What issue may occur if valve seats are too narrow?

When valve seats are too narrow, one significant issue that can occur is valve overheating. The valve seat's primary function is to provide a sealing surface for the valve when it is closed, but if the seat is too narrow, it may not adequately dissipate heat away from the valve. Valves operate under high temperatures and pressures, and they need sufficient surface area to transfer that heat to the cylinder head effectively.

Narrow valve seats limit the contact area, which leads to a higher concentration of heat. This concentrated heat can cause the valve material to exceed its maximum operating temperature, leading to potential deformation, warping, or even failure of the valve itself. Consequently, overheating can lead to serious engine performance issues or complete engine failure due to valve damage.

This problem underscores the importance of properly sized valve seats for efficient engine operation and longevity. The other issues mentioned may not occur directly as a result of the valve seats being too narrow or may arise from different engine problems, which is why they do not apply in this context.