...ith non-roller rockers, that perpendicular is measured from the rocker arm foot to valve tip contact, through the centerline of the rocker shaft, but with roller rockers, it's taken from the center of the roller rocker tip, through the center of the rocker shaft. Is this correct?...
Having gone from Crane ductile iron to Harland Sharp rollers, this is how I understand how things work.
The pushrods that were in the motor looked like $#!t, and two were bent, so I cut a couple up and made adjustable ones for checking geometry. They were too long with the Comp rollers. The adjuster was all the way out, and the lifter plunger was compressed at least .100". They look like they measure 8.547", or .030" under stock. With the stock rockers back on, it looks like the shaft needs to be lowered if we're going for perpendicular at half lift, but it still gets max lift, so I'm thinking just use the stock rockers since lift is only .496". With non-adjustable rockers, how much preload should I shoot for since I need to order new pushrods now anyways?
The third element here is where the rocker arm adjuster and pushrod are located. If all three pivot points are on a line, then there should be minimal issues/minimal excess wear and maximum lift. I've measured where too short pushrods have reduced lift because the adjuster ball is too low, and this results in excess horizontal movement in the pushrods on the rocker end. With shaft mounted rockers, pushrod length is the last thing I consider
