Synthetic Motor Oil: The Auto Industry’s Best-Kept Secret

Base article is from Muscle Mustangs and Fast Fords Magazine, with additional commentary by Performance Oil Technology, L.L.C.

Have you ever heard the story about the light bulb that doesn’t burn out or the razor that never dulls? Sure, these stories get exaggerated, but sometimes there’s an element of truth to the rumors leaking out of a manufacturers skunkworks. One particular rumor that sounds too good to be true is “an experimental motor oil that increases horsepower, practically stops internal engine wear in its tracks and improves fuel efficiency.”

Well, synthetic motor oil is not a rumor. It’s been in use ever since World War II (the Germans used it on the cold eastern front because conventional oil wouldn’t flow in the arctic-like weather). Even though it sounds too good to be true, synthetics do reduce engine wear, improve gas mileage and increase horsepower. This is because synthetic oil molecules are superior in a number of ways to mineral-based oils

Synthetic Oil is Superior to Mineral-Based Oil in Every Way:

Without getting too technical, suffice it to say that synthetics have a much higher resistance to heat than mineral-based oils. Because synthetic oil is composed of molecules that are uniform in weight and shape, its heat of vaporization is much higher (more than 600 deg. F.) compared to conventional oil, which begins evaporating at temps as low as 350 deg. F. This added stability at high temperature means that your hard-working engine wont burn up as much oil- and that means less sludge and fewer varnish deposits in the engine.

Added lubricity is another attribute of synthetics. The uniform diameter of synthetic oil polymers allows them to more easily slide over one another. The resultant reduction in friction shows up as more horsepower and torque and reduced internal engine wear.

Higher film strength, however is one of the major benefits of synthetics. Film strength is what keeps oil molecules from being pushed away from each other under pressure. Mineral based oil has a film strength of about 400 psi, while synthetics usually exceed 3000 psi. In an area where two metal surfaces meet, the film of oil between them prevents them from rubbing and wearing away at each other. Synthetics do a better job of this than conventional mineral oils. It takes more than seven times as much pressure to squeeze synthetic oil from between two surfaces than mineral-based oil. Consequently, synthetics are much better at keeping your engine like new.

Not All Synthetics Are Created Equal:

Please be aware that not all synthetics are created equal. There is wide differences in quality and protection provided by the various synthetics. Additionally, not all synthetics are 100% synthetic. Many are partial synthetics marketed under the perception of full synthetics to the unsuspecting consumer or even hydrocracked oils such as Castrol Syntec, for example, which is a hydroisomerized petroleum oil marketed under the disguise of a synthetic (there is a full article on this in our Informative Articles section detailing the recent battle between Castrol and Mobil). There are no PAO (polyalphaolefin) synthetic molecules in Castrol Syntec, yet because of legal fanageling with the definition of synthesized motor oils they can legally be called synthetic. Basically, they changed the definition of a synthetic to fit their process of highly refining a petroleum base oil, called hydrocracking and fought with Mobil and the National Advertising Council to loosen the definition of a synthetic.

Film strength is important in another way- cold start protection. Regular mineral-based oil will not remain as a boundary layer (a uniform thin coating) on metal surfaces when an engine is turned off. Mineral-based oil drains off parts and out of passageways into the oil pan. Additionally, mineral-based oils contain waxes and paraffins that come out of the earth and solidify when it gets colder outside, therefore making it even harder to pump the oil when cold. When you crank your vehicle the metal surfaces (crankshaft, camshaft, lifters, connecting rod bearings, piston pin bushings & bearings, piston, rings and cylinder walls) that require lubrication are not fully lubricated in the time it takes for the oil pump to pressurize the lubrication system and supply oil to the engine.