PRE-RELEASE
Valve gear
| Valve gear |
(Cylinder head removed, fitted in fixture, part no. 83 93 795)
| To remove |
| Important | ||
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The cylindrical surfaces round the valve springs are sealing surfaces for the tappets and must not be scratched or scored. Therefore, fit protective collars, part no. 83 93 746, round the tappet cylinders. |
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| 1. |
Remove the camshaft bearing caps. It is important to finish removal of the bearing caps with the one where the tappets are under load. Lift out the camshafts.
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| 2. |
Remove the tappets and place them in the valve stand, part no. 83 93 787.
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| 3. |
Fit the protective collars, part no. 83 93 746.
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| 4. |
Press down the valve heads with the valve spring compressor, part no. 83 95 246, and remove the collets.
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| 5. |
Lift out the spring discs and valve spring. Do not forget the washer.
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| 6. |
Remove the valves and place them in the valve stand, part no. 83 93 787.
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| To fit |
| Important | ||
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Defective valve stem seals must be replaced and the sealing surfaces with bearings lubricated before the valves are fitted. Make sure that the cylinder head is mounted in the fixture, part no. 83 93 795, so that the valves are not bent when the camshafts are tightened. |
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| 1. |
Fit the valves and springs.
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| 2. |
Use valve spring compressor, part no. 83 95 246, to fit the spring discs and collets.
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| 3. |
Place the clearance gauge, part no. 83 93 753, across two of the camshaft bearing seats with the depth gauge against the end of the valve stem.
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| 4. |
Check that the maximum gauge depth of 20.5 mm actually reaches down to the end of the valve stem (noticed by the valve clearance gauge not bottoming against the bearing seat closest to the depth gauge).
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| 5. |
Then, check that the minimum gauge depth of 19.5 mm does not reach down to the end of the valve stem. The correct valve clearance is between the minimum and maximum gauge depths. If the clearance is less than the minimum, the valve stem must be shortened and if it is greater than the maximum, the valve seat must be reground.
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| 6. |
Remove the protective sleeves and fit the valve tappets.
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| 7. |
Fit the camshafts and bearing caps, start where cams are pointing down and acting on the tappets. The bearing caps are marked 1-5 for the intake side and 6-10 for the exhaust side.
Tightening torque: 15 Nm (11 lbf ft)
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| 8. |
Line up the marks on the camshafts with their timing marks.
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