In early 90s Ferrari experimented with an “hybrid” design on a single cylinder engine, sleeve valves for intake and poppet for exhaust. I’ve somewhere an Italian technical magazine that published in late 90s an article written exactly by the man who was leading the experimentation that describes the design, the problems and the results. The research was stopped due to lack of money in that period, but there were still many issues to overcome.
In the same period Ferrari also experimented a desmo design. the issue of valve springs was for them particularly important at the time because of the V12 needing to rev higher than V8 and V10. The choice of 5 valves per cylinder was also partly (some say mainly) related to that, then pneumatic valves solved the problem.
Max seems to not fundamentally crasp how important it is for the companies (teams) to win. He thinks you can all sit down together and have an adult discussion about it. When what all these guys really want to do is "destroy" each other.
That’s why any championship, particularly when manufacturers are involved, should be managed like a dictatorship with a very limited group of people, unrelated with teams, defining the rules and giving then the rulebook to the teams negating the possibility to have a say about it.
Most of people believe that the reason currently F1 rules defines about everything on the design and gives very little freedom is a choice of FIA to reduce costs (that per se is nothing but utopia) while it’s entirely a choice of the manufacturers. No big manufacturer is willing to risk that someone arrives with a new solution that really makes the differences because that would mean not only lose on track, but losing badly by seconds, admit you got it wrong and require years to develop a solution someone else introduced first, a PR nightmare nowadays.
They want the rules to limit the design so that the risk to waste money and time on the wrong direction is minimal and even when you get it wrong, isn’t that much wrong so you are close enough to say “it’s just bad luck, we’re almost there, just couple of tenths” anytime the boss asks why you are spending 500 billion per day to be beaten every other Sunday.
The case of the requirement to use a V10 in late 90s is the best example. Everybody in F1 knew that Toyota was working on a V12 for the debut and they feared that, given the advancement in technological level compared with early 90s, it was potentially the best choice forcing them all to follow that direction. Easy solution, impose the V10.
ACO/Le Mans rules follow the same path with the difference that since there’s (at least, there was for years) a single big manufacturer you have the illusion of the freedom and of the innovation. The truth is that Audi followed the diesel route just because ACO gave them enough help with the rules so that even with a non optimal design the car would have been vastly superior to others anyway. What remains is question : did Audi R10 win because of the choice of diesel engine or in spite of it ? But don’t expect an answer for that, certainly not from Audi PR department, we still don’t have an answer for the similar question about the R8 and GDI.