Maximum allowable wear of main mating engine parts

The wear parts are paired mainly with replaceable parts, which allows you to repair the cylinder block by regrinding or replacing liners, replacing worn camshaft bushings with semi-finished ones and then processing them to the required size, replacing crankshaft main bearing shells.

Restoring the performance of a pair of cylinder block bore - pusher due to their slight wear comes down to replacing the pushers.

Repair and replacement of cylinder liners

Cylinder block puller

Fig. 1. Puller for pressing out the liner from the cylinder block: 1 - puller; 2 - sleeve; 3 - cylinder block

The maximum allowable wear of cylinder liners should be considered as an increase in the gap between the sleeve and the piston skirt up to 0.3 mm.

If there is such wear, press the liner out of the cylinder block using a puller 1 (Fig. 1) and bore it to the nearest piston repair size with a machining tolerance of +0.06 mm.

Do not clamp the sleeve into the jaw chuck during processing, as this will deform the sleeve and distort its dimensions.

Fix the sleeve in the device, which is a sleeve with seat belts with a diameter of 100 and 108 mm.

Insert the sleeve into the bushing until it stops against the upper collar, which is clamped with the overlay ring in the axial direction.

After processing, the liner cylinder mirror should have the following deviations:

1. Ovality and taper not more than 0.01 mm, and the larger base of the cone should be located in the lower part of the sleeve.

2. Barrel and corset - no more than 0.08 mm.

3. The beating of the cylinder mirror relative to the landing belts with a diameter of 100 and 108 mm is not more than 0.01 mm.

Measuring the case protrusion above the block plane

Fig. 2. Measurement of the protrusion of the sleeve above the plane of the block

After pressing the liner into the cylinder block, check the protrusion of the upper end of the liner above the upper plane of the block (Fig. 2).

Protrusion should be 0.005-0.055 mm. If the protrusion is insufficient (less than 0.005 mm), the head gasket may be pierced; in addition, coolant will inevitably enter the combustion chamber due to insufficient sealing of the upper belt of the liner with the cylinder block.

When checking the protrusion of the end of the sleeve above the block, it is necessary to remove the rubber sealing ring from the sleeve.

Case Clamp

Fig. 3. Clamp for sleeves: 1 - nut; 2 - washer; 3 - sleeve

To prevent the liners from falling out of their sockets in the block during repairs, secure them with washers 2 and bushings 3, put on the cylinder head mounting studs, as shown in fig. 3.

Cylinder liners bored out to the third oversize of the piston, after wear, replace with new ones.

Related parts

Ultimately

admissible,

mm

Place and method of measurement

gaps

ellipse

and taper

Cylinder - piston

0,3

Measure the cylinder in two mutually

perpendicular

directions

(along the axis of the crankshaft

and perpendicular to it)

and two belts

(at a distance of 8-10 mm and 60-65 mm)

from the top of the block.

Take the largest size.

Measure the piston at a distance of 5-10 mm

from the bottom of the skirt in the plane,

perpendicular to the axis of the piston pin

Main and connecting rod journals

crankshaft - liners

0,15

Measure as indicated in the article

"Repair of the crankshaft UAZ-3151"

Crankshaft journal

0,07

Along the axis of the crankshaft

and perpendicular to it

Crankshaft journal

0,05

Too

Axial clearance of the crankshaft

0,25

Measure with a probe in several

places around the circumference

Camshaft axial clearance

0,25

Too

Axial clearance of connecting rod

0,5

Too

Cylinder block - pusher

0.1

Measure in two belts

on the length of the working surface

Valve - guide sleeve

0.25

Too

Camshaft journal - sleeve

0.15

Camshaft journal

0.05

Piston pin - bushing top

connecting rod heads

0,10

Measure in two belts

on the length of the working surface

Piston pin - piston

0,10

Too

Connecting rod bushing

0,02

Measure along the axis of the connecting rod

and perpendicular to it

piston pin

0,01

Too

Piston ring - groove in

piston (height)

0,15

Measure with a probe in several

points around the circle

Piston ring - gap in the lock

3,0

Table: Dimensional groups of pistons

Designation

dimensional

groups

Limit deviations

skirt diameter, mm

А

0,000

-0,012

Б

+0,012

0,000

В

+0,024

+0,012

Г

+0,036

+0,024

Д

+0,048

+0,036