Jerry, funny that you should mention that, I used one of those when I helped out in the machine shop at the auto parts back in the early 60’s. When I did my valve job a couple of years ago, lacking that Sioux equipment, I made up a small base plate with a perpendicular boss that fits the bore of the rocker. I have one side of a bench grinder equipped with a 3M Scotch-Brite rubber bonded finishing wheel. I simply square up the tool rest on my grinder, place the rocker arm over the boss on my fixture and slid it across the wheel in an arc to radius the contact surface square to the bore. I’ve got the fixture around here somewhere but can’t find it right now. Here is what the rockers looked like before and after.
http://www.pbase.com/dennygraham/image/121940017 As far as re-boring a rocker arm, I would think that would be a rather difficult task. The bore is the datum for both the other features to reference to. During manufacture I’m sure the bore was machined first or used as Datum ‘A’ for you GD&T types. Then the thread for the adjuster and contact surface was machined in reference to that. To reverse the machining process you would have to find a surface that would locate the bore inline with the machine axis before you could re-bore it. The only feature that you could use to reverse machine them with would be the adjustment thread. In other words, I doubt very seriously that rockers that didn’t have bushings originally were ever re-bored to take bushings.
Denny Graham
Sandwich, IL
