Cylinder liners in aluminium engine blocks — common material choice In modern aluminium cylinder blocks, which material is typically used for the cylinder liners to provide wear resistance and durability?

Introduction / Context:
Aluminium blocks are valued for low mass and thermal conductivity, but aluminium alone lacks the wear resistance required for piston–ring contact surfaces. Liners or surface treatments are used to ensure longevity.

Given Data / Assumptions:

• Conventional aluminium blocks with replaceable liners.
• Focus on typical material selection, not specialised coatings like Nikasil or plasma spraying.

Concept / Approach:
Cast iron liners offer excellent scuff resistance, good compatibility with common ring materials, and adequate thermal stability. They are widely used as dry or wet liners in aluminium blocks for passenger vehicles.

Step-by-Step Solution:
Identify performance needs: wear resistance, machinability, cost.Cast iron meets these needs better than aluminium, brass, or bulk ceramics for mainstream engines.Therefore, select cast iron.

Verification / Alternative check:
Manufacturer literature and engine rebuild practices commonly reference grey or alloyed cast iron liners in aluminium blocks.

Why Other Options Are Wrong:

• Aluminium: insufficient wear resistance at the bore without coatings.
• Ceramic: excellent hardness but impractical and costly as full liners.
• Brass: poor wear properties for cylinder bores.

Common Pitfalls:
Assuming the block bore material equals the liner; many modern designs use inserted liners or advanced coatings instead.

Final Answer:
cast iron