Cylinders — wear check

Theoretically, the new cylinder is perfectly round. The operation of the piston results in wall wear at right angles to the piston pins due to side loading. This wear takes place mainly in this section of the cylinder due to friction against the piston rings.

An indication of cylinder wear can be obtained by removing the cylinder heads while the engine is still in the vehicle. The first signs of wear can be seen when the piston is in the down position in the cylinder and a step can be felt directly near the top of the cylinder where the top piston ring reaches. If there is no such step, then the cylinder wear is negligible and there are no losses due to lack of compression or excessive oil consumption due to wear or damage to the piston rings or pistons.

If you have a special micrometer for measuring the cylinder, measure the diameter of the cylinder in the plane below the edge, and the diameter of the hole in the bottom of the cylinder in the same plane. If the difference is more than 0.076 mm, it is necessary to perform boring. Similarly, a difference of 0.076 mm or more in the cylinder diameter is indicative of out-of-roundness and also necessitates boring.

If any of the cylinders has noticeable scratches or grooves, it also requires reboring. This phenomenon usually indicates damage to the piston or rings. If at least one of the cylinders needs to be bored, it is necessary to perform this operation for all cylinders and install new pistons and piston rings oversized. In cases where the engines have already been bored to the maximum size, there are liners (cartridge cases) cylinders, which can be installed if necessary. In such cases, the assistance of a specialized firm will be required to carry out the regrinding process and related maintenance.