Just discovered this forum. I have been searching for a forum on camshaft design. That is, actual design like ramps, profiles, materials, machining, and so on, as opposed to "what cam should I use?" I found a gear forum but no cam forum. Anyone know of one, or is this forum the appropriate place?

I have many old SAE papers and the polydyne papers from Machine Design. I worked with Harvey Crane for a while on a new aircraft cam, and also know the guys at Comp Cams as they are across the street from where I used to work. I eventually wrote my own program but I still do not know as much as I want to.

There is a formula in Joseph Harralson's "Design of Racing and High Perforance Engines" that might be of some help to you. If you're not familiar with the book (ISBN 1-56091-601-X) it is basically a collection of SAE papers. Here's the excerpt which deals with abnormal valve motion:

"VALVE MOTION- Abnormal inlet and exhaust valve(Reducing Valves) motion is a major obstacle in the development of high-speed engines. The main factors influencing valve motion are:

1. The degree of ridgidity in the valve train.
2. The equivalent inertia weight of the moving parts in the valve train.

For the tappet-type and rockerarm-type of overhead cam valve mechanisms, we determined the engines speeds at the initiation of abnormal valve motion (such as jumping or bouncing) and plotted these data as a function of the equivalent inertia weight of the valve train.

It can be seen that the abnormal motion begins at a higher engine speed for the tappet-type, which can be attributed to the higher ridgity of this system. The equation generally used in valve mechanism design is expressed as:

Ne = 2C SQRT[(Fs