After the engine has been disassembled, it is necessary to thoroughly wash all the parts with gasoline and remove carbon deposits.

Before assembling the engine, it is necessary to design the cylinder block, cylinder head and all the main parts for assembling the engine.

Check the tightness of the cooling jacket of the unit, to do this, plug all the holes in the block with wooden plugs, except for one, to which a compressed air hose is connected.

Lower the unit into a bath of water and apply compressed air at a pressure of 1.5 atm.

In places of leakage, air bubbles will come out.

In the same way, check the tightness of the oil channels of the unit.

If a leak is detected, the unit must be replaced.

Дефектовка деталей двигателя ВАЗ-2123

The main dimensions of the cylinder block of the VAZ-2123 engine

Дефектовка деталей двигателя ВАЗ-2123

Marking of the cylinder size class on the block

Дефектовка деталей двигателя ВАЗ-2123

We measure the diameter of the cylinders with a nutrometer in four belts (at a distance of 8, 15, 50, 90 mm from the upper plane of the block) and in two directions (parallel and perpendicular to the axis of the crankshaft).

If the wear exceeds 0.15 mm, it is necessary to drain the block to the repair size by 0.4 or 0.8 mm.

Дефектовка деталей двигателя ВАЗ-2123

The scheme of measuring cylinders with a nutrometer

Дефектовка деталей двигателя ВАЗ-2123

In zone 1, the cylinders practically do not wear out. By the difference of measurements in the first and other belts, it is possible to judge the amount of cylinder wear

Дефектовка деталей двигателя ВАЗ-2123

To determine the wear of the piston skirt, we measure the diameter with a micrometer in a plane perpendicular to the axis of the piston pin, at a distance of 55 mm from the bottom of the piston.

Дефектовка деталей двигателя ВАЗ-2123

We measure the diameters of the connecting rod necks of the crankshaft with a micrometer

Дефектовка деталей двигателя ВАЗ-2123

We measure the diameters of the main necks of the crankshaft

The crankshaft necks are ground to the nearest repair size if their ovality is greater than 0.03 mm, as well as if there are bullies and risks on the necks.

Дефектовка деталей двигателя ВАЗ-2123

After grinding, it is necessary to remove the plugs from the oil channels and remove the remnants of abrasive and deposits. Installing new plugs

The flywheel surfaces mated to the crankshaft and to the driven clutch disc must be scratch-free, scuffed and completely flat.

Дефектовка деталей двигателя ВАЗ-2123

If there are scratches on the working surface of the 3 flywheels under the driven clutch disc, then it is necessary to cut through this surface, removing a layer of metal with a thickness of no more than 1 mm.

Then cut the surface 2, maintaining a size of 0.5 ± 0.1 mm and ensuring the parallelism of surfaces 2 and 3 relative to surface 1.

The tolerance of non-parallelism is 0.1 mm.

After threading, we install the flywheel on the mandrel, centering it along the landing hole with an emphasis on the surface 1, check the runout of planes 3 and 2.

At the extreme points, the indicator should not show beats exceeding 0.1 mm.

We pay attention to the density of the landing of the toothed crown and the condition of its teeth.

If the crown can be moved on the flywheel or the teeth are badly worn, replace the flywheel assembly with the crown.

Replacing the crown is quite complicated and requires certain skills from the performer, as well as the use of a special tool.

Дефектовка деталей двигателя ВАЗ-2123

We install the flywheel and the removed components and parts in the reverse order of removal.

The flywheel can be mounted on the crankshaft in two opposite positions, determined by the location of the mounting holes.

At the factory, it is balanced in assembly with the crankshaft, so it must be installed strictly in its original position.

For proper installation, a mark in the form of a conical hole is made on the flywheel, which must be oriented when installed in the same direction as the connecting rod neck of the 4th (1st) cylinder.

If, after removing the flywheel, the crankshaft was rotated, set the piston of the 4th cylinder to the TDC position of the compression stroke, then another half turn and install the flywheel on the crankshaft by turning it vertically downwards.

Tighten the flywheel mounting bolts evenly crosswise with a torque of - 60.96-87.42 Nm (6.22-8.92 kgf.m)

The defect of other components and parts of the VAZ-2123 engine will be considered in articles on these nodes.