Guest Blogger: Street Rod 101
Many street rod enthusiasts rebuild their engines. Grinding the valves and seats is often part of this process. Valve positioning is a critical part of reconditioning the cylinder head. The valve cannot be positioning too high, too low, and/or too narrow or wide. It is critical that the valve seat be positioned according to the manufacturer’s specifications. The figure below shows the correct position of the valve seat. For example, if the manufacturer says that the valve seat should be 3/32 inch wide, it should be positioned in the center of the of the valve seat area. This is done by first making a 45 degree cut on the valve seat. Then position the actual contact area
with the valve, by cutting a 30 degrees cut above and a 60 degrees cut below as
shown in the figure. It is critical that the seat be positioned correctly.
--If the valve seat contact area is too wide, the valve and seat may not seal correctly.
--If the valve seat contact area is too narrow, the seat may burn prematurely.
--If the valve seat contact area is too low, the valve may sit too low in the cylinder
--If the valve seat contact area is too high, the valve my sit too high in the