Denver Automotive Machine Shop/Service And Parts

The Antidote to Wear
One of the key components in any racing oil is anti-wear additive.  Typically this includes ZDDP (zinc dialkyl dithiophosphate) as well as other ingredients such as moly. ZDDP is a mixture of zinc and phosphorus, although many people simply refer to it as “zinc”. The exact proportions of zinc and phosphorus in ZDDP can vary somewhat but generally there is slightly more phosphorus than zinc. Under extreme pressure, these compounds provide a protective barrier that prevents metal-to-metal contact and wear.
Everyday motor oils for passenger car and light truck applications that meet current API (American Petroleum Institute) “SN” specifications and/or ILSAC GF-5 specifications contain reduced levels of ZDDP (less than 800 PPM). Phosphorus is great stuff for preventing wear, but it can also contaminate catalytic converters and oxygen sensors, reducing service life ­– especially if the engine is burning oil due to worn valve guide seals or piston rings. The amount of ZDDP in current motor oils was reduced from earlier levels of 1200 PPM because most late model engines have roller cams or overhead cams. Reduced friction in the valvetrain means these engines don’t need as much ZDDP for wear protection. But that’s NOT the case with performance engines or older engines with flat tappet cams. They need higher levels of anti-wear protection.
Most people assume that one of the hallmarks of a racing oil is that it contains at least 1500 PPM of ZDDP, or even more (some contain as much as 2000 PPM of ZDDP). That’s generally true, but there are performance lubricants on the market that contain as little as 1100 PPM of ZDDP thanks to the higher quality base oils in the product and other additives (such as moly).
The exact amount of ZDDP in a racing oil doesn’t matter, nor does more always mean better as long as there is enough to protect the valvetrain components against wear. Some engines need more, some can get by with less. Extremely high RPMs and extremely stiff valve springs can place tremendous loads on the cam and lifters, so foe these applications a racing oil that contains extra ZDDP or other anti-wear additives is usually a must to prevent cam or valvetrain failure.