My new adjustable push rods all have a burr at the center of the face. It looks to me that this burr will score the cam lobe. I faced an old push rod on my valve machine and it looks real good. So with these T motors, is this the way to go? Advice? PK
Just careless Chinese machine work, huh Pat? Seems like a guy could just "touch up" with a few strokes of a fine file and finish polish with emory paper,.....???
In a perfect world the tappet should have a convex radius on the foot. Ford factory tappets are nearly flat. The radius helps promote rotation.
If my memory serves me right, Mopar tappets have a 35 inch radius on the face. That and a slight taper to the lobe ensured the tappets would rotate.
Send them back or take them to a shop that has a tappet grinder and have them refaced. You can't grind them on a valve grinder. As correctly stated above the tappet face should be concave. A cam lobe the size of a T should have a radius around 100". I'm referring to the cam end of the tappet- not the valve end. If you're grinding the valve end then the valve grinder is the way to go.
Dan, I hope you meant CONVEX.
Con something, hows that? Yes thanks for catching the misspelling. Dan
Well, yes. There lies all of the meaning.
Concave: curved inwards.
Convex: curved outwards.
SO, which do we want: an outie or an innie?
Outie- sorry if I confused anyone! Cam lobes are ground with a very slight taper from one end to the other- only a few thou, but it is enough to impart a slight rotation to a crowned follower.
Yes Dan, that places the contact point slightly off center to the tappet and thus causes rotation.
2013 discussion on the same subject: