Vaz 21213, Руководство по ремонту, Страница: 23 / 222

Table 2-1
Connecting rod classification as to
small-end and big-end weights
Connecting rod weight, g Class Paint mark
small-end big-end
519±3 Ä white
186±2 525±3 Ç blue
531±3 ë red
519±3 D black
190±2 525±3 E violet
531±3 F green
519±3 G yellow
194±2 525±3 ç brown
531±3 I orange
Selecting piston to cylinder
The design clearance between the piston and cylinder bore
(for new parts) is 0.025 - 0.045. The condition must be ensured
through prior measurements of the associated parts and fitting of
the pistons which belong to the same class of cylinders. The max-
imum permissible gap (for worn parts) is 0.15 mm.
When the engine, in the course of operation, shows a clear-
ance of over 0.15 mm, reselect the pistons to the cylinders to
have the clearance as close to the design value as possible.
The pistons of classes Ä, ë, Ö are intended for replacement.
These classes can be selected to closely match any cylinder in
the event of the engine overhaul, since the pistons and cylinders
are classified with small overlapping in the sizes. It means, the
piston of class C can match the cylinders of class B and D.
Dismantling and reassembly
Dismantling. Prise out the gudgeon pin circlips from the pis-
ton, press out the gudgeon pin and detach the connecting rod
from the piston. Remove the piston rings.
The bolts are pressed into the connecting rod and must never
be pressed out from the connecting rods during the engine or pis-
ton/connecting rod dismantling.
When some components of the piston or connecting rod are
not damaged or show little wear, they can be re-used. Identify
them accordingly during dismantling to facilitate further reassem-
bly with the respective components and to the original cylinder.
Reassembly. Before reassembly, select the gudgeon pin to
match the piston and connecting rod. For new components the
class of the holes for the gudgeon pin in the connecting rod and
pistons must be identical to the class of the gudgeon pin. In case
of used components, for perfect mating, the gudgeon pin when
oiled should fit the relevant piston hole by force of the hand thumb
(Fig.2-32); it should not drop out while held as shown in Fig.2-33.
If the gudgeon pin drops, replace it with a new one of the next
class. When the piston is fitted with the gudgeon pin of the third
class, renew the piston, gudgeon pin and connecting rod.
The reassembly of the piston and connecting rod is a rever-
sal of dismantling. After reassembly oil the gudgeon pin through
the holes in the piston bosses. Refit the piston rings in the order
as detailed below.
Oil the piston rings and grooves in the piston. Arrange the pis-
ton rings so that the gap of the first compression ring is at a 45°
interval to the gudgeon pin; space the gap of the second com-
pression ring at about 180° interval to the first compression gap,
afterwards align the gap of the oil ring at about 90° interval to the
first compression ring gap.
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Fig.2-32. Fitting the gudgeon pin using the thumb pressure Fig.2-33. Checking the gudgeon pin fitting