Komatsu 4D98 Series Shop Manual page 58

4. Engine Body
(7) Valve guide replacement
Use a valve guide extraction tool (ll.l-
1 in Chapter 11) and extract the valve
guide from the cylinder head.
Put liquid nitrogen or ether (or alcohol)
with dry ice added in a container and
put the valve guide for replacement in it
for cooling. Then insert it in with a valve
guide inserting tool (10.1-2 in Chapter
10).
Check the inside diameter and finish to
the standard inside diameter as re-
quired with a reamer.
Check the projection from the cylinder
head.
I
Valve guide replacement
Valve guide extracting
I
8
inserting tool
Do not touch the cooled valve guide with bare hands to avoid skin damage.
(8) Valve stem seal replacement
Always use a new seal after the intake/exhaust valve is disassembled.
Since the one for the
exhaust valve is marked with yellow paint, do not confuse the intake and exhaust valves.
0
0
Apply engine oil to the lip.
Push with the inserting tool (11 .l-5 in
Chapter 11) for installation.
alve stem s
/
IJ
I inserting tool
/Stem seal
/
Valve guide
Cylinder head
/
Stem seal insertion
4-10