Chery QQ6 (S21) / S12LHD. Manual — part 232

5. Use a 19# sleeve to remove the fixing bolt of

crankshaft main bearing cap.

Note:

The surface between cylinder block and bearing cap

is ensured by high precision machining plane, so, do not

use any hard article to scuff this surface.

6. Take off crankshaft rear oil seal assembly, remove

bearing shell cover, and then take off crankshaft

assembly.

II. Overhaul of Crank-Connecting Rod System

1. Detection of crankshaft.

1.1 Detection of crankshaft main journal: use an

outside micrometer to measure main journal of

crankshaft and the normal value should be

46.01mm.

1.2 Detection of connecting rod journal: use an

outside micrometer to measure connecting rod

journal of crankshaft and the normal value should

be 44.485-44.495mm.

1.3 Measurement of main journal clearance: place

a plastic feeler gauge on the crankshaft main

journal, tighten the main bearing shell cover to

specified torque and then loosen it, use the

thickness check list on the plastic feeler gauge to

read the value. The normal value should be:

0.02-0.06mm. Use the same method to measure

connecting rod journal clearance.

1.4 Measurement of crankshaft axial clearance:

tighten the main bearing shell cover to specified

torque and then use a dial gauge to measure the

crankshaft axial clearance. When measuring, push

the crankshaft off the dial gauge first and keep the

dial gauge has certain amount of compression, set

the pointer to zero, and then push the crankshaft to

the adverse direction and the numerical value

fetched from the dial gauge will be the crankshaft

axial clearance. The normal value should be

0.02-0.30mm. If exceeding this scope, replace the

crankshaft thrust sheet or the crankshaft.

2. Detection of piston

2.1 Detection of piston diameter: use an outside

micrometer to measure the piston diameter. When

measuring, remember to measure at the place about

11mm up from lower end of the piston. The normal

value should be φ72.965±0.009.

2.2 The piston pin is of semi-floating type, which

can not be disassembled during maintenance,

because it can not be assembled using common

machining technique after disassembled. If

abnormal noise occurs due to improper piston pin

clearance, replace the piston assembly.

2.3 Measurement of piston ring.

2.3.1 Measurement of piston ring end play: first,

place the piston ring into cylinder.

2.3.2 Push the piston head vertically against the

piston ring in the cylinder and let the piston ring be

on a plane.

2.3.3 Use a feeler gauge to measure the gap

between piston ring ends and the normal value

should be: 0.2mm.

2.3.4 Measurement of piston ring side clearance:

place the removed piston ring into the ring groove

(lean to one side as possible) and then place a

feeler gauge into the other side to measure the

clearance; certain resistance feeling after the feeler

gauge is placed in indicates that the measurement

with feeler gauge will be correct. The normal value

should be 0.03mm. Unit: mm

Contents

First ring

Second ring Third ring

End play

0.2

0.4

/

Side

clearance

0.03

0.03

/

Thickness

1.2

1.6

/

3. Measurement of roundness and cylindricity of

cylinder

3.1 Select appropriate cylinder gauge and outside

micrometer.

3.2 Use a vernier caliper to measure rough

diameter of the cylinder hole.

3.3 Adjust the outside micrometer to the data

measured out by the vernier caliper, select the

splicing pole suitable to the range of the cylinder

gauge, and then set the outside micrometer to zero

according to this data.

3.4 Place the cylinder gauge into the cylinder to

measure; when measuring, the yawing angle of

cylinder gauge should not exceed 15º. Fetch the

maximum numerical value.

3.5 The measuring position of the cylinder gauge

in cylinder is as shown in the figure.

Calculation method for roundness: A-B or a-b

Calculation method for cylindricity: the difference

of maximum diameter subtracting minimum

diameter among A, a, B, and b.

The normal value should be: if roundness or

cylindricity exceeds the range, replace with new

cylinder block or install new cylinder sleeve.

3.6 Measurement of planeness of cylinder block:

use steel rule and feeler gauge to measure

planeness of the cylinder block. If the planeness

exceeds the range, replace the cylinder block.

Upper stop position of piston

Lower stop position of piston