Valve and Valve Seat Grinding

VALVE AND VALVE SEAT GRINDING





Seating of valves must be perform for engine assembly to deliver optimum power and to deliver optimum performance. Another important factor is the cooling of the valve heads. Good contact between each valve and its seat in the cylinder head is necessary to insure that heat in the valve head will be properly carried away.
Several different types of equipment are available for reconditioning valve seats. Carefully follow the equipment manufacturer recommendations to attain proper results. Regardless of what type of equipment is used, it is essential that valve guide bores be free from carbon and/or free from dirt to endure proper centering of the pilot in the guide.
Valves that are slightly pitted can be refaced to proper angle, insuring correct relation between head and stem, in a valve refacing mechanism. Replace valve stems which show excessive ware. Replace valves that are warped excessively. Replace the valve if the edge of the valve head is less than 1.6 mm (0.0625 inch) thick after grinding.
Use a 30 degrees and a 60 degrees stone to control valve seat width.








Grind the valves at a 90 degrees 40 degree angle. Grind the valve seat at a 90 degrees angle. The 40' difference in angles provides better sealing. The valve seat width should be:
- The intake valve seat width should be: 1.0 - 1.4 mm (0.039 - 0.055 inch).
- The exhaust valve seat width should be: 1.4 - 1.8 mm (0.055 - 0.070 inch).