Valve Inspection

WARNING: This page is about a different car, the 2005 Mazda MX-5 Miata, 2004 Mazda MX-5 Miata, and 2003 Mazda MX-5 Miata. However, it is still accessible from the selected car via links, so may be relevant.

Measure the valve head margin thickness of each valve. Replace the valve as necessary.
Margin Thickness
1. IN: 0.9 mm {0.035 in} min.
2. EX: 1.0 mm {0.039 in} min.
  
  Fig 1: Measuring Margin Thickness
  Courtesy of MAZDA MOTORS CORP.
Measure the length of each valve. Replace the valve as necessary.
Standard Length
1. IN: 101.71-102.31 mm {4.0044-4.0279 in}
2. EX: 101.71-102.31 mm {4.0044-4.0279 in}
Minimum Length
1. IN: 101.61 mm {4.0004 in}
2. EX: 101.61 mm {4.0004 in}
Measure the stem diameter of each valve in X and Y directions at the three points (A, B, and C) shown. Replace the valves as necessary.
Standard Diameter
1. IN: 5.970-5.985 mm {0.2351-0.2356 in}
2. EX: 5.965-5.980 mm {0.2349-0.2354 in}
Minimum Diameter
1. IN: 5.920 mm {0.2331 in}
2. EX: 5.915 mm {0.2329 in}