Valve: Testing and Inspection
INSPECT1. Each valve for wear, burn or distortion at its face and stem. Replace as necessary.
2. Valve stem end face for pitting and wear. If pitting or wear is found, valve stem end may be resurfaced. Replace valve if chamfer area is excessively worn.
MEASURE
^ Tools Required:
- J 8001 Dial Indicator Set
- J 26900-1 Outside Micrometer
- J 26900-13 Magnetic Base
Thickness
Thickness of all valve heads using a steel scale. The standard valve thickness is 0.8 to 1.2 mm (0.03 to 0.047 inch). If the intake valve thickness is less than 0.6 mm (0.024 inch), replace the intake valve. If the exhaust valve thickness is less than 0.7 mm (0.027 inch), replace the exhaust valve.
Radial Runout
Each valve for radial runout using a dial indicator with a outside micrometer and V block. To measure runout, rotate valve slowly. If measured runout exceeds limit of 0.08 mm (0.003 inch), replace valve.
Seating Contact Width
NOTE: Produce a contact pattern on each valve by the following procedure.
1. Apply a uniform coat of a smooth coloring compound to the valve seat. There are many compounds available for this purpose. The manufacturer's instructions should be carefully followed to get the proper results.
2. Using a valve lapper, produce a contact pattern on each valve by rotating valve while gently tapping each valve head to the valve seat.
^ The pattern produced on the sealing face of each valve must be a continuous ring without any break. The width of the pattern must be within 1.1 to 1.3 mm (0.0433 to 0.0512 inch) for both intake and exhaust valves.