Komatsu 4D98 Series Shop Manual page 68

4.
Engine Body
Point 6
Piston pin and rings
Disassemble:
l
Use the piston ring replacer (see 11 .l-
10 in Chapter 1 l), remove the piston
rings.
l
Remove the circlip and remove the
piston pin by pushing it out.
Reassemble:
l
Install each piston ring on the piston,
with the punched manufacturer's mark
facing upward.
Reassemble:
l
The piston ring joints shall be stag-
gered at by 120" intervals. Do not po-
sition the top ring joint vertical to the
piston pin. The coil expander joint
shall be opposite to the oil ring joint.
Reassemble:
l
When installing the piston pin to the
rod and piston, the punched match
mark on the big end of the connecting
rod shall be opposite to the size mark
on the piston top.
Reassemble:
l
Install the piston in the cylinder block
with the punched mark on the big end
of the rod on the nozzle side. (The
embossed mark at the connecting rod
l-beam section shall be on the fly-
wheel side.)
Piston ring
the punched manufacturefs
Oil ring joint
TOP ring joint
I
Ring joints
Piston ID
mark
Cylinder size mark
Flywheel side
Pislon ID mark
Embossed mark
Assembly direction of connecting
rod and piston
4-20