Piston rings generally have letters or numbers, with one side facing up, no signs and no specific direction regulations, and oil rings are not divided into positive and negative sides. The opening of the piston ring should be staggered by 120° to prevent the flammable mixture from leaking out of the opening gap of the piston ring when the engine is started, making it difficult to start the engine.

The piston ring of the engine needs a special fixture. When installing, pay attention to the installation sequence of the piston ring. Some engine piston rings use three rings, including two air rings and one oil ring, while others use four rings, including three air rings and one oil ring. But the installation sequence is nothing more than the bottom oil ring, and then install the third air ring - the second air ring - the first air ring (silver white).

There is a marking on the piston and connecting rod, which is mostly the one facing forward (towards the clock). It is important to know that the force point and friction coefficient are different in different directions, so this forward mark must be assembled in the correct direction (all facing the front of the body). But there are also a few special cases, such as the small four-wheel link mark is backward, which should be noted. If you are not familiar with it, it is best to leave it to a professional master.