What is ZDDP?
ZDDP, zinc dialkyl dithiophosphate, is a compound developed in the 1940s. Petroleum companies added it to their motor oils to enhance lubrication. It was held in high regard as being the most cost effective metal on metal anti-wear additive available. The silicate-based fluid got its start in airplane engines. Designers discovered it also worked well in car and truck engines.
Studies found the anti-wear protection with flat tappets and overhead cam lobes impressive. Further investigation uncovered that the benefits applied to any engine part under considerable pressure. In fact, the ZDDP oil additive substantially reduced noticeable wear in any metal to metal situation.
All tests we’ve reviewed conclude that ZDDP is effective at increasing the longevity of internal engine parts. When properly formulated with base oils, ZDDP is also known to have antioxidant and corrosion resistant properties. These are useful qualities for classic car enthusiasts since their engines can sit for extended periods.
How ZDDP Works
As temperatures rise and surfaces come closer together, ZDDP decomposes, and the resulting chemistry protects critical metal surfaces. When parts move during operation, any sliding or rolling motion takes place on top of or within the ZDDP anti-wear film, which reduces metal-to-metal contact. This is especially important in modified engines with flat-tappet camshafts because the engine is creating more horsepower than it was designed for, which puts more stress on the engine. High-tension valve springs, often used in racing applications, also increase the potential for cam wear and require additional ZDDP.