Oil Technology Today vs Yesterday
Today’s oils are not the same as they were even a few years ago.
Phosphorus and Zinc Reduction
- Phosphorus degrades catalytic converters
- Zinc & Phosphorus content unlimited before 1993
- Phosphorus now limited to max 800 ppm (API SM / ILSAC GF-4)
- Mandated for 10W-30 and lower – still occurring in higher grades
- Diesel oils now limited to 1,200 ppm Phosphorus (Oct. 2006)
- Exhaust Gas Recirculation Valves
- Increased drain intervals – less waste oil
- Restricted Sulfur content
Today’s Street Oils Are Not the Same as They Used To Be
As Comp Cams recently pointed out in a Tech Bulletin, “Today’s engine oil is just not the same as it used to be, thanks to the ever tightening environmental regulations.”1 The EPA, car manufacturers, and the American Petroleum Institute (API) have done a great job reducing emissions and extending the life of emissions control equipment. However, the reduction in emissions has coincided with a reduction in traditional, performance proven anti-wear additives (i.e. zinc dithiophosphates). In the years ahead, the levels of formulated anti-wear will be further reduced. While this is great for the environment, it is bad news for your racing engine.
As stated in the book “Lubrication Fundamentals”,”In heavily loaded applications (i.e. racing engines), flat tappet cam followers operate on partial oil films at least part of the time. Lubricants with anti-wear additives are necessary if rapid wear and surface distress are to be avoided. The oil additive Zinc Dithiophosphate is to provide anti-wear activity for the camshaft and lifters. With the increased use of roller follower cams (in production cars), the requirements for anti-wear have been changed to prolong the life of emission control devices.”2 The increased RPM and related increase in valve spring pressure in today’s racing engines require higher levels of formulated anti-wear, especially in flat tappet engines. Again, the book “Lubrication Fundamentals” sums this up, “Loading on the rubbing surfaces in the valve train may be high, particularly in high speed engines, where stiff valve springs must be used to ensure that the valves close rapidly and positively. This loading can result in lubrication failure unless special care is taken in the formulation of the lubricant.”3
This is where Joe Gibbs Racing found ourselves in the late 1990’s. The valve train loads in our flat tappet NASCAR Sprint Cup engines exceed 500 psi in order to turn over 9,000 rpm. The high loads and long duration races (up to 600 miles) required more formulated anti-wear chemistry than even the best API rated synthetic passenger car oils offered. Joe Gibbs Driven Racing Oil was born out of the need for a high quality, synthetic oil that could protect both our flat tappet Sprint Cup and roller follower Nationwide Series engines without giving up horsepower. Over the last seven racing seasons, we’ve developed a family of lubricants that provide the necessary levels of advanced formulated anti-wear chemistry to protect highly loaded racing engines from break-in to endurance race conditions.
We’ve also learned a few things about oil that can help you make better educated decisions about which oil to use in a particular engine.
Additives Make a Difference – As referenced earlier, having the correct additives in the correct amount formulated into the oil separates racing engine oils from passenger car engine oils. You wouldn’t use a stock piston in a built race engine, and the same goes for oil.
Surface Finish Matters – “The minimum safe film thickness is a function of the roughness of the surfaces. Rougher surfaces require thicker films (higher viscosity oil) to prevent contact of surface asperities through the film. On the other hand, the finer the surface finish, the lower minimum safe film thickness (lower viscosity oil) and the less clearance is necessary. Since film thickness decreases with increases in unit loading, if the minimum safe film thickness is lower as a result of finer surface finishes, the allowable unit loading is higher.”4 The improvement of surface finishes through chemical polishing and tape polishing has enabled JGR to lower the viscosity of oil we use without sacrificing wear. Especially at break-in, the better surface finish you begin with, the fewer problems will be encountered during break-in. The polished foot flat-tappet lifters currently available provide superior surface finish compared to non-polished lifters.
Choose the Correct Operating Viscosity – Viscosity is a measure of an oil’s resistance to flow, and viscosity decreases (flow increases) as temperature increases. With that in mind, the operating temperature of the oil plays a major role in the selection of the proper viscosity oil. Too high a viscosity oil can result in excessive heating and lower mechanical efficiencies. Too low a viscosity oil can lead to excessive metal to metal contact of moving parts. When oil is of the correct viscosity and has adequate anti-wear characteristics, wear due to metal-to-metal contact is kept at a minimum. As previously stated, improved surface finishes allow the safe use of lower viscosity oil for better cooling and improved efficiency (horsepower). In addition to operating temperature, engine speed (RPM) and load also effect the operating viscosity and film thickness of an oil. Higher engine loads (cylinder pressure) decrease film thickness, but higher engine speeds (RPM) increase film thickness. Learn more about choosing the right viscosity.
What can you do? – Check your oil bottles for the API donut. If the oil you currently use carries an API donut, it probably lacks the amount and type of formulated anti-wear chemistry found in a true racing oil. Choose an engineered fluid like Joe Gibbs Driven Racing Oil that’s designed to meet the higher anti-wear needs of your racing engine. For more technical advice and product descriptions, call our tech line at 866-611-1820.
All material referenced from Lubrication Fundamentals, Second Edition, By D.M. Pirro and A.A. Wessol, Published By Marcel Dekker, Inc., Copyright 2001 Exxon Mobil Corporation