UAZ-3151 car repair

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

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.

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.

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.

Table: Dimensional groups of pistons