
Note:
If the valve is to be replaced as part of a repair use the new valve for the calculation.
- Measure distance -a- between end of valve stem and upper edge of cylinder head.
- Calculate Max. permissible reworking dimension from measured distance -a- MINUS the minimum dimension.
- Minimum dimension:
- Intake valve 33.8 mm
- Exhaust valve 34.1 mm
Measured distance MINUS the minimum dimension = Maximum permissible reworking dimension.
Example:
Note:
Exhaust valve seat inserts also have an additional internal constriction. When reworking, ensure that the radius of the constriction is not damaged.
Intake valve seat, reworking
Exhaust valve seat, reworking
Note:
- Exhaust valve seat inserts also have an additional internal construction. When reworking, ensure that the reduction radius is not damaged.
Camshaft oil seal, replacing
Special tools and Equipment
- 10-203 Oil Seal Driver
- 2085 Seal puller - general usage
- 3415 Counter support
- VAG 1331 Torque wrench 5 to 50 Nm (3.7 to 37 ft lb), or equivalent.
- VAG 1332 Torque wrench 40 to 200 Nm (30 to 148 ft lb), or equivalent.
Only PTFE Oil Seals
Special Tools and Equipment
- 2085 Seal puller - general usage
- 3415 Counter support
- T10071 puller
- VAG 1331 Torque wrench 5 to 50 Nm (3.7 to 37 ft lb), or equivalent.
- VAG 1332 Torque wrench 40 to 200 Nm (30 to 148 ft lb), or equivalent.
Removing
All Oil Seals
- Remove camshaft belt guard - upper section.
- Set camshaft sprocket to cyl. 1 TDC by turning crankshaft.
^ Mark on camshaft sprocket must align with arrow on cylinder head cover.
- Release tensioning roller and take toothed belt off camshaft sprocket.
- Turn crankshaft back slightly.
- Remove camshaft sprocket using 3415 counter-hold. (Remove bolts from holes -arrows- before using tool)..
- Remove woodruff key from camshaft.
- Fully screw camshaft sprocket securing bolt (with washer) into camshaft.
- Unscrew inner part of 2085 oil seal extractor two turns (approx. 3 mm) out of the outer section and lock in position using knurled screw.
- Lubricate threaded head of oil seal extractor, place in position and while exerting firm pressure, screw it into the oil seal as far as possible.
- Loosen knurled screw and turn inner section of extractor against camshaft until oil seal has been extracted.
- Clamp flats of oil seal extractor in vice.
- Remove oil seal with pliers.
Installing
Conditions
- Pistons must not be positioned at TDC.
Note:
- Gradual introduction of PTFE oil seal (identifying characteristics: no annular spring, sealing lip wider). The sealing lip of this oil ring MUST NOT be oiled or lubricated. A plain encased seal of older construction (with annular spring) may be replaced with a PTFE oil seal, but not vice versa.
Only PTFE Oil Seal
- Position oil seal with guide sleeve TI 0071/1 and press in to stop using press sleeve 110071 and bolt T1007112.
Only Oil Seals with Annular Spring
- Lightly oil sealing lip of oil seal. (Only Oil Seals with Annular Spring)
- Start oil seal with sleeve from 10-203 and press in, up to stop using 10-203.
Continuation
- Insert woodruff key in camshaft.
- Install camshaft sprocket and tighten by counterholding sprocket using 3415 counterhold. (Remove bolts from holes -arrows- before using tool).
- Tightening torque: 100 Nm (74 ft lb)
Note:
- When the camshaft is turned, the crankshaft must not be at TDC. If so, there is a danger of damage to the valves or piston crowns.
- The rest of the assembly is basically a reverse of the disassembly sequence.
- Install toothed belt and adjust timing.
Camshaft, removing and installing
Special tools and Equipment
^ 3415 Counter Support
^ VAG 1331 Torque Wrench 5 to 50 Nm (3.7 to 37 ft. lbs.)
^ VAG 1332 Torque Wrench 40 to 200 Nm (30 to 148 ft. lbs.)
^ AMV 174 004 01 Sealant
Removing
- Remove intake manifold upper part:
- Note:
- Seal the open portions of the lower intake manifold against dirt etc. with clean shop rags.
- Remove camshaft drive belt guard upper section.
- Set camshaft sprocket to cyl. 1 TDC by turning the crankshaft.
^ Mark on camshaft sprocket must align with arrow on cylinder head cover.
- Release tensioning roller and take toothed belt off camshaft sprocket.
- Turn crankshaft back slightly.
- Remove camshaft sprocket by using 3415 counter-hold.(Remove bolts from holes -arrows- before using tool).
- Remove woodruff key from camshaft.
- Remove cylinder head cover.
- First remove bearing caps 5, 1 and 3, then loosen bearing caps 2 and 4 alternately and diagonally.
Installing
Conditions
^ Pistons must not be positioned at TDC.
Note:
^ When installing the camshaft No. 1 cylinder cams must point upwards.
^ When installing the bearing cap note the offset. Before installing camshaft fit bearing caps and determine installation position.
- Oil camshaft contact surfaces.
- Install camshaft.
