PlatinumZealot wrote: ↑20 Feb 2018, 23:49
It is probably safer to control swirl by making one intake valve slightly smaller, because I am thinking that making one intake valve open slightly quicker than the other one can lead to problems on the exhaust stroke? Not to mention torsional vibrations on the camshaft. What do you think?
I think there was an VW engine that adjusted valve lift on one of the intake valves only, but I can't quite remember if both valves still closed at the same time despite that.
The valves would still close well before TDC on the compression stroke. The camshafts don't touch the valves directly, as long as there's some clearance between the rocker and valve stem any harmonics would/should be taken up by a lost motion assembly. Still I imagine you're right, that doesn't mean that they can't do both, different sized valves different lift profiles. The difference doesn't even have to be large, a few tenths of a mm difference can have big changes.
