Replacing Valve-Stem Seals
Replacing valve-stem seals
Preliminary work
Information
* The valve-stem seals can be replaced when installed.
* Depending on the tool setup, peripheral components at the sides, such as plenum panels or servo oil reservoirs, may first have to be removed
* The tool can be adjusted to all M6 or M8 studs or internal threads (tool details below).
* The angle of the assembly bar lever can be adjusted according to space requirements.
1. Remove camshafts.
2. Take hydraulic tappets out of the cylinder head and lay them on a clean surface, arranged according to cylinders and valves. Do not interchange components.
Information
Component overview
In the Turbo, the exhaust valve is fitted with internal and external valve springs (set of valve springs) and adapted concave washers. The exhaust valve in the turbo engine has the same outer dimensions as the exhaust valve of the naturally aspirated engine. However, because of the sodium filling, the exhaust valve in the turbo engine is lighter and the shank over the shank entries is longer. For further details, please see Figures and Table entitled "Valve dimensions".
Valves (Figure, turbo cylinder bank 5 to 8)
1 - Intake valve (identical in the naturally aspirated and turbo engines)
2 - Valve-seat ring intake
3 - Valve guide
4 - Lower valve-spring plate intake
5 - Valve stem seal
6 - Set of valve springs, intake (identical in the naturally aspirated and turbo engines)
7 - Upper valve-spring plate intake
8 - Valve collet
9 - Upper valve-spring plate outlet (different in the naturally aspirated and turbo engines)
10 - Set of valve springs (turbo outlet); valve spring (naturally aspirated engine outlet)
11 - Lower valve-spring plate outlet (different in the naturally aspirated and turbo engines)
12 - Valve-seat ring outlet
13 - Exhaust valve (different in the naturally aspirated and turbo engines)
Distinguishing feature of exhaust valve on naturally aspirated and turbo engine
Difference between exhaust valve on naturally aspirated and turbo engine
1 - Exhaust valve - naturally aspirated engine
2 - Exhaust valve - turbo engine
3 - Difference in shank length over shank entries
Special tools
Special tools for valve
1 - Puller 3364 => only used to remove valve-stem seals.
2 - Assembly driver 9606/1 => only used to remove valve-stem seals.
3 - Universal assembly bar with universal assembly driver Tool for fitting/removing valve keys Nr.54 Pos.1
4 - Hooking piece (fitting hook) with holder (several possible)
5 - Plastic guide for inlet and outlet valve 31mm fastening screw Nr.54 Pos.1A and 28mm fastening screw Nr.54 Pos.1B
6 - Assembly fixture for valve keys
7 - Assembly cartridge for valve keys
8 - Assembly bar (hook) with adjustable lever
Removing valve-stem seal
Removing valve-stem seals
Information
When required, all valve-stem seals on both cylinder rows must be replaced.
Information
* Before switching to another cylinder, the cylinder must be positioned at the bottom dead center and supplied with compressed air (see above).
Information
* Position the pistons of the relevant cylinder at the bottom dead center.
* Each piston is pressed downwards as pressure builds up in the cylinder.
1. Position the pistons of the relevant cylinder at the bottom dead center. To do this, guide the timing chain carefully when turning the crankshaft.
2. Screw in compressed-air hose from the valve key assembly/disassembly tool for the Cayenne NR.54-1 tool set (or similar) in the relevant spark plug bore so that it is tightly sealed. Apply compressed air constantly to cylinder (at least 6 bar overpressure). This builds up pressure in the cylinder so that the valve does not fall into the cylinder while you are working. Replace all four valve-stem seals for a cylinder and refit valve keys. Only then fit compressed-air hose on the next cylinder and apply compressed air constantly.
3. Fit and set the tool on the cylinder head
3.1. Screw -1- a holder with the appropriate thread into its matching thread on the cylinder head. The hooking piece -2- is pre-fitted in the holder.
Fit the hook
3.2. Insert the appropriate plastic guide -1- in place of the tappet.
Insert plastic guide
3.3. Insert assembly cartridge -1- for the valve keys into the plastic guide.
Insert assembly cartridge
3.4. Hook the lever (assembly bar) -1- into the hook and place correctly onto the assembly cartridge. Make sure that the tool and equipment can be effective directly.
