A classic car engine needs a zinc additive or a zinc replacement in the motor oil to prevent metal parts from touching and wearing down too soon. That’s because flat tappet camshafts create a lot of pressure in the valve train when they are operating, and non-zinc modern engine oils won’t provide the needed amount of lubrication to keep those flat-tappet lifters from wearing down too quickly.

The zinc that is used in these additives – most commonly zinc dialkyl dithiophosphates, or ZDDP – bonds to the metallic surfaces of the engine’s mating parts and forms an anti-wear coating. As the temperature rises and those metal parts come into contact, ZDDP decomposes and helps create a lubricant film that minimizes wear.

Zinc is still a popular choice for engine oil additives because it has been well tested over the years, but newer technologies are coming to market that could eventually make zinc unnecessary. Those technologies include molybdenum and boron additives, which have the potential to provide similar anti-wear protection as ZDDP while also helping the engine run more efficiently.

Until those advanced alternatives are ready to hit the market, a ZDDP additive is the best way to ensure that your flat tappet camshaft gets the lubrication it needs to stay in good condition and keep your engine running as smoothly as possible. To get the most out of this engine oil supplement, consider pairing it with a premium engine oil designed to work with it, such as the Lucas Oil 10063.