Chery Fora (Elara A520). Manual — part 55

CHERY A21 SERVICE MANUAL

MECHANISM OF 2.0NALC ENGINE

23

b:

Use internal micrometer guage to
measure the internal diameter of valve
guide and the measuring point is a
quartering point of guide.

c:

Calculate the difference of measured
value and the clearance.

Replace the valve or the guide if the value
exceeds the limit value.

d:

Examine the contact bandwidth of
valve.

e:

Check the valve seat insert.

Measuring Point

Contact Position (Should be

the Center of Slope)

Edge

Thickness

CHERY A21 SERVICE MANUAL

MECHANISM OF 2.0NALC ENGINE

24

Standard

Value

Outer Diameter

of Valve stem

(mm)

IN

￠5.98±0.008

EX

￠5.96±0.008

Inner Diameter

of Valve guide

(mm)

IN

￠5.4±0.1

EX

￠5.4±0.1

Clearance

(mm)

IN

0.02

EX

0.04

Thickness of

Valve Top

（mm）

IN

0.3±0.15

EX

0.3±0.15

Seal Bandwidth

（mm）

IN 1.158

EX 1.306

CHERY A21 SERVICE MANUAL

MECHANISM OF 2.0NALC ENGINE

25

f:

Examine the protruding capacity of
valve stem.

And Examine the protruding high of valve

stem with vernier caliper.

（See picture）

Standard Value

（mm）

Protruding Capacity

Of Intake Valve

stem

47.5

Protruding Capacity

Of Exhaust Valve

stem

47.5

5)

Examine the axial clearance of camshaft.

Replace the camshaft if the value of axial
clearance exceeds the normal value.

Standard

Value

Intake camshaft

0.015—0.02

Exhaust camshaft

0.015—0.02

Top of Valve Stem

Protruding High of Valve Stem

Seat of Valve Spring

CHERY A21 SERVICE MANUAL

MECHANISM OF 2.0NALC ENGINE

26

6)

Examine the planeness of cylinder

a:

Clear the lower surface of cylinder head.

b:

With the help of ruler and feeler gauge,
check whether the lower surface of
cylinder head is warped.(Measure it in
the sequence of A, C, D, E, F, G in the
picture)

Standard

Value

Cylinder head planeness

0.04