i thought of it myself! i didn't know if anyone had manufactured something like this before, but it seems so obvious. use centrifugal forces to move flywheel weights in a spring-advance mechanism - voila!, variable valve timing. i didn't get so far as designing it, but then i wondered why i had never seen anything like it. VVT systems introduced by the automakers are always so much more complicated, i thought, "why wouldn't this work? it's so simple. too simple?" so, i guess the idea does work. we should get MVP or ipd to make one. would improve the power band on any of our cars.