Conceptual wrote:Why the heck arent these used in modern F1 engines? Other than the tech regs keeping them in 1860's technological era...
As you noted, rotary valves are not permitted in F1.
As for the Coates design in particular, if you study it carefully, you'll find that it has higher friction losses and a lower flow coefficient (ie. port time-area) than a well designed conventional four-valve head of similar dimensions. Also, the combustion chamber shape that results from his rotary valve arrangement is nowhere near as efficient as a conventional four-valve, pent roof, center plug design.
Coates makes a lot of unrealistic claims for his valve design. The reason I know this is that I've studied rotary valves in depth, including his. I have a (expired) patent for a rotary valve design (US patent 5052349) that has much better flow characteristics than the Coates design, as well as a more efficient chamber geometry. However, since Coates had much more money to develop his concept, he has been somewhat successful, and I have not.