Valve, Valve Guide Inspection
- Measure the valve head margin thickness using a vernier caliper.
- If it is less than the specification, replace the valve.
Minimum valve head margin thickness
IN: 1.65 mm {0.0650 in}
EX: 1.85 mm {0.0728 in}
- Measure the length of each valve. Replace the valve if necessary.
- If it is less than the specification, replace the valve.
Standard valve length (Dimension L)
IN: 102.99-103.79 mm {4.0548-4.0862 in}
EX: 104.25-105.05 mm {4.1044-4.1358 in}
Minimum valve length (Dimension L)
IN: 102.99 mm {4.0548 in}
EX: 104.25 mm {4.1044 in}
- 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.
Standard valve stem diameter
IN: 5.470-5.485 mm {0.2154-0.2159 in}
EX: 5.465-5.480 mm {0.2152-0.2157 in}
Minimum valve stem diameter
IN: 5.470 mm {0.2154 in}
EX: 5.465 mm {0.2152 in}
- 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.
Standard valve guide inner diameter
5.509-5.539 mm {0.2169-0.2180 in}
- 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.
Standard clearance between valve stem and guide
IN: 0.024-0.069 mm {0.0010-0.0027 in}
EX: 0.029-0.074 mm {0.0012-0.0029 in}
Maximum clearance between valve stem and guide
0.10 mm {0.004 in}
- Measure the protrusion height (dimension A) of each valve guide without lower valve spring seat using the vernier caliper.
- If not within the specification, replace the valve guide.
Standard valve guide projection height
12.2-12.8 mm {0.481-0.503 in}