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Early last decade, in a moment of revelation, engines used on the NASCAR Cup circuit progressed from 5160 alloy steel cams with stellite-coated lobes to tool steel cams that operate in conjunction with DLC-coated tool steel flat tappets. The combination excelled immediately, and it was inevitable uncoated variants of these tough, hard-wearing tappets would emerge for use on cast-iron camshafts.
“For years,” said Bob Fox, head of Trend Performance, “we had supplied one-piece pushrods and, some time later, tool steel piston pins to the NASCAR teams. Then about four or five years ago, about the same time as the oil companies changed the constituents of their lubricants, we were invited to enter the tool steel solid flat tappet market. Because the materials and processes used in the production of solid flat tappets are so similar to those used in the manufacture of the piston pins, the decision was easy. For our first year or so, we requested an open exchange of information from a couple of Cup teams, which proved to be a big advantage.”
Derived directly from Cup racing, these new uncoated versions benefit from their NASCAR heritage. Obviously they are hard (63-64RC) and tough, but are also light (68+grams) with an unsurpassed super fine surface finish (1-2Ra) on the contact base. But it is the economies of scale that have made them accessible to all types of racing.
“Trend is already engaged in large volume production of tool steel solid flat tappets for NASCAR teams,” said Fox, “and we have all the processes in place to make this happen for the weekend racer too.”
One real benefit to the new tappets is their ability to be reused over and over again. In most cases during break-in, a set of cast tappets will mate to a cast cam. Those tappets must remain mated to a particular cam lobe. These new tool steel tappets can be mated to any number of different cast cams as well as returned to the factory to be re-ground. All of which makes them more of an investment that can last indefinitely.
Cumming, Georgia engine builder Johnny Thomas often poses the question, “Have you ever noticed how some racers never have the money to do it right, but can always find the money to do it twice?”