- Tighten bearing caps 2 and 4 alternately and diagonally
^ Tightening torque: 20 Nm (15 ft. lbs.)
- Lightly coat bearing cap 1 contact surfaces with sealant AMV 174 004 01.
- Install bearing caps 3, 1 and 5 and tighten
^ Tightening torque: 20 Nm (15 ft. lbs.)
- Insert woodruff key in camshaft.
- Install camshaft sprocket and tighten by counterholding sprocket using 3415 counter-hold. (Remove bolts from holes -arrows- before using tool).
^ Tightening torque: 100 Nm (74 ft. lbs.)
Note:
- When camshaft is turned, the crankshaft must not be at TDC. If so, there is a danger of damage to the valves or piston crowns.
^ The rest of assembly is basically a reverse of the disassembly sequence.
^ See Installing toothed belt and adjusting timing.
^ When new lifters have been installed the engine must not be started for about 30 minutes. Hydraulic compensation elements must settle (otherwise valves will strike pistons).
Hydraulic lifters, checking
Special tools and Equipment
^ Feeler gauge
^ Wooden or plastic wedge
Note:
^ Replace faulty lifter complete (cannot be adjusted or repaired).
^ Irregular valve noises when starting the engine is normal.
Test sequence
- Start engine and run until radiator fan has switched on once.
- Increase engine speed to about 2500 rpm for approx. 2 min.
If lifter(s) are still noisy, locate faulty lifter(s) as follows:
- Remove the intake manifold upper part:
Note
- Seal the open portions of the lower intake manifold against dirt etc. with clean shop rags.
- Remove cylinder head cover.
- Rotate crankshaft clockwise, until cam of lifter to be checked is pointing upwards.
- Determine play between cam and lifter.
- If play is in excess of 0.2 mm, replace lifter. If play is less than 0.1 mm or no play proceed with checks as follows:
- Push hydraulic lifter down lightly with a wooden or plastic wedge. If when pushed down a 0.2 mm thick feeler gauge can be inserted between the camshaft and lifter, replace that lifter.
Note:
DO NOT start the engine for approx. 30 minutes after installing new lifters. Hydraulic compensation elements in the lifters must settle otherwise the valves will strike the pistons.
Valve guides, checking
Special tools and Equipment
^ VW 387 Universal dial gauge bracket
^ Dial gauge
Test sequence
- Insert new valve into guide until end of valve stem is flush with end of guide. Due to slight difference in stem diameters, ensure that the intake valve is only used in the intake guide and an exhaust valve only in the exhaust guide.
- Measure "rocking dimension".
- Wear limit:
- Intake valve guide 1.0 mm
- Exhaust valve guide 1.3 mm
Valve guides, removing and installing
Special tools and Equipment
^ 3120 Reamer and cutting fluid
^ 3121 Drift
Removing
- Clean and check cylinder head.
- Cylinder heads in which the valve seats can no longer be reworked, or cylinder heads which have already been machined to the minimum dimension, should not have the valve guides replaced. The permissible minimum dimension must be maintained.
- Press out worn valve guides with 3121 from the camshaft side (valve guides with shoulder - repair version - from combustion chamber side).
Installing
- Press in new guides, moistened with oil, from camshaft side onto shoulder in cold cylinder head using drift 3121.
Note:
- Once the guide shoulder makes contact, DO NOT allow the pressure to exceed 2000 psi otherwise the guide shoulder could break off.
- Ream out guides with 3120 hand reamer using plenty of cutting fluid.
- Rework valve seats. Refer to Valve seats, reworking.
Valve stem seals, replacing
Special tools and Equipment
^ VAG 1331 Torque wrench 5 to 50 Nm (3.7 to 37 ft. lbs.) or equivalent
^ VW 541/1A Valve lever
^ VW 541/5 Thrust piece
^ VW 653/3 Pressure hose
^ 2036 Assembly fixture
^ 3047A Slide Hammer
^ 3122 B Spark plug Removal Tool
^ 3129 Seal Driver
- T10029 Spark Plug Connector Tool
Removing
With cylinder head installed
- Remove camshaft. Refer to Camshaft, removing and installing.
- Remove hydraulic lifters and place them with contact surfaces facing downwards.
Note:
Ensure that the lifters are not interchanged during this step.
- Remove spark plug connectors using T10029 tool. Place spark plug wires aside:
- Remove spark plugs using 3122 tool.
- Set piston of appropriate cylinder to "Bottom Dead Center".
- Fit assembly tool 2036 and adjust mountings to height of studs.
- Screw pressure hose VW 653/3 into the spark plug thread.
- Connect pressure hose to an air system with at least 6 bar (87 psi).
- Remove valve springs with VW 541/1A lever and VW 541/5 press piece.
Note:
- Tight keepers can be loosened by lightly tapping on the lever
- Pull off valve stem seals using tool 3047A.
Installing
- Place plastic sleeve -A- (supplied with replacement part) on the appropriate valve stem.
^ This will prevent the new valve stem seal -B- from being damaged.
- Insert new valve stem seal in 3129 installation tool.
- Oil valve stem seal sealing lip and press carefully onto the valve guide.
- Install camshaft.