Gravely Convertible 10 Shop Manual page 35

CRANKSHAFT
1. Keyways - Gears - If keyways for flywheel are badly worn or chipped, replacement of the crankshaft
may be necessary. Broken or badly worn gear teeth will also necessitate replacement of shaft.
2. Crankpin - 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 Clearance Section, are exceeded by more than
.002", it will be necessary to-either replace crankshaft or regrind the crankpin to .010 undersize.
CONNECTING ROD
1. Check bearing area (big end) for excessive wear, score marks, running and side clearance. Replace rod
and cap if worn beyond limits stated.
2. Connecting rods with bearing area .010 undersize are available for use with reground crankpin.
PISTON - PISTON RINGS
Production type and service ring replacement sets are available in the standard size plus .010", .020"
and .030" oversize sets. Cylinder bore must be deglazed before service ring sets are used. Chrome plated
rings, when used, should be installed in the top groove.
1. If the cylinder block does not need reboring and if the old piston is within wear limits and free of score
or scuff marks, it may be reused. Never reuse old rings, however.
2. Remove old rings and clean up grooves.
3. Before installing new rings on piston, place each ring in turn in its running area in cylinder bore and
check end clearance.
4. Rings must be installed according to markings on rings. Generally compression rings must be installed
with groove or bevel up when this is on inside diameter of ring. The chrome ring, when used, must be
installed in the top groove. When bevel is on outside of ring, install in down position or toward skirt.
Ring installation instructions are usually included with new ring sets. Follow instructions carefully.
Use ring expander to install rings and check side clearance of each ring after installation.
PISTON - ROD ASSEMBLY
Normally very little wear takes place in the piston boss-piston pin area. If the original piston and
connect-ing rod can be reused after reconditioning, the pin will usually not have to be replaced. If the
piston boss or
Figure 28 Production Type And Service Type Rings
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