Why is there a difference in temperatures between intake and exhaust valves?

The difference in temperatures between intake and exhaust valves primarily arises from their distinct roles in the combustion process. Intake valves are exposed to cooler air-fuel mixtures entering the combustion chamber, while exhaust valves endure high temperatures from burnt gases exiting the chamber. Additionally, the exhaust valves face more thermal stress and heat transfer due to the combustion process, leading to higher temperatures. This temperature disparity is critical for valve material selection and engine performance optimization.