Chery A18. Manual — part 32

Grinding valve and valve seat ring

UAES’s new

two-valve

Face angle of intake valve

44º30′---45º30′

Width of the sealing band

for the intake valve seat

ring

1.75---2.32mm

Face angle of exhaust

valve

91º (0º-0º30ˊ)

Width of the sealing band
for the exhaust valve seat

ring

1.44±0.1

Installation
Before installation, the cylinder head shall be
completely cleaned and there shall be no any trace
of abrasive dust on the cylinder head, valve or
valve guide.

Lubricate the valve stem and valve guide bore with
clean motor oil.

Install the valve. The assembly shall be completed
according to the original valve indicators.

Note: The intake valves are interchangeable, but

the exhaust valves are not.

Press the valve oil seal and spring seat assembly
into the upper end of the valve guide, apply some
motor oil on the guide opening or the edge of the
valve oil seal and wrap the glove of the valve cotter
by adhesive tape. After the valve is installed, take
away the adhesive tape.

Install the valve spring and valve spring seat,
compress the valve spring seat to the stroke that
enables the valve cotter groove to appear by special
compression device and install the cotter. Then
slowly release the compression device and remove
it.

After the whole valve cotter is installed, put the
cylinder head on a piece of wood and knock at the
small end of the valve stem by a plastic or copper
hammer to help the valve mechanism to be in place
better.

Size of intake valve seat ring and cylinder head
seat ring bore

Class

Diameter of

intake

valve seat

ring (unit:

mm)

Diameter of

the seat ring

bore of

cylinder

head (mm)

Interfer

ence

(mm)

Standard

43.877

01

.

0

01

.

0

+

−

43.763

025

.

0

0

+

Oversized

0.5

44.377

01

.

0

01

.

0

+

−

44.263

025

.

0

0

+

Oversized

1.0

44.877

01

.

0

01

.

0

+

−

44.763

025

.

0

0

+

0.079

—

0.124

Size of exhaust valve seat ring and cylinder head seat ring bore

Class

Diameter of exhaust valve

seat ring (mm)

Diameter of cylinder head

seat ring bore (mm)

Interference

(mm)

Standard

38.877

01

.

0

01

.

0

+

−

38.263

025

.

0

0

+

Oversized

0.5

39.377

01

.

0

01

.

0

+

−

38.763

025

.

0

0

+

Oversized

1.0

39.877

01

.

0

01

.

0

+

−

39.263

025

.

0

0

+

0.079—0.124

UAES’s

new

two-valve

38.377

01

.

0

01

.

0

+

−

38.263

025

.

0

0

+

Oversized

0.5

38.877

01

.

0

01

.

0

+

−

38.763

025

.

0

0

+

Oversized

1.0

39.377

01

.

0

01

.

0

+

−

39.263

025

.

0

0

+

0.079—0.124

Size of valve guide and valve guide bore

Class

Valve guide bore

(unit: mm)

Diameter of cylinder head

guide hole (unit: mm)

Interference

(unit: mm)

Standard

13.555

0

01

.

0

−

13.481—13.519

Oversized

14.305

0

01

.

0

−

14.231—14.269

Oversized

14.505

0

01

.

0

−

14.481—14.519

0.026—0.07

COMPRESSION PRESSURE

COMPRESSION INSPECTION

Warning

·Hot engines and oil can cause severe burns. Be careful not to burn yourself during

removal/installation of each component.

1. Verify that the battery is fully charged.

·Recharge it if necessary.

2. Warm up the engine to the normal operating temperature.

3. Stop the engine and allow it to cool off for about 10 min.

4. Perform “Fuel Line Safety Procedures”. Leave the fuel pump relay removed.

Warning

·Fuel vapor is hazardous. It can very easily ignite, causing serious injury and damage.

Always keep sparks and flames away from fuel.

·Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries

or death and damage. Fuel can also irritate skin and eyes. To prevent this, always
complete the “Fuel Line Safety Procedure”.

5. Remove the ignition coil connector.

6. Remove the spark plugs.

7. Connect a compression gauge into the spark plug

hole.

8. Fully depress the accelerator pedal and crank the

engine.

9. Note the maximum gauge reading.

10. Inspect each cylinder as above.

·If the measured value is less than the limited value, or there is a cylinder whose

compression value varies from that of other cylinders, add a small amount of engine oil
through the spark plug hole. Then measure the compression pressure and perform the
respective operations for the following cases.

— If the compression increases, the piston, the piston rings, or cylinder wall may be worn

and overhaul is required.

— If the compression stays low, a valve may be stuck or improperly seated and overhaul is

required.

— If the compression in adjacent cylinders stays low, the cylinder head gasket may be

damaged or the cylinder head distorted and overhaul is required.

Cylinder Pressure Standard Value：1.00-1.35 Mpa (10-13.5 kgf/cm2)

11. Disconnect the compression gauge.

12. Install the spark plugs.

13. Connect the ignition coil connector.

14. Install the fuel pump relay.