CHAPTER 2 8354/8404
2-8
D615-W02 May-2003
615W212A
615W211A
615W210A
C. CRANKSHAFT
The crankshaft is made of forged steel and the journals,
the crankpins and the bearing surface for the oil seal
are induction-hardened to increase wear resistance.
Each crankshaft journal is supported by the main bear-
ing case (3) having a bearing inside. The front bearing-
crankshaft bearing (2) is a solid type bushing and rear
and intermediate bearings are a split type. The
crankshaft, crankshaft bearings have oil holes for lu-
bricant flow.
D. PISTON AND PISTON RINGS
The piston is made of an aluminum alloy which is tem-
perature and pressure resistant. Three rings are in-
stalled in the grooves of the piston. The top ring (1) is a
keystone type, which can withstand heavy loads, and
the barrel face on the ring fits well to the cylinder wall.
The second ring (2) is an undercut type, which pre-
vents the oil from being carried up. The oil ring (3) has
chambered contact faces and an expander ring, which
increase the pressure of the oil ring against the cylin-
der wall to scrape the oil. The top ring is plated with
hard chrome to increase wear resistance (The ring of
4A200T engine is made of a special steel).
E. CONNECTING ROD
The connecting rod (2), which converts the reciprocat-
ing motion of the pistons caused by the fuel combus-
tion into the rotating motion of the crankshaft, is made
of hard forged steel. The connecting rod has bearings
at both ends. The small end has a solid type bearing
(small end bushing (2)) and the big end has a split
type bearing (crankpin bearing (3)).
(1) Top Ring (3) Oil Ring
(2) Second Ring
(1) Small End Bushing (3) Crankpin Bearing
(2) Connecting Rod
(1) Crankshaft (4) Crankshaft Bearing 2
(2) Crankshaft Bearing 1 (5) Thrust Bearing
(3) Main Bearing Case
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