Correctly fit the tool
4. Remove the valve keys
4.1. Press the assembly cartridge with the lever (assembly bar) against the force of the valve-spring and keep pressed. The knurled screw of the assembly cartridge pushes forward -1-.
Press down the tool
Press down the lever and knurled screw
Information
The mechanic must practice for use of the assembly cartridge to be effective. Some repetitions must be made to ensure that the valve keys are correctly held in place.
4.2. Turn the knurled screw back and forth -1- until the valve keys snap into place and are held there -2- in the assembly cartridge. The knurled screw retracts.
Turn the knurled screw back and forth
4.3. Remove the assembly cartridge and check correct position of both valve keys -1-.
Valve keys in assembly cartridge
4.4. Pull out the knurled screw from the assembly cartridge -1- and knock out the valve keys -2-.
Remove the valve keys
5. Remove valve springs, spring plate and valve keys from the cylinder head.
6. Withdraw sliding sleeve of puller 3364. When positioning the puller 3364 on the fitted valve-stem seal, ensure that the metal edge of the valve-stem seal is positioned behind the corresponding metal edge of the puller. -1-.
Valve-stem seal before puller
Valve-stem seal in puller
7. When engaging the puller 3364, push sliding sleeve down and close tool. -arrow-
Closed puller
8. Remove valve-stem seal by activating the negative (slide) hammer. -arrow-. Repeat procedure for valves on pressurized cylinder (reposition tool accordingly).
Removing valve-stem seal
Installing valve-stem seal
Installing valve-stem seals
Information
* Position the pistons of the relevant cylinder at the bottom dead center.
* Each piston is pressed downwards as pressure builds up in the cylinder.
Information
* Before switching to another cylinder, the cylinder must be positioned at the bottom dead center and supplied with compressed air (see above).
Information
When required, all valve-stem seals on both cylinder rows must be replaced.
Information
Protective caps must be ordered as separate spare parts. They are reusable. They are used to protect the valve-stem seal so that it is not damaged at the valve stem end.
1. Prepare valve-stem seal -1-, protective cap -3- and assembly driver 9606/1 -2-.
Valve-stem seal with tool
2. Push protective cap onto valve stem end.
Protective cap
3. Oil valve stem, protective cap and valve-stem seal. Push valve-stem seal with sealing lip upwards -1- over the protective cap -2- onto the valve stem. Remove protective cap.
Valve-stem seal pushed over protective cap and valve
4. Guide the assembly driver 9606/1 over the valve stem and fit the valve-stem seal by hand or by tapping it lightly using the rubber hammer as far as it will go. -arrow-
Pushing on valve-stem seal
5. Fit valve springs, concave washer and valve keys. To do this, place valve springs (there are two in the exhaust valve in the turbo engine) on the bottom concave washer. Place top concave washer in position.
Information
The mechanic must practice for use of the assembly cartridge to be effective. Some repetitions must be made to ensure that the valve keys are correctly held in place.
6. Insert valve keys into the assembly cartridge.
6.1. Press the spring washer of the assembly fixture downwards -1- and insert the valve key -2- with the narrow end pointing downwards.
Valve key in assembly fixture
6.2. Ensure that the valve keys fit symmetrically and are inserted as far as they will go in the tool. The spring washer automatically locks the valve keys in place.
6.3. Place the assembly cartridge -2- onto the center of the assembly fixture. Observe installation position of the valve keys -1-.
Fit the assembly cartridge
6.4. Press the assembly cartridge against the spring force onto the assembly fixture. The knurled screw moves forward. When doing so, turn the knurled screw back and forth until the valve keys snap into place. Repeat as required.
Assembly cartridge accepts the valve keys
6.5. Make sure the valve keys are held symmetrically in place in the assembly cartridge -1-.
Valve keys inserted
7. Place the valve key assembly cartridge onto the cylinder head (same as removal of valve) and position it on the top spring plate.
8. Press the assembly cartridge with the lever (assembly bar) against the force of the valve-spring and keep pressed. The knurled screw moves forward. When doing so, turn the knurled screw back and forth until the valve keys snap into place. Repeat as required.
Install valve keys
9. When installing the valve keys, check their correct positioning.
10. Replace all four valve-stem seals for a cylinder and refit valve keys. Only then fit compressed-air hose on the next cylinder and apply compressed air constantly.
Subsequent work
1. Fit hydraulic tappets. Do not interchange components.
2. Install camshafts.