What is the difference between iron and aluminum engine blocks?

[OAvery]

The differences between iron and aluminum engine blocks are as follows: 1. Cast iron cylinder: It has better wear resistance and durability compared to aluminum cylinders, and its manufacturing cost is relatively lower. However, its disadvantage is that the expansion coefficient differs from that of the aluminum pistons inside. When driving at high speeds for extended periods, causing the engine to overheat, the aluminum pistons expand more than the cast iron cylinder, which can sometimes lead to piston seizure, rendering the vehicle undrivable. Additionally, its heavier weight increases fuel consumption. 2. Aluminum cylinder: It is lighter in weight, and its expansion coefficient matches that of the pistons, almost eliminating the risk of piston seizure. It also has better heat dissipation than cast iron. Although its wear resistance is slightly lower than that of cast iron, the difference is minimal due to the use of aluminum alloy. While the material cost is higher than cast iron, the impact on the overall engine cost is negligible. Moreover, its lighter weight contributes to better fuel efficiency.