Kohler Command PRO ECV630 Service Manual page 102

Disassembly/Inspection and Service
Remove Crankshaft
Carefully pull crankshaft from crankcase.
Inspection and Service
Crankshaft Components and Details
A Self-Tapping Screw
C Plug
G
E
Fillet Must Blend Smoothly with Bearing Journal
E
F High Point from Fillet Intersections
G
H This Fillet Area Must Be Completely Smooth
NOTE: If crankpin is reground, visually check to ensure
fillet blends smoothly with crankpin surface.
Inspect gear teeth of crankshaft. If teeth are badly worn,
chipped, or some are missing, replacement of crankshaft
will be necessary.
Inspect crankshaft bearing surfaces for scoring,
grooving, etc. Some engines have bearing inserts in
crankshaft bore of oil pan and/or crankcase. Do not
replace bearings unless they show signs of damage or
are out of running clearance specifications. If crankshaft
turns easily and noiselessly, and there is no evidence
of scoring, grooving, etc., on races or bearing surfaces,
bearings can be reused.
Inspect crankshaft keyways. If they are worn or chipped,
replacement of crankshaft will be necessary.
102
A
B
C
D
B Flat Washer
D Crankshaft
F
H
Surface
45° Minimum
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Inspect crankpin for score marks or metallic pickup.
Slight score marks can be cleaned with crocus cloth
soaked in oil. If wear limits, as stated in Specifications
and Tolerances are exceeded, it will be necessary to
either replace crankshaft or regrind 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 crankpin for
size, taper, and out-of-round.
Connecting rod journal can be ground one size under.
When grinding a crankshaft, grinding stone deposits
can get caught in oil passages, which could cause
severe engine damage. Removing crankpin plug when
crankshaft is ground provides easy access for removing
any grinding deposits collected in oil passages.
Use these following procedures to remove and replace
plug.
Procedure to Remove Crankshaft Plug:
1. Drill a 3/16 in. hole through plug in crankshaft.
2. Thread a 3/4 in. or 1 in. long self-tapping screw with
a flat washer into drilled hole. Flat washer must be
large enough to seat against shoulder of plug bore.
3. Tighten self-tapping screw until it draws plug out of
crankshaft.
Procedure to Install New Plug:
Use a single cylinder camshaft pin, as a driver and tap
plug into plug bore until it seats at bottom of bore. Make
sure plug is tapped in evenly to prevent leakage.
Remove Flywheel End Oil Seal
Remove oil seal from crankcase.
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 main bearing (if so equipped) for wear or
damage (refer to Specifications). Replace crankcase
using a miniblock or short block as required.
Check cylinder bore wall for scoring. In severe cases,
unburned fuel can cause scuffing and scoring of cylinder
wall. It washes necessary lubricating oils off piston and
cylinder wall. As raw fuel seeps down cylinder wall,
piston rings make metal to metal contact with wall.
Scoring of cylinder wall can also be caused by localized
hot spots resulting from blocked cooling fins or from
inadequate or contaminated lubrication.
If cylinder bore is badly scored, excessively worn,
tapered, or out-of-round, resizing is necessary. Use an
inside micrometer to determine amount of wear (refer
to Specifications), then select 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
available oversize piston and ring assemblies. First,
resize using a boring bar, then use these following
procedures for honing cylinder.
24 690 02 Rev. D