VALVE, VALVE GUIDE INSPECTION
id011000506200
1. Measure the valve head margin thickness using a vernier caliper.
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• If it is less than the standard specification, replace the valve.
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Standard valve head margin thickness
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IN: 1.75—1.95 mm {0.0689—0.0767 in}
EX: 1.95—2.15 mm {0.0768—0.0846 in}
2. Measure the length of the each valve using a vernier caliper.
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• If it is less than the minimum specification, replace the valve.
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Standard valve length
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IN: 120.58—121.18 mm {4.7473—4.7708 in}
EX: 129.92—130.52 mm {5.1150—5.1385 in}
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Minimum valve length
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IN: 120.36 mm {4.7386 in}
EX: 129.70 mm {5.1063 in}
3. Measure the valve stem diameter of each valve using the micrometer. Measurement positions total six and are in the X and Y directions, at three points (A, B, and C) as shown in the figure.
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• If it is less than the minimum specification, replace the valve.
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Standard valve stem diameter
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IN: 5.470—5.485 mm {0.2154—0.2159 in}
EX: 5.465—5.480 mm {0.2152—0.2157 in}
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Minimum valve stem diameter
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IN: 5.424 mm {0.2135 in}
EX: 5.419 mm {0.2133 in}
4. Measure the inner diameter of each valve guide using the caliper gauge. Measurement positions total six and are in the X and Y directions, at three points (A, B, and C) as shown in the figure.
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• If it is not within the specification, replace the valve guide.
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Standard valve guide inner diameter
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IN: 5.510—5.530 mm {0.2170—0.2177 in}
EX: 5.510—5.530 mm {0.2170—0.2177 in}
5. Calculate the clearance between the valve stem and the valve guide by subtracting the inner diameter of the valve guide from the outer diameter of the corresponding valve stem.
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• If it exceeds the maximum specification, replace the valve or valve guide.
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Standard clearance between valve stem and guide
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IN: 0.025—0.060 mm {0.0010—0.0023 in}
EX: 0.030—0.065 mm {0.0012—0.0025 in}
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Maximum clearance between valve stem and guide
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0.10 mm {0.0039 in}
6. Measure the projection height (dimension A) of each valve guide using the vernier caliper.
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• If it is not within the specification, replace the valve guide.
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Standard valve guide projection height
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IN: 16.4—17.0 mm {0.646—0.669 in}
EX: 16.4—17.0 mm {0.646—0.669 in}
