The 8FC piston can be divided into three parts, top, head and skirt.
The top of the 8FC piston is mainly used to process the combustion chamber and reserve a certain space for the valve, and its shape is related to the shape of the combustion chamber and the compression ratio. At present, most gasoline engines use flat-top pistons, which are simple to process and have a small heating area. For gasoline engines that want to adjust the compression ratio, concave or convex pistons can be appropriately used. For diesel engines, in order to better promote combustion and form a secondary turbine, the piston top is usually made into a specific shape.

The part between the top of the 8FC piston and the lower end face of the oil ring groove is called the piston head. It has four functions. First, a piston ring groove is machined on it to install the piston ring; secondly, it seals the cylinder together with the piston ring to prevent the combustible mixture from entering the crankcase; thirdly, it can absorb the heat from the top , and transmit heat to the cylinder wall; finally, it can withstand gas pressure and transmit power to the connecting rod.

Generally speaking, the current gasoline engine uses three 8FC piston rings, the first two are the gas rings, and the bottom is the oil ring. At the bottom of the oil ring groove, there are also oil return holes or transverse grooves to remove the oil ring from the cylinder. The excess oil scraped off the walls is sent back to the oil pan. Due to the close contact between the piston ring and the cylinder wall, the wear of the piston ring groove is more serious than that of other areas of the piston, so many manufacturers will cast fiber-reinforced alloy rings in the aluminum alloy piston head, and at the same time in the first ring groove or the first two A heat-resistant retainer is embedded in each ring groove to improve the strength and wear resistance of the piston. It is worth noting that the piston rings should be placed at an angle to ensure the tightness of the cylinder.

At the same time, in order to better cool the 8FC piston, some pistons also design a heat insulation groove above the first air ring, which reduces the heat of the first air ring and transfers more heat to the second and third piston rings, making the Heat dissipation is faster.