Mudflap wrote: ↑
Mon Nov 06, 2017 10:31 pm
There are very good reasons why there's no pneumatic valves in road cars yet.
Seals wear fast, they need a pneumatic bottle and/or a compressor, the oil purge system is a black art, valve rotation is very poor and highish lift, large included angle valves can drop and lock when pressure is lost (as in when the car has sat for a while).
Ah yeah and calculating the required pressure is another pain - too high and the they eat up more power than a spring, too low and they float.
The seal problem is solvable using available parts. Pneumatic bottle / Tank is obvious.
As far as the rest - if I ever did pursue such a project I would develop the valvetrain using FEA and then test on a Spintron. But that's a big if, I doubt I'll ever have the time to be honest.
Besides when I say "street car" I'm not talking about a vehicle that lasts 250,000 miles I'm talking about one of my project cars that typically see less than 10,000 miles between rebuilds.