Valve, Valve Guide Inspection

WARNING: This page does not describe the selected car, but rather 22 other vehicles, including the 2009 Mazda B2300, 2009 Mazda 5, 2008 Mazda Tribute, 2008 Mazda B2300, and 2008 Mazda 5. However, it is still accessible from the selected car via links, so may be relevant.

Measure the valve head margin thickness of each valve.
- If it is less than the specification, replace the valve.
Margin Thickness
1. IN: 1.62 mm {0.0637 in}
2. EX: 1.82 mm {0.0716 in}
  
  Fig 1: Measuring Valve Head Margin Thickness
  Courtesy of MAZDA MOTORS CORP.
Measure the length of each valve. Replace the valve if necessary.
- If it is less than the specification, replace the valve.
Standard Length L
1. IN: 102.99-103.79 mm {4.055-4.086 in}
2. EX: 104.25-105.05 mm {4.105-4.135 in}
Minimum Length L
1. IN: 102.99 mm {4.055 in}
2. EX: 104.25 mm {4.104 in}
  
  Fig 2: Measuring Valve Length
  Courtesy of MAZDA MOTORS CORP.
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 Diameter
1. IN: 5.470-5.485 mm {0.2154-0.2159 in}
2. EX: 5.465-5.480 mm {0.2152-0.2157 in}
Minimum Diameter
1. IN: 5.440 mm {0.2142 in}
2. EX: 5.435 mm {0.2140 in}
  
  Fig 3: Measuring Valve Stem Diameter
  Courtesy of MAZDA MOTORS CORP.
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 Inner Diameter
1. 5.509-5.539 mm {0.2169-0.2180 in}
  
  Fig 4: Measuring Valve Inner Diameter
  Courtesy of MAZDA MOTORS CORP.
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
1. IN: 0.024-0.069 mm {0.0009-0.0027 in}
2. EX: 0.029-0.074 mm {0.0012-0.0029 in}
Maximum Clearance
1. 0.10 mm {0.004 in}
  
  Fig 5: Measuring Valve Stem Clearance
  Courtesy of MAZDA MOTORS CORP.
Measure the protrusion height (dimension A) of each valve guide without lower valve spring seat.
- If not within the specified, replace the valve guide.
Standard Height
1. 12.2-12.8 mm {0.481-0.503 in}
  
  Fig 6: Measuring Valve Guide Protrusion Height
  Courtesy of MAZDA MOTORS CORP.