The design of the cylinder block

The cylinder block is made by casting from special high-strength cast iron. The holes for the cylinders are bored directly into the block. To obtain a high degree of accuracy and surface finish, the cylinders are honed. According to the diameter, the cylinders are divided into 5 classes through 0.01 mm (see table. 1), denoted by Latin letters A, B, C, D and E. The class of each cylinder is marked on the lower plane of the cylinder block.

The holes for the main bearings of the crankshaft are bored together with the bearing caps. Therefore, they are not interchangeable either with each other or with the covers of other cylinder blocks, and in order not to confuse the covers, they are marked (see fig. 65). Bearing caps are attached to the cylinder block with self-locking bolts, the replacement of which with any other is unacceptable.

The accessory drive shaft rotates in two bushings pressed into the cylinder block. The front hub is steel-aluminum, and the rear one is metal-ceramic. Spare parts are supplied with bushings of nominal and repair sizes with an inner diameter reduced by 0.3 mm.

Attention. Cylinder blocks of various engine models are not interchangeable. They can be identified by the model number molded on the left side of the cylinder block.