B4000 SE Cab Plus 4WD V6-4.0L OHV (1997)
Valve Seat: Testing and Inspection
1. Inspect the contact surface of the valve seat and valve face for the following:
(1) Roughness
(2) Damage
2. If necessary, resurface the valve seat by using a 45° valve cutter and/or resurface the valve face.
3. Apply a thin coat of Prussian blue to the valve face.
4. Check the valve seating by pressing the valve against the seat.
(1) If blue does not appear 360° around the valve face, replace the valve.
(2) If blue does not appear 360° around the valve seat, resurface the seat.
5. Measure the valve seat contact width.
Width: 1.524-2.000 mm (0.060-0.079 inch)
6. Check the valve seat runout with a valve seat runout gauge, as illustrated. Follow the instructions of the gauge manufacturer. If the runout exceeds
the wear limit, resurface the valve and valve seat.
Runout Limit: 0.0381 mm (0.0015 in)