Pistons produced by regular manufacturers are generally cast with eutectic aluminum-silicon alloy
The hardness of the aluminum piston is greater than 100HB (Brinell hardness value), and the tensile strength reaches above 2450MPa. The content of silicon in the eutectic aluminum-silicon alloy composition in high-quality pistons can reach 13%. Due to the small thermal variability of silicon, it has excellent thermal stability at high temperatures, but the content of silicon in the piston material is high. The manufacturing process requirements are relatively high.
In order to reduce production costs, some unscrupulous enterprises use recycled waste aluminum alloy pistons for casting. The silicon content in the materials of such fake and inferior pistons is very small. If it is installed in the engine, because of its large thermal variability, as long as the engine temperature rises, the thermal expansion will inevitably be too large, and the piston skirt will rub against the cylinder wall violently, resulting in cylinder swelling, engine weakness and power drop failures.
Easy to identify the pros and cons:
First is to observe from the back of the piston (the opposite side corresponding to the top), the back of the piston with high silicon content is darker in color, and the inner side has a very clear manufacturer's logo. However, the silicon content of fake and inferior pistons is extremely low, and the color of the back of the piston is whitish (pure aluminum white);
Second is that the pistons produced by regular manufacturers have high density, and their proportion is larger than that of fake and inferior pistons. Therefore, the easiest way to identify it is to put the accessory piston and the piston produced by the regular manufacturer (must be the same model, same displacement, and basically the same size) on an electronic scale, and you will see the difference.
