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10. PISTON/CRANKSHAFT/CYLINDER BLOCK
The crankshaft and the cylinder block convert the compression pressure to the rotating energy.
Components ▶
Cylinder block
Piston
Connecting rod
Crankshaft
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(3) Functions
Piston transfers the combustion energy from engine to connecting rod. Especially in the direct
injection engine such as D20DTF, it provides the combustion space and largely effects to the
engine performance and exhaust gas.
Piston ring
#1 ring (Top ring) : Prevents the high pressurized combustion gas from leaking into crank
chamber, and prevents the engine oil getting into combustion chamber.
#2 ring: Scrapes the engine oil on the cylinder bore, and prevents the leaked combustion gas
from #1 ring from leaking into the crank chamber.
Oil ring: Scrapes the engine oil on the cylinder bore.
Piston pin
Connects the piston the connecting rod, and transfers the linear movement of piston to
connecting rod to convert it to rotating energy
Snap pin
Locks the piston pin. ▶
-
-
-
▶
-
▶
-
(4) Assembling the piston
Install the piston rings with the "Y" mark on
the ring facing upwards.
Position the end gap of #1 ring at 180˚
away from the end gap of #1 ring.
Position the end gap of oil ring at 180˚
away from the end gap of coil spring, and
position the end gap of oil ring at 90˚ away
from the end gap of #2 ring. 1.
2.
3.
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Selecting piston oversize
Top of piston Top of cylinder block
EnginePiston Cylinder bore
Part NO Marking NO.-
D20DTF 671 030 06 17 - -
671 037 07 01 A A
671 037 08 01 X X
671 037 09 01 B B
671 037 10 01 +5 -
671 037 11 01 +10 -
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3) Crankshaft
(1) Overview
Crankshaft is installed on the cylinder block.
(2) Arrangement
Crankshaft main bearing upperCrankshaft main bearing upper
Upper thrust bearing
Crankshaft main bearing lowerCrankshaft main bearing lower
Lower thrust bearing
Crank pin journalMain journal
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Bottom of cylinder block
Selection of upper main bearing
Mating surface of crankshaft sprocket
Selection of lower main bearing
(3) Selection of crankshaft main bearing
Mark Color Thickness of main
bearing (mm)
V Violet +0.030
+0.025
W White +0.025
+0.020
R Red +0.020
+0.015
Y Yellow +0.015
+0.010
B Blue +0.010
+0.005
2.25
2.25
2.25
2.25
2.25
Selection of bearing according to pin
punch & color
Mark Color Thickness of main
bearing
* Blue 66.500~66.506
** Yellow 66.506~66.513
*** Red 66.513~66.519
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4) Cylinder Block
(1) Overview
The major dimensions in D20DTR are similar to
D20DTR engine. It has two mounting
bosses for knock sensor and meets the
requirements for EURO5 regulation.
(2) Layout
Right sideCylindrical pin
Expansion plug
Screw plug
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Left sideExpansion plug
(3) Features
For simple manufacturing, the crankcase
blow-by gas passage and the oil return hole
are made by casting on the cylinder block.
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The bottom side of water jacket is desgined as sine wave to strengthen the structure of crankcase.
The main flow of coolant starts from outlet port of water pump and goes along the longitudinal
direction of engine. The coolant passage from cylinder head to inlet port of water pump is
integrated in cylinder head.
The engine oil from oil pump is supplied to the main oil gallery through oil channel, oil filter
module and cross bore in cylinder block without using external pipes. This oil is supplied to main
bearing, cylinder head and MBU. And, it is sprayed to the chain through the chain tensioner
connected to cross bore.
Crankcase cross bore for oil supply
Water jacket core