Valvetrain Geometry: Mid-Lift Method vs Valve Tip Pattern

[MadBill]

Regardless of whether or not the stylus is centered on the mid height of the roller, due to the latter being a perfect cylinder* the contact point of the indicator will remain a fixed distance outboard of the actual center of rotation as the tip rolls on the stem. *After a recent experience with eccentric rollers I no longer make this assumption..

[Wolfplace]

I thought I would post this tool again. It has been posted before. This will show exactly how much sweep you are getting. I made one up like it.

Don't tools like this depend on the end of the rocker arm having a radius equal to the distance from the rocker pivot, and centered on the pivot? Is that generally true of rockers? The one in this picture looks like it has a much smaller radius than that, which I think would cause a larger indicated reading than the "true" motion of the roller on the valve end. Curious minds want to know

I phrased this poorly, instead of rocker pivot I should have said the center of the roller tip shaft. In the picture by eye it looks like the radius on the end of the rocker is not centered on the roller tip, so the dial indicator won't accurately show the lateral motion of the roller tip.

If it stays in the same relative position on the roller yes it will, makes no difference if it is perfectly centered or not it is measuring the lateral movement of the roller across the tip referenced from a single point but notice I changed the tip to a wide flat one to be sure it isn't affected

[ijames]

My bad, in Mike's picture it was obvious that the indicator was riding on the roller, but in the first picture from 89ta there was only the side view and I aSSumed that the end of the rocker was closed and the indicator was riding on the end of the body, and not the roller.

[andyf]

I thought I would post this tool again. It has been posted before. This will show exactly how much sweep you are getting. I made one up like it.

That is a tool I designed a few years ago. I used to sell those tools but they were a pain to make and most people didn't want to pay me for my time so I stopped making them.

[randy331]

If you set up a Jesel shaft rocker using the tool they send with the rockers, it won't be mid lift geometry.

Is Miller right, or Jesel ?

Randy

[Hectori]

If you have wide contact pattern, would it be preferred to be centered on the valve, or offset to one side, when you consider quide wear. I would think that centered pattern would promote rocking of the valve, as rockers thrust goes side to side from valve centerline. Compared to offsetting the patter so that it stays in one side all the time, where force that pushes valve offset is little greater, but there would be less rocking. Just thinking.