Re-using Used Lifters on Another Cam
Cams lobes are not ground flat...they have a slight taper to allow the lifter to rotate.
Plus the lifter bores are offset from the lobe to help.
Inside Trend's High-Tech Flat Tappet Lifters
Interesting video about those high end lifters made from tool steel. Likely super expensive.
Never realized the cam lobe was tapered. Or that the lifter end was spherical ground. Then again, I've never seen a lifter surface with grinding marks as rough as the lifters shown in the second grinder video. Most lifters I've seen have a high [almost mirror] surface finish. The grinding machine looks like something out of the 1950's. I wonder if Model A Fords had them?
So I decided to do some checking on an old 340 camshaft. It had CWC cast on one end, blue and red paint near the ends, and numbers 1196 stamped on the end. ~.505 lift. Aftermarket cam with new lifters. Checked the lifter ends: 4 were convex, 5 were concave, the rest were flat. About .002 high crown. All had a high surface finish. All the lifters were rotating.
Then checked the cam, looked like it had low miles. The tops of the lobes were shiny, the base circle area had most of its black color from heat treating. The base of the lobe measured .002 different from one side of the lobe to the other. The height of the lobe also measured .002 different. The angle of the taper direction changed from lifter to lifter. Probably 50/50. [guess]. It was a casting. File tested for hardness. The as cast core seemed soft. The lobes were harder. But not as hard as expected. Maybe Rc 45-50.[guess]
