Crankshaft; Piston And Piston Ring; Connecting Rod - Kubota Z400-B Handbuch

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[3] CRANKSHAFT
The crankshaft with the connecting rod converts the recipro·
cating motion of the piston into rotating motion to drive
the oil pump and camshaft.
The crankshaft has oil passages drilled so that oil can flow
from the main bearings to the connecting rod bearings.
The front journal is supported by a sleeve type bearing, the
intermediate journal by a split type, and the rear by a split
type with a thrust bearing.
[4] PISTON AND PISTON RINGS
The piston has a slightly oval shape when cold (in conside·
ration of thermal expansion) and a flat head.
Three rings are installed in grooves in the piston.
The top compression ring (1) is a keystone type, which can
stand against heavy loads, and the barrel face on the rign fits
well to the cylinder wall.
The second compression ring (2) is an undercut type, which
effectively prevents the oil from being carried up.
The oil ring (3) has chamfered contact faces and an expander
ring, which increase the pressure of the oil ring against the
cylinder wall.
Several grooves are cut on the headland area to help heat
dissipate and to prevent scuffing.
The piston pin is lightly offset from the centerline of the
piston toward the major·thrust·face, so that it contacts the
cylinder with minimized "piston slaps."
(1) Top Compression Ring
(2) Second Compression Ring
(3) Oil Ring
[5] CONNECTING ROD
The connecting rod (2) connects the piston and the crank­
shaft, and has bearings at both ends.
A solid type small end bushing (1) is installed between the
piston pin and the rod.
Split type connecting rod bearing (3) is installed between
the crankpin and the rod (2) and between the crankpin and
the rod cap (4).
(1)
Small End Bushing
(2) Connecting Rod
(3) Connecting Rod Bearing
(4) Rod Cap
M·5