Posted by Leland on December 04, 1998 at 12:38:27:
In Reply to: Re: rotary valves posted by BobF on December 04, 1998 at 07:56:06:
Yep, that's right --
The only actual bearing surfaces are the spindle on the "top" and the bearing on the bottom. It's not like a piston valve where the whole piston _is_ a bearing surface; the rotor and its wall should not be coming into contact with each other. The small enclosed bearing surfaces, combined with the fact that that they just go round-and-round instead of back-n'-forth, lets lubrication stay where it's needed on rotors for longer periods of time than pistons -- which means that you can "get away with" fairly infrequent additions of rotor oil.
Adding oil down the tubes or leadpipe can help in preventing corrosion, but at the same time, it can allow dirt and/or grease to migrate to the rotor from the rest of the horn, which might slow things down.
So, yeah, there's less daily maintenance necessary for rotors than pistons, and the tradeoff is that taking rotors apart involves more effort.