Flat tappet cams can be damaged by using modern engine oils that lack zinc and associated anti-scuff additives. Zinc can damage catalytic converters, so it's slowly been eliminated in modern engine ...

For the last several years, many engine builders and individual hotrodders have experienced a raft of seemingly unexplained flat-tappetcamshaft lobe failures. As one engine builder puts it, "I've ...

It's been all the talk on internet forums, club meeting hangouts, and in enthusiast garages across the nation—the loss of zinc and other protective "barrier" chemicals in modern oil damaging ...