Chery A11. Manual - part 19

CAC Gasoline Engine Maintenance And Servicing Manual

5.Valve, valve spring, valve oil seal, spring seat assembly
removal and

installation：
Removal：
Using special tools for valve compression, take out valve
locking pieces, don't compress spring excessively, compress
spring enough to slip locking pieces out of its stroke, or valve
stem may be bent.
If valve locking pieces do not come out during spring
compression, remove compression tools, put an appropriate

pipe on spring seat， so the valve locking piece will not be
impacted. Put a wooden block on valve head (with cylinder
head combustion chamber facing workbench), and then strike
pipe end with hammer.
Reinstall special tools for valve spring compression, locking
pieces may be taken out. After locking piece is taken out,
remove compression tools by unbolting slowly.
——Remove valve spring seat and valve spring，take out
valve oil seal spring seat assembly with screwdriver， and
valve oil seal spring seat must be replaced.

——Overturn cylinder head ，remove intake and exhaust
valves.

——Keep each set of valve, valve locking pieces, valve
spring, spring seat in the same plastic bag and mark numbers
on it, so the parts may be installed in the original place.

——Valve standard sizes and clearance：

Unit：Mm

Intake valve

Exhaust valve

grade

Valve stem

diameter

Valve guide

hole

diameter

Clearance

Valve stem

diameter

Valve guide

hole

diameter

Clearance

standard

8.043+0

-0.018

8.063-8.094

8.017+0

-0.018

8.063-8.094

oversize0.4

8.443+0

-0.018

8.463-8.494

0.02-0.069

8.417+0

-0.018

8.463-8.494

0.046-0.095

Fig.38

Fig. 39

Fig. 40

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CAC Gasoline Engine Maintenance And Servicing Manual

——Measure valve spring free length and spring force:

——Grinding the valve and the valve seat with the valve
conical angle(Intake valve and exhaust valve):

44°30′— 45°30′

valve seat sealing width:

1.75 — 2.32mm

Installation:
——Before installation, make sure that cylinder head has been
cleaned without any grinding material on cylinder head, valve or

valve guide .
——Lubricate the valve stem and guide with clean engine oil.
——Install the valve. notice that the intake and exhaust valve for 478
and 480 are not interchangeable .refer to the previous valve mark for
valve assembly.
——Press  the  valve  spring  assembly  with  oil  seal  onto  the  top  of
valve  guide.  apply  engine  oil  on  the  intake  and  exhaust  valve  guide
edge  where  the  valve  seals  are  installed    for  preventing  valve  lock
piece  groove  from  damaging  oil  seal  lip.  You  may  protect  the  valve
lock groove with tape and remove the tape after installing the valve.

——Install the valve spring and spring seat. Compress the spring seat
to expose the lock piece groove with a special compression tool. Then
put the lock pieces into it and release the compression tool slowly and
remove the tool .
——Put the cylinder head on a wood lump after all lock pieces are
assembled. And tap the small head of the valve stem with a plastic or
copper hammer to fit for the valve mechanism.

Compression (mm)

Spring load (N)

Spring free length

=37.084

422

=27.7

892.7

=27.0

945

=47.2

Fig.42

Fig.43

Fig.44

Fig.45

Fig.42

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CAC Gasoline Engine Maintenance And Servicing Manual

6.the sizes for intake valve, intake valve seat, exhaust valve seat and valve guide

―the size of intake valve seat and cylinder head valve seat hole

―

the size of exhaust valve seat and cylinder head valve seat hole

—

——the size of valve guide and valve guide hole

Diameter. of intake

valve seat

Diameter of the

cylinder head

valve seat hole

press fit
clearance

Standard

478

41.877

+0.01

-0.01

41.763

+0.025

oversize

0.5

42.377

+0.01

-0.01

42.263

+0.025

oversize

1.0

42.877

+0.01

-0.01

42.763

+0.025

0.079—0.124

Standard

480

43.877

+0.01

-0.01

44.763

+0.025

oversize

0.5

44.377

+0.01

-0.01

44.263

+0.025

oversize

1.0

44.877

+0.01

-0.01

44.763

+0.025

0.079—0.124

Diameter. of intake

valve seat

Diameter of the

cylinder head

valve seat hole

press fit

clearance

Standard

478

35.377

+0.01

-0.01

35.263

+0.025

oversize 0.5

35.877

+0.01

-0.01

35.763

+0.025

oversize 1.0

36.377

+0.01

-0.01

36.263

+0.025

0.079—0.124

Standard

480

38.377

+0.01

-0.01

38.263

+0.025

oversize 0.5

38.877

+0.01

-0.01

38.763

+0.025

oversize 1.0

39.377

+0.01

-0.01

39.263

+0.025

0.079—0.124

Level

The valve guide

hole

The diameter. of

cylinder head tube

hole

press fit

clearance

Standard

13.555

-0.01

13.481-13.519

oversize

14.305

-0.01

14.231-14.269

oversize

14.505

-0.01

14.481-14.519

0.026-0.07

Fig.46

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CAC Gasoline Engine Maintenance And Servicing Manual

【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

——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

77.22—77.23

79.94—79.95

77.23—77.24

79.95—79.96

77.24—77.25

79.96—79.97

Factory

group

77.25—77.26

79.97—79.98

77.51—77.52

80.23—80.24

77.52—77.53

80.24—80.25

Factory

repair

77.53—77.54

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

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