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Originally Posted by Moppie
Actualy many Japanese Over Head Cam engines use some form of lifter/tappet between the cam and the valve, often with a rocker or similar inbetween (only its called something else, and Ill be damned if I can remember what, SAABJohn knows!).
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I think the word you're looking for is "follower."
I also do mostly work with American engines, so I'll give you my perspective on it until SAABJ shows up and gives us the right answer
For the most part, no. Cams (unless they are a roller lifter design) are hardened so the metal-to-metal contact doesn't chew the lobes. This hardening is only on the very thin surface layer or the cam. You can run on that thin layer of hardened metal for hundreds of thousands of miles, but you break through it and you're lucky to make it 100 miles. I use the analogy of an M&M. You can suck on the hard candy shell for hours, but once it breaks through, the whole chocolate center collapses in short order.
Lifters, followers, etc, establish a wear pattern on both their surface and the cam lobe. Introducing new lifters to a worn cam will cause it to establish a new wear pattern, most likely breaking through the hardened shell. You can imagine the mayhem that happens. In best case scenarios, you replace two lifters and you go on your merry way, or sometimes with light spring pressures, the cam lobe wear is slow and you can get a few metal shavings over the next few years and slow lobe wear. Worst case scenario like I found was catastrophic failure after a mere 230 miles.