More oil info!

Last week I had e-mailed Royal Purple's technical dept, regarding the suitability of their oil (IIRC is a full synthetic) for use with flat tappet cams. I thought it would be intertesting to post the response I received. I have edited the post somewhat to protect my, and the responders privacy.

-----Original Message-----
From: Joe Esterl
Sent: Thursday, June 21, 2007 11:06 AM
To: [email protected]
Cc: [email protected]
Subject: Automotive Questions

Technicians,

Is Royal Purple oil compatible with flat tappet cam style V-8s? I see no mention of ZDDP in your oils and have read of many flat tappet cam failures due to the lack of this additive in conventional mineral based oils. I will be firing up a new engine in a couple of months, and plan to break it in with Valvoline racing oil, but would like to switch to your oil after 2000 miles.

Thanks,

Joe Esterl
Systems Engineer

Joe,

Only the newer API SM service classification oils have significantly reduced the levels of anti-wear additives and then only those in the multi-weight SAE 30's and SAE 20's. These oils (SM) are required to use about 20-35% less than the API SL to meet EPA emissions requirements.

Royal Purple has continued to make only the API SL and the heavy duty diesel API CI-4 as we are not currently convinced that the API SM is an advancement in engine wear protection.

We would recommend using any of the RP oils in your engine but for your configuration – the RP5w30, RP 10w30, RP 10W40, RP 15W40 or RP 20W50 in the street oils as well as the MaxCycle 10W30, MaxCycle 10W40, MaxCycle 20W50 or the XPR 5W30, XPR 10W40 or XPR 20W50 are all good choices for your flat tappet cams.

The 2,000 miles on the Valvoline is a good a break in on the motor.

Have a great day.

Kyle Neal
Technical Sales Representative
1 Royal Purple Lane
Porter, TX 77365