For close on 40 years i have used Castrol GTX 20w-50 in all of my older and modified vehicles. i have been concerned about the changes in contemporary motor oils of all brands that effect older engines with flat-tappet camshafts, and i have inquired of Castrol to determine what products they may offer to meet my needs. In responding today, a company representative referred me to this URL.
http://www.castrol.com/castrol/genericarticle.do?categoryId=82915470&contentId=7032644 In the message that i received today, Castrol indicated that "the new formula Syntec 20W-50 for classic cars is actually API SM. The statement 'Recommended for Classic Cars' should be visible in the middle of the back."
According to Castrol, "the Zinc levels (actually the Sulfur and Phosphorus levels) in the API SM / ILSAC GF-4 viscosity grades are defined by a table of requirements but in basic terms 20W-50 is not held to the same requirements as the lower viscosity grades (5W-20, 0W-30, 5W-30, 10W-30); 20W-50 can be higher."
Castrol claims that "current Syntec 20W-50 (for classic cars) is actually a modern premium quality API SM product that has been Zinc boosted to Zinc levels that are reminiscent of Zinc levels from historic API categories such as SG when flat tappet cams with high spring loads were common in the fleet. For reference, note that the API SM category has the most rigorous passenger car engine oil (PCO) test performance requirements in the history of the API PCO categories."
"The level of Zinc in the new Syntec 20W-50 is a minimum of 1200 ppm, which will provide excellent anti-wear protection for the cam and lifters in a flat-tappet cam engine."
In its statement, Castrol estimates that "Castrol SYNTEC 20W50 Classic Car formula should be widely available at retail locations by October 2007. We cannot disclose exactly where the product is currently available, although it has been ordered by several key customers. Unfortunately, we can only control when we ship the product, not when our customers' inventory allows it to make its way to the shelf."
This is the response of one manufacturer of motor oil for the performance market to the questions currently under discussion. We shall see whether it works as claimed . . . and how much it costs.
God's Peace to you.
d
Inliner #1450
