2012 SSANGYONG NEW REXTON oil

1) Piston
(1) Overview
Piston assembly contains piston, #1 ring, #2
ring, oil ring, piston pin and snap ring. The
expansion energy from engine is transferred to
the crankshaft through connecting rod to convert
the linear movement to rotating energy.
(2) Layout
#1 ring
Oil ring
Snap ring
#2 ringMaterial: B2+
Skirt coating:
MoS2
Piston cooling gallery for
connecting rod
Wide bawl type (CR 16.5)
Cooling jet

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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.
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-
-
-
-
(4) Assembling the piston
Install the piston rings with the "Y" mark on the
ring facing upwards.
away from the end gap of #1 ring.
away from the end gap of coil spring, and
from the end gap of #2 ring. 1.
2.
3.

NoConnecting
rod/ Bore
diameter in
big endUpper bearing Lower bearing
Journal
diameter of
crank pinOil
clearance of
bearing
GradeBearing
thicknessGradeBearing
thickness
1
54.600 R 1.804
B 1.812
50.935 0.017
1.808 1.815 0.063
2
Y 1.808
Y 1.809 0.016
54.614 1.812 1.812
50.960 0.062
3
B 1.812
R 1.806 0.015
1.816 1.809 0.061
Min. 0.015
Max. 0.063
(3) Selection of crankshaft pin journal bearing
The connecting rod bearing contains 3 sets of 3 grades in upper and lower sections.
Three sets in the table below have nearly same oil clearance (0.015~0.063 mm) of bearing.
Identification: Coloe mark on bearing side surface -
-
-
Oil clearance of connecting rod bearing

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

2. MAINTENANCE AND INSPECTION
1) Maintenance Procedures for DI Engine Fuel System
Always keep the workshop and lift clean (especially, from dust).
Always keep the tools clean (from oil or foreign materials).
Wear a clean vinyl apron to prevent the fuzz, dust and foreign materials from getting into fuel system.
Wash your hands and do not wear working gloves. 1.
2.
3.
Follow the below procedures before starting service works for fuel system.
If the problem is from HP pump, fuel supply line or injector, prepare the clean special tools and sealing
caps to perform the diagnosis for DI engine fuel system in this manual. At this point, thoroughly clean
the related area in engine compartment. 4.
Clean the engine compartment before starting service works.
Tool kit for high pressure lineTook kit for low pressure line

(2) Di engine and its expected problems and remedies can be caused by
water in fuel
System supplement against paraffin separation
In case of Diesel fuel, paraffin, one of the elements, can be separated from fuel during winter and then
can stick on the fuel filter blocking fuel flow and causing difficult starting finally. Oil companies supply
summer fuel and winter fuel by differentiating mixing ratio of kerosene and other elements by region and
season. However, above phenomenon can be happened if stations have poor facilities or sell improper
fuel for the season. In case of DI engine, purity of fuel is very important factor to keep internal
preciseness of HP pump and injector.
Accordingly, more dense mesh than conventional fuel filter is used. To prevent fuel filter internal clogging
due to paraffin separation, SYMC is using fuel line that high pressure and temperature fuel injected by
injector returns through fuel filter to have an effect of built-in heater (see fuel system).
System supplement and remedy against water in fuel
As mentioned above, some gas stations supply fuel with excessive than specified water. In the
conventional IDI engine, excessive water in the fuel only causes dropping engine power or engine
hunting. However, fuel system in the DI engine consists of precise components so water in the fuel can
cause malfunctions of HP pump due to poor lubrication of pump caused by poor coating film during high
speed pumping and bacterization (under long period parking). To prevent problems can be caused by
excessive water in fuel, water separator is installed inside of fuel filter. When fuel is passing filter, water
that has relatively bigger specific gravity is accumulated on the bottom of the filter.
Water drain from water separator
If water in the separator on the fuel filter exceeds a certain level, it will be supplied to HP pump with fuel,
so the engine ECU turns on warning lamp on the meter cluster and buzzer if water level is higher than a
certain level.
Due to engine layout, a customer cannot easily drain water from fuel filter directly, so if a customer
checks in to change engine oil, be sure to perform water drain from fuel filter.
Water
separator
To separate the water from the fuel filter,
remove the fuel filter assembly first.

2. INSPECTION
1) Troubleshooting
When Abnormal Noises are Heard from the Engine Room
For the vehicle equipped with DI engine, if a learning noise occurs in each range or other noises
occur, the major cause of it is a faulty turbocharger assembly. But an interference issue, poor
tightness or loose in the intake and exhaust system also can cause those noises. This is mainly
because the operator didn't follow the instruction exactly when reconnecting the intake hoses and
pipes which were disconnected to check the system or replace the air cleaner. If the intake system is
free of any faults, check the EGR and PCV oil separator connected to the intake system.
The figure may be different from the actual engine. Therefore, read thoroughly below before replacing
the parts.
2) Abnormal Noise Caused by Poor Tightness of Intake System
When the DI engine is running, the air entered into the engine flows in the sequence as shown above. If
high intake pressure is applied to the loose or damaged part, a whistling noise may occur, the intake air
volume is measured incorrectly or the engine power is derated.