TM 10-4320-344-24
j .
Remove valve seat as follows:
(1) Place mandrel (Figure 4-5, 1) on valve seat and insert guide through mandrel
(1) into valve stem.
Tighten guide so that mandrel (1) is firmly in place.
Do not drill into cylinder head.
Failure to obey this caution will result in
equipment damage.
(2) Insert drill (2) into mandrel (1) and drill through valve seat at two
positions 180° apart.
(3) Remove guide and mandrel (l).
(4) Remove drilled seat.
(5) Measure diameter of valve seat bore in cylinder head (4).
Intake valve seats have larger outside diameter than exhaust valve seats.
(6) Measure outside diameter of new valve seat. Subtract the diameter of bore
from diameter of seat.
Difference must not be less than
0.003 inches (0.076 mm).
Heating cylinder head for more than 30 minutes or at a higher temperature
than 430° F (220° C) may cause cylinder head to warp.
Failure to obey this
caution could result in equipment damage.
k.
Heat cylinder head (4) in oven to a temperature of 430° F (220° C).
Do not
heat cylinder head more than 30 minutes.
Do not touch cylinder head, while it is hot, without protective gloves.
Exercise care when working around hot cylinder head.
Severe burns can result
if protective measures are not taken.
Failure to obey this warning may
result in personal injury.
l .
Remove cylinder head (4) from oven.
If valve guides are in need of replacement.
Replace at this time.
m.
Insert arbor (3) into chamber side of valve guide and drive valve guide out of
cylinder head (4).
n.
Place new retaining ring (Figure 4-2,
8) on new valve guide (9) and drive
longer end of valve guide (9) into bore of cylinder head (1) from the rocker
arm side.
Drive valve guide (9) in until retaining ring (8) seats in valve
o .
Place new valve seat (Figure 4-5,
5) on drift with chamfered side up and drive
valve seat (5) into recess of cylinder head (4).
Ensure that valve seat is
fully inserted.guide bore of cylinder head (1).
4-13
