AMSOIL has released a new motor oil series that is laden with zinc and phosphorus for older cars and street rods. The new “Z-Rod” Synthetic Motor Oil Series is available in 10W-30 and 20W-50. This formulation will be especially attractive for applications with flat tappet cam engines.
So why create a special motor oil for older cars and those equipped with flat tappet camshafts? Newer generations of engine oils are mandated to have strict limits on the content of additives such as zinc and phosphorus. These additives can cause problems with the emissions equipment on today’s vehicles. As auto manufacturers have replaced flat tappet cams with hydraulic roller cams over two decades ago, lower levels of these additives is not an issue. Flat tappet cams are under much more pressure than modern hydraulic roller cams. If a newer specification of oil with less zinc/phosphorus is used, accelerated wear is the result. Here a great article illustrating the Difference Between Flat Tappet Cams and Hydraulic Roller Cams.
Another issue unique to collector cars and street rods is that they tend to spend a lot more time sitting around and looking pretty than they do on the road. AMSOIL recognized that this type of engine will be far more prone to internal rust and corrosion than your daily driver. Therefore AMSOIL incorporated an especially robust additive package of rust/corrosion inhibitors.
Z-Rod 10W-30 and 20W-50 is now available in US quart bottles.