Note | If there is not achieved a good seating pattern by lapping the valve seats, the valve seats must be reworked |
| Special tools and workshop equipment required |
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| Valve seat re-facing tool |
Note | t
| When repairing engines with leaking valves, it is not sufficient to reface the valve seats and renew the valves. The valve guides must also be checked for wear. This is particularly important on high mileage engines → Chapter. |
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| The valve seats should only be reworked just enough to produce a good seating pattern. |
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| The maximum permissible machining dimension must be calculated before starting work. |
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| If the reworking dimension is exceeded, hydraulic valve compensation can no longer be guaranteed and the cylinder head should be renewed. |
| Maximum permissible reworking dimension: calculation |
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| Insert valve and press firmly against valve seat. |
Note | If the valve is to be renewed as part of a repair, use a new valve for the calculation. |
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