Chery S11 / Chery QQ. Manual — part 120

Chery QQ Service Manual

Mechanical Part of SQR 472Engine

49

5.4 Assemble the piston and connecting rod assembly,

connecting rod bearing bushing and the connecting rod

bearing cap, pay attention to the following:

5.4.1

The opening of compression ring and the

opening of oil ring should be in the specified direction.

5.4.2

The bolts of the connecting rod should be

covered with nylon sleeves for fear of scraping the

cylinder body and the axle.

5.4.3

The surfaces of piston and connecting rod and

other surfaces where relative motion exists should be

spread with engine oil.

5.4.4

Confirm the mark forwards of the piston and

strike it into the cylinder body with the piston ring striking

tool.

Notice: The cylinder number of the piston and

connecting rod assembly should be in accordance with the

cylinder number.

5.4.5

Assemble the connecting rod bearing cap and the

connecting rod bushing, pay attention to the following:

5.4.5.1

Put the cover on the bolt as per the mark

forwards, spread a little engine oil over the joint surface

between the nut and its seat.

5.4.5.2 Tighten the right nut and the left nut alternatively

for several times with specified torque.

Torque: 40±2N.m

Notice: The connecting rod and the connecting rod

bushing should be of the same subassembly:

.

Forward Mark

Chery QQ Service Manual

Mechanical Part of SQR 472Engine

50

Chapter 3. Table of Main Fit Clearance for SQR472 Engine SQR472

1

Clearance between Cylinder Hole and Piston Skirt (Piston to Cylinder Clearance)

Name of Component

Size and Tolerance

Clearance or Value of

Interferenc

Remark

Cylinder hole

φ72

01

.

0

0

+

Group X:

72

0.005

0

F

Group S:

72

0.01

0.005

F

Piston skirt

φ72

015

.

0

025

.

0

-
-

Divided into two groups:

Clearance for group X:

0.019mm～0.03mm

Clearance of group S:

0.018mm～0.029mm

2

Clearance of Crankshaft Main Bearing

Name of Component

Size and Tolerance

Clearance or Value of

Interferenc

Remark

Crankshaft main journal

φ42h

6–0

。

016

Bearing bushing

2

0

0.006

-

Bore of cylinder main bearing φ46F

6

041

.

0

025

.

0

+
+

Clearance 0.025~0.069

3

Clearance of Crankshaft Connecting Rod Bearing

Name of Component

Size and Tolerance

Clearance or Value of

Interferenc

Remark

Crankshaft connecting rod

journal

φ37h

6

0

016

.

0

-

Bearing bushing

1.5

0

006

.

0

-

Bore of connecting rodbig

end bearing

φ40F

6

041

.

0

025

.

0

+
+

Clearance 0.025~0.069

4

Clearance between Piston Pin and Piston Pin Hole

Name of Component

Size and Tolerance

Clearance or Value of

Interferenc

Remark

Piston Pin Hole

φ18

007

.

0

002

.

0

+
+

Piston pin

φ18

001

.

0

004

.

0

-
-

Divided into twogroups

Clearance for group A:

0.004 mm～0.0085mm；

Clearance for group B:

0.0045mm～0.009 mm

Notice: When installed

with hand, the piston pin

may pass through the

piston pin hole smoothly

without

any

obvious

obstruction, otherwise the

piston

pin

should

be

replaced.

5

Inteference between Piston and Small End of Connecting Rod

Name of Component

Size and Tolerance

Clearance or Value of

Interferenc

Remark

Connecting rod small end

hole

φ18

026

.

0

044

.

0

-
-

Value of Interferenc

0.021~0.043

Chery QQ Service Manual

Mechanical Part of SQR 472Engine

51

Piston Pin

φ18

001

.

0

005

.

0

-
-

6

Fit Clearance between Connecting Rod Body Hole and Bolt Bar

Name of Component

Size and Tolerance

Clearance or Value of

Interferenc

Remark

Connecting rod body hole

φ8.08 H

7

015

.

0

0

+

The hole should be processed along

with the connecting rod body.

