Kohler COMMAND CH18, Service Manual

Page: 185 / 232

10.2
Section 10
Inspection and Reconditioning
Inspect the crankshaft bearing surfaces for scoring,
grooving, etc. Some engines have bearing inserts in
the crankshaft bore of the closure plate and/or
crankcase. Do not replace bearings unless they show
signs of damage or are out of running clearance
specifications. If the crankshaft turns easily and
noiselessly, and there is no evidence of scoring,
grooving, etc., on the races or bearing surfaces, the
bearings can be reused.
Inspect the crankshaft keyways. If they are worn or
chipped, replacement of the crankshaft will be
necessary.
Inspect the crankpin for score marks or metallic
pickup. Slight score marks can be cleaned with crocus
cloth soaked in oil. If the wear limits, as stated in
“Specifications and Tolerances” are exceeded, it will
be necessary to either replace the crankshaft or regrind
the crankpin to
0.25 mm (0.010 in.) undersize. If
reground, a 0.25 mm (0.010 in.) undersize connecting
rod (big end) must then be used to achieve proper
running clearance. Measure the crankpin for size,
taper, and out-of-round.
NOTE: If the crankpin is reground, visually check to
ensure that the fillet blends smoothly with
the crankpin surface. See Figure 10-1.
Procedure to Remove Crankshaft Plug:
1. Drill a 3/16" hole through the plug in the
crankshaft.
2. Thread a 3/4" or 1" long self-tapping screw with a
flat washer into the drilled hole. The flat washer
must be large enough to seat against the shoulder
of the plug bore. See Figure 10-2.
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 bottom of the
bore. Make sure the plug is tapped in evenly to
prevent leakage.
45
°
High Point from
Fillet Intersections
This Fillet Area
Must Be
Completely Smooth
Minimum
The Fillet Must
Blend Smoothly
with the Bearing
Journal Surface
Figure 10-1. 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.
Figure 10-2. Removing Crankpin Plug.
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, “Specifications, Tolerances,
and Special Torque Values”). Replace the crankcase
using a miniblock or short block as required.
Flat Washer
Self-Tapping Screw
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Plug
Crankshaft