Kohler K9J Service Manual page 109

Valve Guides
If a valve guide is worn beyond specifications, it
will not guide the valve in a straight line. This may
result in a burnt valve face or seat, loss of com-
pression, and excessive oil consumption.
To check valve guide to valve stem clearance,
thoroughly clean the valve guide and, using a
split-ball gauge, measure the inside diameter.
Then, using an outside micrometer, measure the
diameter of the valve stem at several points on
the stem where it moves in the valve guide. Use
the largest stem diameter to calculate the clear-
ance. On models K91, K161 and K181, the clear-
ance should not exceed .005" for intake and
.007'' for exhaust valves. On models K241, K301,
K321 and K341, the clearance should not exceed
.006" for intake and .008" for exhaust valves. If
the clearance exceeds these specifications, deter-
mine whether the valve stem or the guide is re-
sponsible for the excessive clearance.
NOTE: The exhaust valves on these engines have
a slightly tapered valve stem to help prevent stick-
ing. Because of the taper, the valve stem must be
measured in two places to determine if the valve
stem is worn. If the valve stem diameter is within
specifications, replace the valve guide. See Figure
11-5.
Remove Valve Guide
The valve guides are a tight press fit in the cylin-
der block. A valve guide removal tool is recom-
mended to remove the guides (refer to "Special
Tools" section). To remove valve guide, refer to
Figure 11-6 and proceed as follows:
Slide
Hammer
Valve
Guide
Stud- 5/16"
X
2-1/2"
Figure 11-6. Pulling Valve Guide.
1. Install 5/16-18 NC nut on coarse threaded end
of 2-1/2" long stud (K161 and K181) or 3-1/2"
long stud (K241,K301,K321, and K341).
11.6
2. Insert other end of stud through valve guide
bore and install 5/16-24 NF nut. Tighten both
nuts securely.
NOTE: Valve guide must be held firmly by the stud
assembly so that all slide hammer force will act on
the guide.
3. Assemble the valve guide removal adapter to
the stud and then the slide hammer to the
adapter.
4. Use the slide hammer to pull the guide out.
Install Valve Guide
To install valve guide, proceed as follows:
1 . Make sure valve guide bore is clean and free
of nicks or burrs.
2. Using valve guide driver (refer to "Special
Tools" section), align and then press guide in
until valve guide driver bottoms on valve guide
counterbore.
3. Valve guides are often slightly compressed
during insertion. Use a piloted reamer and
then a finishing reamer to resize the guide
bore to .3125" for K161, K181, K241, K301,
K321 , and K341 . Refer to Figure 11-7.
Figure 11-7. Reaming Valve Guide.
Valve Seat Inserts
The intake valve seat is usually machined into the
cylinder block, however, certain applications may
specify a hard alloy insert. If the seat becomes
badly pitted, cracked, or distorted, the insert must
be replaced.
The insert is a tight press fit in the cylinder block.
A valve seat removal tool is recommended for this
job (refer to "Special Tools" section). Since insert
removal causes loss of metal in the insert bore
area, use only Kohler service replacement inserts,
which are slightly larger to provide proper retention
in the cylinder block. Make sure new insert is
properly started and pressed into bore to prevent
cocking of the insert.