Pistons And Cylinders; Removal And Disassembly Of Piston And Connecting Rod - Yanmar BY Series Service Manual

ENGINE

PISTONS AND CYLINDERS

Removal and Disassembly of Piston
and Connecting Rod
CAUTION
Keep the piston pin parts, piston
assemblies, and connecting rod
assemblies together to be returned to
the same position during the
reassembly process. Label the parts
using an appropriate method.
1. Remove cylinder head. See Removal of
Cylinder Head on page 5-23.
2. Remove oil sump and oil pump. See Oil Pump
on page 8-17.
Figure 5-45
3. Remove oil deflector (Figure 5-45, (1)).
IMPORTANT
Use care not to damage the piston cooling
nozzles. The oil spray must hit the piston
precisely. If it does not, the piston will
become too warm resulting in engine
breakdown. Do not straighten damaged
nozzles. They must be replaced.
4. Remove the piston cooling nozzles from the
cylinder block.
5-36
Engines with high operating hours may
have a ridge near the top of the cylinders
that will catch the piston rings and make it
impossible to remove the pistons. Use a
suitable ridge reamer to remove ridges and
carbon prior to removing pistons.
5. Remove the ridge at the top of the cylinder if
necessary.
6. Mark each piston and connecting rod before
removing them. They must be installed in the
0000088en
same location and orientation as they were
removed.
( 1 )
Pistons can fall from cylinder block if engine
0003797
is inverted. Use care when removing the
connecting rod caps.
7. Remove the connecting rod cap bolts
(Figure 5-46).
8. Remove the connecting rod cap and bearing
inserts.
9. Check the bearing oil clearance as each piston
and rod assembly is removed to help determine
extent of wear. See Measuring Oil Clearance on
page 5-63.
Pistons and Cylinders
IMPORTANT
Figure 5-46
IMPORTANT
BY Service Manual