Contents: Examination ↓ Cylinder repair ↓
Examination
The cylinder block is thoroughly washed and the oil channels are cleaned. After blowing and drying with compressed air, the cylinder block is inspected. Cracks in any places of the cylinder block are not allowed.
If there is a suspicion of coolant getting into the crankcase, the cylinder block is checked for leaks on a special stand. To do this, having plugged the openings of the cooling jacket of the cylinder block, water at room temperature is pumped into it under a pressure of 3 kgf/cm². No water leakage from the cylinder block should be observed within 2 minutes.
If oil is observed getting into the coolant, then without completely disassembling the engine, check for cracks in the cylinder block in the oil channel areas. To do this, drain the coolant from the cooling system, remove the cylinder head, fill the cooling jacket of the cylinder block with water and. supply compressed air to the vertical oil channel of the cylinder block. If air bubbles appear in the cooling jacket, replace the cylinder block.
Check the plane of the cylinder block joint with the head using a ruler and a set of feeler gauges. The ruler is installed along the diagonals of the plane and in the middle in the longitudinal direction and across. If the non-flatness exceeds 0.1 mm, the cylinder block is replaced.
Cylinder repair
They check whether the cylinder wear exceeds the maximum permissible value of 0.15 mm. The cylinder diameter is measured with a bore gauge in four zones both in the longitudinal and transverse directions of the engine (figure 43). The A.96137 caliber is used to set the bore gauge to zero. In the belt/cylinder area, there is virtually no wear. Therefore, the difference in measurements in the first and other belts can be used to judge the wear of the cylinders.
The source is on the website: VAZBOOK
Figure 43. Cylinder measurement diagram: A and B are the directions of measurements; I-IV — belt numbers
If the maximum wear of the cylinders is in the belt zone II (maximum wear zone) exceeds 0.15 mm or the gap between the piston and the cylinder in the area of belts III and IV exceeds 0.15 mm, then the cylinders are bored to the nearest repair size, leaving an allowance of 0.03 mm on the diameter for honing. Then the cylinders are honed, maintaining such a diameter that when installing the selected repair piston, the gap between it and the cylinder is 0.025-0.045 mm.