Valve Seat Contact

WARNING: This page is about a different car, the 2013 Infiniti FX50. However, it is still accessible from the selected car via links, so may be relevant.

After confirming that the dimensions of valve guides and valves are within the 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 surface.
Check if the contact area band is continuous all around the circumference.

Fig 1: Identifying Proper And Improper Valve Seat Contact Area
Courtesy of NISSAN NORTH AMERICA, INC.
- If not, grind to adjust valve fitting and check again. If the contacting surface still has "NG" conditions even after the re-check, replace valve seat (EXH). Refer to "EXPLODED VIEW ". (Exhaust side)
- If not, replace VVEL ladder assembly & cylinder head assembly. Refer to "EXPLODED VIEW ". (Intake side)
  NOTE: Since the valve seat (INT) cannot be replaced by the piece, VVEL ladder assembly & cylinder head assembly replacement are required.