What is a 12 valve?

A 12-valve engine refers to an internal combustion engine that has a total of 12 valves, typically consisting of 6 intake valves and 6 exhaust valves. This configuration is common in some diesel engines and older gasoline engines, where each cylinder generally has two valves. The design allows for improved airflow, enhancing engine performance and efficiency compared to older single-valve configurations. It's often found in vehicles known for their durability and simplicity, such as certain models of Dodge Cummins diesel engines.