Valve Seat Contact

After confirming that the dimensions of valve guides and valves are within specifications, perform this procedure:

• Apply Prussian blue (or white lead) onto contacting surface of valve seat to check the condition of the valve contact on the seat surface.
  Fig 1: Determining Valve Seat Contact

  Courtesy of NISSAN MOTOR CO., U.S.A.
• Check if the contact area band is continuous all around the circumference.
• If not, grind to adjust valve fitting and check again. If the contacting surface still has N.G. conditions even after the re-check, replace the valve seat.