Which of the following statements is not true concerning oval shaped pistons?

Oval shaped pistons are typically not designed specifically for optimal airflow in engines. Instead, their unique shape serves to reduce friction and improve engine efficiency under certain conditions. In high-performance applications, the design may contribute to better thermal management and enhance the overall efficiency of the engine, but not mainly for the purpose of airflow optimization.

The other statements reflect true characteristics of oval pistons. They are indeed made to maintain minimal clearance between the piston skirt and the cylinder wall, thus reducing friction and wear. This design can lead to improved engine efficiency, particularly in applications where specific performance characteristics are desired. Additionally, oval pistons are often associated with high-performance engines, where their design can be leveraged to optimize performance in niche scenarios, though they may not be commonly used across all engine types.