Great Wall engine 4G64S4M. Manual - part 9

11-30

ENGINE

 CYLINDER HEAD AND VALVE

CYLINDER HEAD AND VALVE

DISASSEMBLY AND ASSEMBLY

78N.m

 thorough

looseness

 20N.m 
 90

+90

1

2

8

9

10

14

17

15

20

5

4

6

13

16

18

7

19

11

3

12

All parts inside should be
coated with enging oil in
assembly

6EN1386

N

N

N

N

N

N

N

B

1.

cylinder head bolts

2.

cylinder head cluster

3.

head gasket

4.

valve lock clamp

5.

upper site of valve spring

6.

valve spring

7.

inlet valve

8.

valve lock clamp

9.

upper site of valve spring

10. valve spring

11. exhaust valve
11. valve oil seal
12. valve spring seat
13. valve spring
14. valve spring seat
15. inlet valve guide
16. exhaust valve guide
17. inlet valve seat
18. exhaust valve seat
19. cylinder head

B

C

B

B

C

C

A

C

A

A

D

Disassembly Procedure

11-31

ENGINE

 CYLINDER HEAD AND VALVE

MB991654

MD998772

9EN0062

9EN0063

MD998774

Notices after Disassembly

The disassembled parts should be sorted as per the cylinder number

and the intake/exhaust parts.

Dismantle of Cylinder head Bolts

(1)

Loosen the bolts of each cylinder heads with SST. The looseness

should be even and gradual.

Dism Dismantle of Valve Lock Clamp

(1)

The dismantled parts such as the valve and spring should be

marked with the cylinder number and signboard of mounting

position and kept well so as to prepare the later reuse in assembly.

Dismantle of Valve Oil Seal

(1)

The valve oil seal must not be reused.

Mount of Valve Oil Seal

(1)

Mount the lower site of valve spring.

(2)

Mount the valve oil on the valve guide with SST tools. Incorrect

mount will lead to leakage.

Notice:

 The valve oil seal must not be reused.

A

A

C

B

11-32

ENGINE

 CYLINDER HEAD AND VALVE

Mount of Valve Lock Clamp

(1)

In case the valve spring is over compressed, it will contact the

bottom of the valve spring and thus damage the valve oil seal.

Mount of Cylinder head Bolts

(1)

When assembling the bolts of cylinder head, the bolt length

should be identified to meet the limit value, otherwise, change the

bolts.

Limit Value (A): 99.4 mm (Max)

(2)

Coat the engine oil on the threaded part of the bolts and on the

gasket.

(3)

Tighten the bolts in the tightening order to the specified torque

with SST (MB991654).

Tightening Moment: 78N.m

(4)

Loosen all parts thoroughly.

(5)

Tighten the bolts with the torque of 20N.m in the tightening

order.

upper site of
spring

valve oil seal

lower site of
spring

identifi cation

6EN0437

MD998772

9EN0062

bolt length

6EN0782

6EN0695

C

D

Mount of Valve Spring

(1)

The valve spring shall be mounted in such way that the spring end

with identification color faces the upper site of the valve spring.

B

11-33

ENGINE

 CYLINDER HEAD AND VALVE

paint marks

6AE0297

90

90

9EN0064

contatc position
(the center of slope)

edge thickness

6EN0542

(6)

Mark a straight line with paint on the heads of cylinder head bolts

and the cylinder head.

(7)

Tighten the cylinder head bolts by 90

in tightening order.

(8)

Tighten the bolts by another 90

, ensuring the paint marks on

the heads of cylinder head bolts and the cylinder head should be

in alignment.

Notice:

If the screwing angle of the bolt is less than 90
, correct

tightening moment cannot be expected. Therefore, sufficient

importance should be attached to whether the screwing

angle is correct when tightening the bolts.

In case the bolts are over tightened, they should be

loosened thoroughly and then re-tighten them from Step (1).

Inspection on Cylinder head

(1)

Inspect the Planeness of the surface of cylinder head with ruler

and feeler.

Standard value: 0.03mm

Limit value: 0.2mm

(2)

The deformation should be corrected by grinding in case it

exceeds the limit value.

Grinding limit value: * 0.2mm

Total grinding amount of the cylinder head with the

cylinder block together.

Height of cylinder head (standard value for the new): 119.9

120.1mm

Valve

(1)

Check whether work faces of valve contact correctly. If not,

polish the valve applied and regrinding it. The contact face of

valve seat should be in consistency with the center of work face

of the valve.

(2)

In case the edge thickness exceeds the limit value, change the valve.

Standard edge thickness value:

Intake value ........................... 1.0 mm

Exhaust value ........................ 1.2 mm

Application limit value:

Intake value ........................... 0.5 mm

Exhaust value ........................ 0.7 mm

(3)

Measure the total valve height, in case it is less than the limit

value, change the valve.

Standard value:

Intake value ........................... 112.30mm

Exhaust Value ........................ 114.11mm

Limit Value:

Intake value ........................... 111.80mm

Exhaust Value ........................ 113.61mm