The Thick and Thin of Wear Control
In Some cases, for wear control, any fluid will work; top-of-the-line AMSOIL lubes to bottom-shelf petroleum lubes. So why use the best when the rest will do? Because nothing's ever as simple as it seems.
FRICTION AND WEAR
Encountered in all machine elements, friction is the resistance to sliding of two contacting surfaces. Friction results as contact areas - microscopic surface high points - shear.
Wear results as surfaces lose enough material to shearing to impair their usefulness. In engines, that occurs as component tolerances degrade and, as a result, performance suffers.
LUBRICATION
The study of wear control has been focused on lubrication, the simplest and least expensive wear control method.
In some lubricated systems, such as the journal bearings in automotive engines, a lubricant separates component surfaces during normal operations. Surface high points travel through the lubricant film without touching the mating surface.
Any fluid that tolerates the operating environment and resists being squeezed out from between the lubricated surfaces (a function, in part, of viscosity) may be used to inhibit wear in this kind of lubrication, called "hydrodynamic lubrication."
Other lubricated systems, such as the cams and followers of the automotive engine valvetrain, depend on the lubricant's additives for wear control. Anti-wear additives either coat the component surface of the chemically interact with the surface to form a protective shield. Often, the chemical shield is removed by contact and is constantly replenished as the components are splashed with lubricant in this kind of lubrication, called "boundary lubrication."
Sometimes, such as during engine startup, hydrodynamic systems operate in boundary lubrication conditions. While at rest, a journal bearing shaft rests on its bearing. At startup, the shaft rotates against the bearing until a wedge of oil separates the shaft and bearing. Until separated, the shaft and bearing depend on anti-wear additives to provide a chemical shield of protection against wear.
AMSOIL
If virtually any lubricant may be used for wear protection in hydrodynamic lubrication and presumably all motor oils contain anti-wear additives for boundary lubrication conditions, why use top-of-the-line AMSOIL synthetic motor oils?
-
Friction Control: As lubricants separate moving surfaces to minimize friction and wear, the layers of lubricant between the surfaces move against one another. A smooth, uniform molecular structure allows AMSOIL synthetic motor oil layers to slide easily over one another and consume comparatively little of the engines' energy. That keeps fuel consumption down and power up.
-
Film strength: strong intermolecular bonds make the AMSOIL synthetic lube film tough to break so that even during sudden load increases, the hydrodynamic film remains intact, which helps prevent catastrophic damage and wear.
-
Heat Control: heat can change the hardness of sliding surfaces. Because the quantity of material lost to wear is influenced by surface hardness, heat control affects wear control. AMSOIL synthetic lubes keep heat and wear low.
-
Viscosity retention: effective hydrodynamic lubrication depends on the lubricant maintaining its viscosity within a narrow range. However, cold raises viscosity, impeding lubricant flow, while heat reduces it, impeding the formation of protective films.
AMSOIL synthetic lubricants maintain excellent fluidity in cold temperatures and full, protective films in heat. By so doing, they minimize the time hydrodynamic bearings spend in boundary lubrication after startup and minimize the risk of component contact during high temperature operations.
