Kohler Comand Pro CH1000 Service Manual page 98

Section 9
Inspection and Reconditioning
NOTE: If the crankpin is reground, visually check to
ensure that the fi llet blends smoothly with
the crankpin surface. See Figure 9-1.
The Fillet Must
Blend Smoothly
with the Bearing
Journal Surface Minimum
Figure 9-1. Crankpin Fillets.
The connecting rod journal can be ground one size
under. When grinding a crankshaft , grinding stone
deposits can get caught in the oil passages, which
could cause severe engine damage. Removing the
crankpin plug when the crankshaft is ground provides
easy access for removing any grinding deposits that
may collect in the oil passages.
Use the following procedure to remove and replace
the plug.
Procedure to Remove Crankshaft Plug:
1. Drill a 3/16 in. hole through the plug in the
crankshaft .
2. Thread a 3/4 in. or 1 in. long self-tapping screw
with a fl at washer into the drilled hole. The fl at
washer must be large enough to seat against the
shoulder of the plug bore. See Figure 9-2.
Self-Tapping Screw
Figure 9-2. Removing Crankpin Plug.
9.2
High Point from
Fillet Intersections
°
45
This Fillet Area
Must Be
Completely Smooth
Flat Washer
Plug
Crankshaft
3. Tighten the self-tapping screw until it draws the
plug out of the crankshaft .
Procedure to Install New Plug:
1. Use a single cylinder camshaft pin, Kohler Part
No. 47 380 09-S as a driver and tap the plug into
the plug bore until it seats at the bott om of the
bore. Make sure the plug is tapped in evenly to
prevent leakage.
Crankcase
Inspection and Service
Check all gasket surfaces to make sure they are free of
gasket fragments. Gasket surfaces must also be free of
deep scratches or nicks.
Inspect the main bearing (if so equipped) for wear or
damage (refer to Section 1, Specifi cations, Tolerances,
and Special Torque Values). Replace the bearing
or crankcase using a miniblock or short block as
required.
Check the cylinder bore for scoring. In severe cases,
unburned fuel can cause scuffi ng and scoring of the
cylinder wall. It washes the necessary lubricating
oils off the piston and cylinder wall. As raw fuel
seeps down the cylinder wall, the piston rings make
metal to metal contact with the wall. Scoring of the
cylinder wall can also be caused by localized hot
spots resulting from blocked cooling fi ns or from
inadequate or contaminated lubrication.
If the cylinder bore is badly scored, excessively worn,
tapered, or out-of-round, resizing is necessary. Use an
inside micrometer to determine the amount of wear
(refer to the Specifi cations, Tolerances, and Special
Torque Values, in Section 1), then select the nearest
suitable oversize of either 0.25 mm (0.010 in.) or
0.50 mm (0.020 in.). Resizing to one of these oversizes
will allow usage of the available oversize piston and
ring assemblies. Initially, resize using a boring bar,
then use the following procedures for honing the
cylinder.
Honing
While most commercially available cylinder hones
can be used with either portable drills or drill presses,
the use of a low speed drill press is preferred as it
facilitates more accurate alignment of the bore in
relation to the crankshaft crossbore. Honing is best
accomplished at a drill speed of about 250 RPM and
60 strokes per minute. Aft er installing coarse stones in
hone, proceed as follows: