Measuring cylinder diameters (VW Golf 2)

To determine the degree of wear of the cylinder mirror, a bore gauge is required. The diameter is measured in a direction parallel to the crankshaft axis, as well as perpendicularly (figure 71). The diameter is measured at a distance of 10 mm from the upper edge of the cylinder and 10 mm above the lower edge, as well as in the middle section of the cylinder. As a result, it is necessary to obtain the results of 6 measurements for each cylinder. All obtained values should be recorded and compared with the data in the Table of dimensional and installation data (table 3), Cylinders are subject to boring to repair size if at least one cylinder:

• the gap between the cylinder and the piston of the nominal diameter exceeds 0.07 mm;
• ovality (difference in diameters of the same level) exceeds 0.04 mm;
• taper (difference in diameter between the upper and lower sections) exceeds 0.05 mm.

Pistons should be replaced if there is mechanical or thermal damage (melting or burning, cracks, etc.); if the wear of the piston grooves has exceeded the permissible values (see below); if the wear of the piston skirt exceeds 0.04 mm, Since the wear of all pistons is approximately the same, it is advisable to replace the damaged piston in case of mechanical and thermal damage, and in other cases - to replace the entire set of pistons, The dimensions of the repair pistons are given in the Table of dimensional and installation data (table 3).





The required cylinder size for boring is determined by measuring the diameter of a new repair-size piston, as shown in Figure 72, i.e. 10 mm above the lower edge of the piston skirt, perpendicular to the axis of the piston pin hole. From the sum of the piston diameter and the clearance of 0.03 mm, 0.02 mm must be subtracted for honing the cylinder.