Yanmar 3TNV Series Service Manual page 83

4. Disassembly, Inspection and Reassembly of Engines
Step
1) Remove main bearing cap bolt. While
shaking main bearing cap, remove main
bearing cap together with lower main bearing
metal.
2) Extract crankshaft, taking care not to damage
it.
3) Remove upper main bearing metal.
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1) Remove piston and connecting rod assembly.
24
2) Remove tappet.
25
Removal Parts
1) Before extracting crankshaft, measure the
side gap around it.
Apply a dial gauge to the end of crankshaft.
Force the crankshaft on both sides in the axial
direction to measure the thrust gap.
Alternatively, insert a thickness gauge directly
between the base thrust metal and the thrust
surface of the crankshaft to measure the gap.
If the limit size is exceeded, replace the thrust
metal with a new one.
Thrust gap (All models)
2) Notice on the removal of thrust metal.
a) When removing thrust metal, ascertain the
position and direction where thrust metal is
installed in relation to the cap.
b) Make sure that the thrust metal groove is
outward in relation to the cap.
1) To selectively remove a desired piston and
connecting rod assembly without extracting
crankshaft, take the steps itemized below:
a) Remove carbon deposits from the upper wall
of the cylinder using fine sandpaper, taking
care not to damage the inner surface of the
cylinder.
b) While turning the crankshaft, with the
connecting rod cap removed, raise the
piston up to the top dead center (TDC).
c) Extract the piston/connecting rod assembly
while tapping the connecting rod at the large
end with the handle of a plastic hammer or the
like.
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Remarks