Bolt Bar

φ8.08 S

6

032

.

0

023

.

0

+
+

Value of Interferenc

0.008~0.032

7

Fit Clearance between Connecting Rod Cover Hole and Bolt Bar

Name of Component

Size and Tolerance

Clearance or Value of

Interferenc

Remark

Connecting rod cover hole

φ8.08 H

7

015

.

0

0

+

The hole should be processed along

with the connecting rod body.

Bolt bar

φ8.08 f

6

005

.

0

014

.

0

-
-

Clearance

0.005~0.029

8

Radial Clearance of Camshaft Bearing

Name of Component

Size and Tolerance

Clearance or Value of

Interferenc

Remark

Cylinder Head

φ26H

7

021

.

0
0

1

st

bearing cap

Camshaft

φ26f

6

020

.

0

033

.

0

-
-

Clearance

0.020~0.054

1

st

bearing cap

Cylinder Head

φ23H

7

021

.

0
0

2

nd

, 3

rd

, 4

th

& 5

th

bearing caps

Intake

Camshaft

φ23f

6

020

.

0

033

.

0

-
-

Clearance

0.020~0.054

2

nd

, 3

rd

, 4

th

& 5

th

bearing caps

Cylinder Head

φ29H

7

021

.

0
0

1

st

bearing cap

Camshaft

φ29f

6

020

.

0

033

.

0

-
-

Clearance

0.020~0.054

1

st

bearing cap

Cylinder Head

φ23H

7

021

.

0
0

2

nd

, 3

rd

, 4

th

& 5

th

bearing caps

Exhaust

Camshaft

φ23f

6

020

.

0

033

.

0

-
-

Clearance

0.020~0.054

2

nd

, 3

rd

, 4

th

& 5

th

bearing caps

9

Fit Clearance between Tappet Hole and Tappet

Name of Component

Size and Tolerance

Clearance or Value of

Interferenc

Remark

Cylinder Head Hole

φ28H

7

021

.

0
0

Tappet

φ28f

6

020

.

0

033

.

0

-
-

Clearance

0.020~0.054

Chery QQ Service Manual

Mechanical Part of SQR 472Engine

52

Remarks: In the above tables, the capital letter and suffix following the sizes (For example, H

7

of φ28H

7

) mean the

process precision, which are unconcerned with the maintenance and may be ignored in the course of maintenance.

Chapter 4. Table

of

Measurement

Parameters

of

SQR472

EngineSQR472

No.

Measuring Items

Acceptance value

Remark

1

Axial clearance of crankshaft

0.089-0.211mm

Assemble the crankshaft and tighten the

main bearing cap bolt

≤1 Nm

Mount the piston connecting rod

assembly and tighten the connecting

rod bolt

≤5.5Nm

≤6Nm

Torque of crankshaft

when rotating at

uniform speed

Installing timing belt and spark plug

≤

26 Nm

2

Mount the valve, spring and camshaft (excluding timing belt

and spark plug) on the cyllinder head, tighten the camshaft

bolt, and then measure the torque of the camshaft rotating at

uniform speed

≤32 Nm

3

Distance between the outer edge of steel ball and the front end

of camshaft

5.65±0.5mm

4

Distance between the outer edge of steel ball and the rear end

of camshaft

8.65±0.5mm

5

Axial clearance of intake camshaft

0.10~0.179

6

Axial clearance of exhaust camshaft

0.10~0.253

7

Jumping amount of installation surface of flywheel wearing

piece

0.10mm

max

8

Protrusion height of crankshaft woodruff key

2～2.20mm

9

Intake valve clearance

0.18±0.05mm

10

Exhaust valve clearance

0.25±0.05mm

11

Tension of timing belt (When the middle part of the rigth side

is pressed down for 4-5mm）

200～280N.m

12

Compression pressure of cylinder

10~14bar

13

Tension of generator belt （ When the part between the

generator and water pump is pressed down for 4-5mm）

98N.m

14

Refilling amount of engine oil (including filter)

3.5 Liter