Valve Guide: Testing and Inspection
VALVE, VALVE GUIDE INSPECTION
1. Measure the valve head margin thickness using a vernier caliper.
- If not within the specification, replace the valve.
Valve head standard margin thickness 1.6-2.0 mm {0.063-0.078 in}
2. Measure the length of each valve using the vernier caliper.
- If it is less than the minimum specification, replace the valve.
Valve length (Dimension L)
Standard
IN: 96.80-97.40 mm {3.812-3.834 in}
EX: 96.30-96.90 mm {3.792-3.814 in}
Minimum
IN: 96.58 mm {3.802 in}
EX: 96.08 mm {3.783 in}
3. Measure the stem diameter of each valve using the micrometer. Measurement positions total six and they are in the X and Y directions at the three points (A, B, and C) as shown in the figure.
- If it is less than the minimum specification, replace the valve.
Valve stem diameter
Standard
IN: 5.470-5.485 mm {0.2154-0.2159 in}
EX: 5.465-5.480 mm {0.2152-0.2157 in}
Minimum
IN: 5.424 mm {0.2136 in}
EX: 5.419 mm {0.2134 in}
4. Measure the inner diameter of each valve guide using the caliper gauge. Measurement positions total six and they are in the X and Y directions at the three points (A, B, and C) as shown in the figure.
- If not within the specification, replace the valve guide. (See VALVE GUIDE REPLACEMENT.)
Valve guide standard inner diameter 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.
- If it exceeds the maximum specification, replace the valve or the valve guide, or both. (See VALVE GUIDE REPLACEMENT.)
Clearance between valve stem and guide
Standard
IN: 0.025-0.060 mm {0.0010-0.0023 in}
EX: 0.030-0.065 mm {0.0012-0.0025 in}
Maximum 0.1 mm {0.004 in}
6. Measure the projection height (dimension A) of each valve guide using the vernier caliper.
- If not within the specification, replace the valve guide. (See VALVE GUIDE REPLACEMENT.)
Valve guide standard projection height 12.2-12.8 mm {0.481-0.503 in}