(h) After a valve seat insert runout within the
desired limits is obtained, determine the position of
the contact area between the valve and the valve seat
insert. Apply a light coat of Prussian Blue, or similar
paste to the valve seat insert. Next, lower the stem of
the valve in the valve guide and bounce, but do not
rotate the valve on the insert. This procedure will indi-
cate the area of contact on the valve face. The most de-
sirable area of contact is the center of the valve face
and is 3/64 inch to 5/64 inch wide (fig. 3-81).
(i) The 30° valve seat insert face may be ad-
justed, relative to center of valve face, by using 150
and 600 grinding wheels to dress the insert top or open
the insert throat.
(j) After the valve seat inserts have been