1：What is it?
An engine is composed of two main parts: the cylinder block and the cylinder head, which are connected to each other with bolts. Different engines use different materials for these components. The common materials for the cylinder block are cast iron and aluminum alloy.
2：Aluminum Alloy Cylinder Block
Aluminum alloy cylinder blocks are lighter in weight and offer better fuel economy. Aluminum has higher thermal conductivity, resulting in improved heat dissipation. However, compared to cast iron, aluminum alloy is more expensive and is prone to chemical reactions with water generated during combustion, leading to poorer corrosion resistance. Additionally, aluminum alloy has slightly lower strength for the same volume.
3：Cast Iron Cylinder Block
Cast iron cylinder blocks have a higher heat load capacity and greater potential for increasing engine power output. They are less susceptible to chemical reactions and exhibit stronger corrosion resistance. Cast iron cylinder blocks are also more cost-effective compared to aluminum alloy. However, they are heavier, resulting in poorer fuel economy.
4：Additional Reading
In order to reduce the inertia of reciprocating components, improve engine speed and response, pistons are mostly made of aluminum alloy. If the cylinder walls are also made of aluminum, the friction coefficient between aluminum surfaces is higher. Therefore, aluminum cylinder blocks often use cast iron or steel cylinder liners or apply coatings to reduce friction.
