In an answer to another questions @Ceshion introduced a fascinating kind of valve train that I have never heard of, desmodromic valves, as introduced by Ducatti.
That answer is here:
What are the various kinds of tappets / lifters and the advantages / disadvantages of each
and here is the image she provided as an example:
Here are the specific questions:
- Are these only used in motorcycles, if not, where else is this used?
- Given the complete lack of valve float, just how high can these rev? What is the next limiting factor in how high they can rev (ignoring the rest of the engine for now. Unless the only other thing that would rev limit is something in the bottom end.)
- How much more or less reliable are these than the usual modern valve train setups?
- Are these restricted to racing or are there street applications for these?
- Does anyone but Ducatti use these or are they patented by Ducatti?
- Given the lack of valve float, how much bigger and heavier can the valves get to allow more flow and more power?
- From the looks of it, the position of the valve is totally dependent on the cam followers for both opening and closing cam shafts putting it exactly where it needs to be. There are no springs or hydraulics to take out any slop in the system. How does a system like this account for wear on the mating surfaces? Is there any adjustment in a system like this? Do they leak more than the usual setup because it's hard to get the closing and opening cams to position the valve for a good seal?
- Does a system like this require higher oil pressure to prevent premature wear as the revs go higher?
The high revs means so much more power, there have to be down sides to this for them not to be in use in a lot of places.
Thanks in advance!