In the old days, people living in cold climates put in a thinner oil for the winter with a “W” or cold temperature-viscosity rating. Although they poured better at low temperatures, straight-viscosity “W” oils, in turn, didn’t do a good job of protecting engines once they reached normal operating temperatures, so they weren’t recommended for sustained high-speed driving. The oil industry developed “all-season” multiviscosity oils to solve the problem, but some of the early products didn’t hold up under heavy-duty operating conditions, tainting the reputation of multiviscosity lubricants.
Yet today’s modern oils are vastly improved over those of 20 years ago. For oils that meet the current “SJ” service designation, viscosity breakdown is no longer a significant problem, thanks to modern formulation technologies and viscosity enhancers. Auto manufacturers have also redesigned their engines for tighter clearances and instituted precision machining techniques that take advantage of thinner oil to deliver improved fuel economy through reduced friction.
Like the OEMs, the racing sector has discovered that friction reductions plus precision tight clearances yield greater efficiency and more power. Racers also know that most engine wear occurs at start-up, so it’s critical that engine parts receive proper lubrication as soon as possible–hence the need for an initially thinner, so-called “winter” oils. Today, few racers run a single-viscosity motor oil.
Synthetic oils, pioneered in the ’70s by Mobil and Red Line and now available from most major oil companies, taking the all-season, multiviscosity approach as far as possible. Unlike traditional mineral oils that are produced by distillation and further refining of existing crude oil stock, synthetic lubricants are made through chemical reactions. These new oils aren’t synthetic or artificial in the sense that they’re manufactured out of whole cloth–they still have the same natural ingredients found in “real” oil. But in a synthetic lubricant, these ingredients are recombined like chemically to yield synthesized-hydrocarbon molecular chains with unique characteristics and uniformity not found in even the highest-quality traditional motor oils. Typically, the best synthetic oils use a combination of up to three different synthetic base fluids–polyalphaolefin (PAO), synthetic esters, and alkylated aromatics. Most new engines come from the factory with synthetic oils. If you ask me, I change even my used engines to synthetic oils, simply because it rules.
Because a synthetic oil’s molecules are much more consistent in size and shape, they are better able to withstand extreme engine temperatures. Mobil 1 synthetic is said to be capable of protecting engines “at well over 400 degrees F”; in the real world, most racers have no problem running synthetics up to 290 degrees F under prolonged use, but they get really concerned when a conventional exceeds 260 degrees F. Interestingly enough, conventional oils can breakdown and catch fire at temps. over 260 degrees F., where the synthetics, as stated earlier can go well over 400 degrees without breakdown or catching fire.
Because a synthetic oil is chemically produced, there are no contaminants in the oil. By contrast, conventional oils contain small amounts of sulfur, wax, and asphaltic material that can promote detonation as well as varnish and sludge buildup. With no wax, synthetics will flow at much lower temperatures than conventional oils. In fact, synthetic oils are now available with viscosity ratings as low as 0W-30, as in Mobil 1′s new Tri-Synthetic blend or Castrol Formula SLX. These oils flow more than seven times faster than a conventional 5W-30 motor oil during initial start-up, yet at normal operating temperatures act like a regular Grade 30 oil.
An 0W-30 synthetic oil is capable of pumping easily at -62 degrees F and flowing at even lower temperatures. Conventional oils are essentially frozen solid at that temperature, so there’s simply no conventional equivalent to this new grade. There are 5W-30 conventional and synthetic oils, but even here, the synthetic has a proven advantage: Mobil 1′s 5W-30 will pump at -58-degrees F, compared to about -35-degrees F for a conventional oil.
However, thinner oil also translates to lower oil pressure: The 0W-30 oil developed 10 psi less than the baseline 20W-50. Only 46 psi was on tap at 6,200 rpm–kind of shaky as most gearheads like to see at least 10 psi per 1,000 rpm.
This is not necessarily true, excessive oil pressure is not necessary for good lubrication, in fact to much oil pressure can cause failures due to the fact that the oils runs so quickly through the engine that it fails to lubricate properly. The engines ran fine with a little less oil pressure, and the bearings looked great on teardown, verifying synthetic manufacturers’ claims that their products’ greater shear strength more than makes up for lower viscosity. Is 10 hp and 15 lb-ft worth paying two to four times more for a quart of oil? Or the potential for extended engine life? You bet it is, not only does your engine lubricate much better, but you can extend oil changes from 3000 – 4000 miles to 6000 – 8000 miles, safely. The moral here is that you will save money in the big picture of things. there will be less problems with your motor and it will last many more miles.
GotEngines.com encourages the usage of superior lubricants. A lot of engines are purchased because of oil failure, so this is not a good place to cut corners, as it is not a good idea to ignore your cooling system. The GotEngines.com/blog is full of critical engine saving tips. Read and Enjoy.
