VALVE, VALVE GUIDE INSPECTION

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1. Measure the valve head margin thickness using a vernier caliper.

  • If it is less than the specification, replace the valve.

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  Margin thickness

  IN: 1.85 mm {0.0728 in}
  EX: 2.05 mm {0.0807 in}

2. Measure the length of each valve. Replace the valve if necessary.

  • If it is less than the specification, replace the valve.

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  Standard length L

  IN: 102.99—103.79 mm {4.055—4.086 in}
  EX: 104.25—105.05 mm {4.105—4.135 in}

  Minimum length L

  IN: 102.99 mm {4.055 in}
  EX: 104.25 mm {4.105 in}

3. Measure the stem diameter of each valve in X and Y directions at the three points (A, B, and C) as indicated in the figure.

  • If it exceeds the specification, replace the valve.

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  Standard diameter

  IN: 5.470—5.485 mm {0.2154—0.2159 in}
  EX: 5.465—5.480 mm {0.2152—0.2157 in}

  Minimum diameter

  IN: 5.470 mm {0.2154 in}
  EX: 5.465 mm {0.2152 in}

4. Measure the inner diameter of each valve guide in X and Y directions at the three points (A, B, and C) as indicated in the figure.

  • If not as specified, replace the valve guide.

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  Standard Inner diameter

  5.509—5.539 mm {0.2169—0.2180 in}

5. Calculate the valve stem to guide clearance by subtracting the outer diameter of the valve stem from the inner diameter of the corresponding valve guide.

  • If it exceeds the specification, replace the valve and/or the valve guide.

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  Standard clearance:

  IN: 0.024—0.069 mm {0.0009—0.0027 in}
  EX: 0.029—0.074 mm {0.0012—0.0029 in}

  Maximum clearance:

  0.10 mm {0.004 in}

6. Measure the protrusion height (dimension A) of each valve guide without lower valve spring seal using the vernier caliper.

  • If not within the specification, replace the valve guide.

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  Standard diameter:

  12.2—12.8 mm {0.481—0.503 in}