How to Identify Engine Piston Slap?

[AmirFitz]

The method to identify engine piston slap is that after the fault occurs, a clear metallic knocking sound will be emitted from the cylinder. The sound changes with the engine temperature - it's more noticeable when the engine is cold, and weakens or disappears as the temperature rises. Here are the reasons for engine piston slap: 1. Excessive clearance between piston and cylinder. Improper repair leads to excessive clearance, causing severe knocking noise. When the engine warms up, the piston expands, reducing the clearance and thus diminishing or eliminating the knocking sound. 2. Incorrect piston installation direction or piston deformation, which disrupts the normal clearance between piston and cylinder, resulting in piston slap noise.