Where are cracks most likely to be found when inspecting a piston?

When inspecting a piston, cracks are most likely to be found at the base of the piston bosses and bore junction due to the significant mechanical and thermal stresses experienced in this area. The piston bosses are the thickened areas that provide support for the connecting rod, and the junction with the piston bore is where forces are concentrated during operation.

As the piston moves up and down in the cylinder, it undergoes repeated thermal expansion and contraction, coupled with significant pressure and loads during combustion. These factors create a higher likelihood of crack formation at this specific site as the material may weaken over time due to thermal fatigue or mechanical stress.

In contrast, while cracks can technically occur anywhere on a piston, areas like the piston ring lands and walls, the outer surface of the piston, and near the connecting rod attachment are generally not as prone to cracking under normal operating conditions compared to the base and bore junction. The unique combination of stresses and strains at the base of the piston bosses makes it the most critical area to inspect for potential cracks.