Do your motor oils contain zinc/phosphorus?

Does Royal Purple maintain its purple color after it’s put into service?
August 17, 2018
Can your oil be used with flat tappet cams?
August 17, 2018
Yes. All Royal Purple® engine oils contain the zinc/phosphorus compound zinc dialkyl dithiophosphate (ZDDP), but the maximum amounts are restricted by the current API oil specifications. For stock, non-performance automotive street applications, API SN licensed oils are OK. For better wear protection, Royal Purple HPS and XPR lines of engine oils are formulated with a higher concentration of the zinc and phosphorus anti-wear additive and are suitable for ALL flat tappet and roller tappet camshaft valve trains. For a specific recommendation, contact our tech department at 888-382-6300.
Category: Motor Oil