Figure 8. Compressing valve spring..
Then break the seat with a chisel and
A small amount of lubricant may be uaed to ease ine-
remove in two halve
24. Exhaust Valves Seats.
Do not permit drill to par through
(1) Remove valves (par. 22a).
seat and into counterbore of cylinder
(2) Be sure valve guide has been cleaned
or replaced, as necessary (par. 23a).
(3) Inspect each exhaust valve meat for
pitting, signs of fracture, and distortion
(1) Measure outer diameter of oversize
from valve pounding.
seat at room temperature and cut new
(4) Replace an exhaust valve seat that is
valve seat counterbore in cylinder
cracked, deeply pitted, or loose with a
block 0.0035 inch smaller in diameter
0.010 inch oversize meat, following
than seat to be installed, using a
instructions in b and c below.
valve seat cutting tool.
(2) Clean all cuttings from counterbore
valve port and shrink oversize seat by
(1) Remove valve eat with a valve seat
chilling in dry ice for not less than 20
(2) If a pullet is not available, drill two
(3) After chilling, quickly drive seat into
opposing holes through the seat.
counterbore, using seat driving tool or
a soft-faced hammer.