Chery SQR 7160 sedan. Manual — part 29
CAC Gasoline Engine Maintenance And Servicing Manual
34
【9】: Removal and installation of the piston and rod assembly.
Removal:
——Remove the crankshaft to the bottom dead center of the
cylinder. Check and make sure that there is a cylinder mark on the
connecting rod and its cap. or make a mark on each cylinder
before removal.
——Remove the connecting rod bolts and remove the rod cap.
Take the connecting rod bushing out and stick on cylinder marks
and labels on the upper or lower halves.
——Push the connecting rod and piston out of the cylinder with a
hammer wood handle. Take the piston and rod out.
——Remove the piston ring with a special tool or the piece of
feeler gauge. And make labels on each cylinder and upper and
lower halves.
——Press the piston pin out of the piston hole and connecting rod
small end with a press . Then put the piston, piston ring and piston
pin together.
Cleaning and inspection:
——Clean and remove the carbon deposits from the piston, piston
ring and piston pin.
——Clean and remove the carbon deposits from the upper
cylinder bore.
——Measure the diameter of cylinder bore. unit: mm
U
——Grind the cylinder bore with the service gauge and the
figured
twins angle is 50°—60°.
——Measure the diameter of each piston of the carburetor
engine.
Measurement should be taken at the position 10mm to the
bottom
skirt. For 480E piston, measurement should be taken at the
478 cylinder bore
480 cylinder bore
1
77.22—77.23
1
79.94—79.95
2
77.23—77.24
2
79.95—79.96
3
77.24—77.25
3
79.96—79.97
Factory
group
4
77.25—77.26
4
79.97—79.98
A
77.51—77.52
A
80.23—80.24
B
77.52—77.53
B
80.24—80.25
Factory
repair
C
77.53—77.54
C
80.25—80.26
standard
77.245—77.255
standard
79.965—77.975
Increase
0.29
77.525—77.535
oversize
0.29
80.245—80.255
For
mainte
nance
Increase
0.5
77.745—77.755
oversize
0.5
80.466—80.475
Fig.47
Fig.48
Fig.49
Fig.50
CAC Gasoline Engine Maintenance And Servicing Manual
35
position 19mm to the bottom skirt.
unit：mm
*
480M piston should be applied on 480E
engine
——Measure the diameter. of the hole of piston pin
unit：mm
478
diameter of the piston
pin hole
480
diameter. of the
piston pin hole
White
20.630—20.633
White
20.630—20.633
Red
20.633—20.636
Red
20.633—20.636
Blue
20.636—20.639
Blue
20.636—20.639
——Measure the diameter. of piston pin
unit：mm
478
diameter. of the
piston pin hole
480
diameter. of the piston
pin hole
White
20.622—20.625
White
20.622—20.625
Red
20.625—20.628
Red
20.625—20.628
Blue
20.628—20.631
Blue
20.628—20.631
——Measure cotter intermission of piston ring
first compression ring 0.30—0.50mm
second compression ring 0.30—0.50mm
Steel combination oil ring 0.40—1.40mm
——Measure the piston ring end play in the piston groove
unit：mm
478 dia. of piston
skirt(mm)
488 dia. of
piston skirt
(mm)
480E *dia. of
piston skirt (mm)
1
77.19—77.20
79.91—79.92
79.915—79.925
2
77.20—77.21
79.92—79.93
79.925—89.935
3
77.21—77.22
79.93—79.94
79.935—79.945
factory
group
4
77.22—77.23
79.94—79.95
79.945—79.955
A
77.48—77.49
80.20—80.21
80.205—80.215
B
77.49—77.50
80.21—80.22
80.215—80.225
Factory
repair
C
77.50—77.51
80.22—80.23
80.225—80.235
standard
77.21—77.23
5
79.93—79.95
5
79.965—79.975
oversize
0.29
77.49—77.51
5
80.21—80.23
5
80.245—80.255
Spare
parts
oversize
0.5
77.71—77.73
5
80.43—80.45
5
80.465—80.475
piston ring
height
piston ring
groove size
Fit clearance
first compression
ring
1.60
0
-0.012
1.6
+0.06
+0.04
0.050—0.082
second track
compression ring
2.0
0
-0.012
2.0
+0.06
+0.04
0.050—0.082
0.61±0.025
Oil control ring
blade
oil control ring
2.68±0.05
4.0
+0.03
0.01
0.01—0.23
Cast iron oil control
ring
4.0
-0.015
-0.025
4.0
+0.03
+0.01
0.025—0.055
Fig.51
Fig.52
CAC Gasoline Engine Maintenance And Servicing Manual
36
——Measure the crosshead end bore of the connecting rodФ20.589
+0.02
0
CAC Gasoline Engine Maintenance And Servicing Manual
37
——Check and make sure that the oil injection hole of the
connecting rod large end is not blocked. The outside diameter is
φ1mm.
Installation:
——Need not to divide into groups for the piston weight, piston
pin holes and the accessory piston skirt. Before assembling, check
the piston head mark and make sure that it is in accord with
cylinder No.4.
——Heat the small end of connecting rod to 230°—400℃, and
apply SAE50 engine oil or graphite colloid oil on the outer
circumference of the piston pin hole. Then press the piston pin
into the hole of connecting rod small end and piston pin. One end
of the piston pin may be 0.7mm mostly out of the pin hole or
0.3mm mostly in the seat. And plug the other end of it into the pin
seat.
The piston head means the front arrow. The outer end of
piston pin means the front lug, which should has a same
direction with “F” near the large end of the connecting
rod.(with ‘480’ mark on some blanks and the mark side
forward.)
——After the piston, piston pin, and the connecting rod are put
together, print and sculpture the cylinder numbers with the 3mm
words on the top of piston, the connecting rod and the left side of
rod cap(viewed from the front). Be sure not to be deformed on the
connecting side during printing.
——The dimension of piston ring.
478 piston ring
480 piston ring
Paint marker (group)
Size
of
gauge
Paint
marker
(group)
Size
of
gauge
Yellow paint +no paint
(standard)
77.22
No
paint
(standard)
79.94
Yellow paint+ purple
paint (oversize 0.29)
77.51
Purple
paint
(oversize 0.29)
80.23
Yellow
paint
+blue
paint (oversize 0.5)
77.72
Blue
paint
(oversize 0.5)
80.44
——When installing the piston ring, the mark side should
be put up and the second compression ring outside cut section
should be put down and remember not to the contrary. Firstly the
oil controlling ring, then the second compression ring, and finally
the first compression ring. As assembling the ring, its maximum
tension should be inferior to the diameter of the cylinder(+1.
65mm), or the ring would be deformed and broken. The two
cotters of the steel band combination oil ring and oil control
spacer ring should be parted with a angle of 120°. And the
cotters of cast iron oil ring and screw spacer ring should be parted
with a interval of 180°. The piston should rotate freely in the ring
groove without blocking.
Fig.53
Fig.54
Fig.55
Front
lug
No.1 compressing
ring
No.2
compressing
ring
Steel
band
combination oil
ring
Cost iron oil ring
Only one
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