Unless you’re directly involved with engine design, it’s hard to keep up with all of the creative methods engineers have used to integrate variable valve actuation into a standard internal combustion engine. In this day of computer controls, you would think mechanical methods would be losing ground, but I received a note from Danny Williams about the Williams Helical Camshaft and it’s pretty neat.
The helical camshaft has a cam lobe design that changes duration as the cam is twisted. It goes from relatively short duration to almost as long as you like. They made a replacement for a 250cc Suzuki camshaft to demonstrate how it works and it seems to do the job.
The precision of computer control and electronic actuation of each valve without even using a cam strikes me as the high tech future instead of using mechanical means where a cam is involved, but a mechanical method might work better in smaller or less expensive engines or it might be better in all sorts of engines. Like I said, unless you do this sort of thing every day, sorting through the pros and cons of each system is difficult.
There is a lot of material on the Williams website going into great detail plus a number of videos. For those who prefer to see a solution machined in metal instead of designed on a computer, the helical cam is worth a look. Check it out.