Section 2 - Cylinder Head - Group 02 Cylinder Head - Rebuild (2-02) M11 Page 2-17 Valve Seats - Grinding Use valve seat grinding machine, Part No. ST-685, and valve guide arbor set, Part No. ST-804, when grinding the valve seat inserts. Install the valve guide arbor (1) in the valve guide with the arbor puller (2). Rotate the arbor to be sure that it is installed correctly. Install the valve seat grinding stone (3), Part No. 3376077, on the driver. Install the grinder unit on the arbor. NOTE: The grinding stone (3) must not be touching the valve seat insert when the drive unit motor is started.
Hold the drive unit in a vertical position and use an and movement of 13 mm [0.50 inch] travel and light pressure to grind the insert. If the area (4) is wider than 2.69mm [0.106 inch], use a grinding stone with a 15 degree angle to narrow the width (5). Remove the grinder unit from the arbor. Install eccentrimeter gauge (6), Part No. ST-685-4, on the arbor. Measure the valve seat to valve guide concentricity. Concentricity (Per 360 Degrees) mm in 0.05 MAX 0.002 If the valve seat concentricity does not meet the speci- fications, grind the valve seat again. If the specifications cannot be met, replace the valve seat insert. Refer to Cylinder Head Valve Seat Insert - Replacement (2-04).