Valve Guide: Testing and Inspection

VALVE, VALVE GUIDE INSPECTION





1. 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)

2. 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)

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

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





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.

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)





6. 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)