Engine 2.0 (Chery Fora, A21). Manual — part 10

CHERY A21 SERVICE MANUAL

MECHANISM OF 2.0NALC ENGINE

37

4)

Inspect the diameter of piston pin and
piston pin hole.

a. As the following picture, measure the

piston pin position around with
micrometer caliper. And take the
maximum value as the diameter of
piston pin.

b. Measure the diameter of piston pin hole

around with micrometer guage for
inside diameter, as the following picture,
and take the minimum value as the
diameter of pin hole.

Replace with the new piston and pin if the
examined clearance exceeds the limit.

Standard

Size

Diameter of piston pin

21

0

005

.

0

−

Diameter of piston pin

hole

21

008

.

0

002

.

0

CHERY A21 SERVICE MANUAL

MECHANISM OF 2.0NALC ENGINE

38

5)

Inspect the connecting rod journal and
connecting rod bearing

a.

Examine the diameter of connecting rod
journal.

Measure the axle diameter of connecting rod
with micrometer caliper.

Rotate the crankshaft 90° and measure it
again.

Work out the Roundness and cylindricity
through twice measuring.

①

Roundness=Max. diameter

— Min.

diameter /2 as the picture, take the
vertical diameters on the same plane,
subtract the half of Minimum from the
Maximum to get roundness.

②

cylindricity= Maximum bore

－

Minimum bore/2 As the picture,
measure the bores of 3 planes along
both A direction and B direction
respectively. Get the maximum and the
minimum from 6 values, and then
subtract the half of Minimum from the
Maximum to get cylindricity;

b.

Inspect the radial clearance of
connecting rod bearing

Inspect the radial clearance of connecting rod
bearing with clearance gauge. Clean up the
connecting rod journal and connecting rod
bearing. And put clearance gauge on the
journal, fasten bearing bushing and fasten the
bolt according to set torque.

Standard

Value

Diameter

9

.

47

0

016

.

0

−

Roundness

——

Cylindricity

——

CHERY A21 SERVICE MANUAL

MECHANISM OF 2.0NALC ENGINE

39

Note: Do not rotate the crankshaft during the
process.

CHERY A21 SERVICE MANUAL

MECHANISM OF 2.0NALC ENGINE

40

Loosen the connecting rod bolt, remove the
cap, and measure the maximum width of
pressed clearance gauge with the ruler on its
package to get the clearance value.

Replace with the new connecting rod bearing
if the examined clearance exceeds the limit.

Note: Use the same brand consistent with
assorting sign when you replace the bearing
bushing.

Standard

Value

Abrasion

Limit

Clearance 0.016—0.051

Selection of connecting rod bearing:

You may select the connecting rod bearing by
observing the sign on the first balance weight

at the front end of crankshaft.

（see picture,

unavailable

）

6)

Inspect the planeness of cylinder block
surface.

a:

Clean the upper surface of cylinder
block.

b:

Check with ruler and feeler gauge
whether the surface of cylinder block is
warped. (Measure it in the sequence of
A, C, D, E, F, G in the picture)

C:

Revise it if the warping amount is
excessive.

Replace with the new cylinder if it exceeds
the limit. The maximum for the sum of
permitted abrading thickness of cylinder
block and cylinder head is:

Standard

Value

limit

value

warping

amount

0.04

Clearance Gauge of Plastic