S 500 Sedan (140.051) V8-5.0L (119.980) (1996)
Valve Seat: Service and Repair
Refinish
Refinishing Valve Seats (Part 1 Of 2)
Preparation
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Inspect valve guides. See: Valve Guide/Testing and Inspection
Overview
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Machine valve seats.
Pay attention to operating instructions of tool manufacturer.
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Reference size (T) between valve stem and and bass of camshaft bearing measure, refer to Dimensions. See: Specifications
CAUTION:
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If size "T" is not achieved, no further correct valve clearance compensation exists.
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In this case, the valve seat or the cylinder head should be replaced.
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Maintain dimensions according to table below.
Refinishing Valve Seats (Part 2 Of 2)
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Check leaktightness with valve installed.
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Measure valve seat Width (b).
NOTE: If necessary, correct valve seat width (b) with suitable correction tools (angles a and B).
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Insert valves and measure clearance from valve stem end to base of camshaft bearing (T), refer to Dimensions. See: Specifications
CAUTION: The valves should always be replaced when performing facing work on cylinder head and re setting the valve seats.