Equipment World Digital Magazine
Issue link: http://read.dmtmag.com/i/885126
October 2017 | EquipmentWorld.com 26 is external contamination in the form of dust and dirt sucked into the engine each minute of opera- tion through the air intake. Particle contamination can be lethal for en- gines – even microscopic particles no bigger than a red blood cell can result in a significant reduction in an engine's life expectancy." Barnes added that many engine OEMs, like GM and Cummins, have proven that particles smaller than 10 microns are three times more likely to cause wear in criti- cal piston rings and bearings than larger particles (see Diagram 1). These particles – a tenth of the size of a human hair – can easily pass through the air filter into the engine air intake manifold. Motor oil deterioration According to John Baker at Amsoil, "Motor oil deteriorates and becomes unfit for service due to accumula- tion of contaminants in the oil and chemical changes (additive deple- tion and oxidation) in the oil itself." He points out the various con- taminates and their sources in the AMSOIL.com Blog: Abrasives • Dust and dirt. They can infiltrate engines via air cleaners, oil fill caps and crankcase ventilation systems. Proper engine mainte- nance is required to minimize the number of contaminants entering the lubrication system and extend engine life. • Metal particles from normal en- gine wear, as well as road dust particles and dirt. These can be picked up and circulated through the engine by oil and cannot be entirely removed by oil filters. Combustion by-products • Water vapor and steam produced by combustion when engine temperatures are high. They exit through the exhaust, condense into liquid at low engine tempera- tures, such as startup, warm-up and short trips, and enter the crankcase oil, leading to sludge and corrosion. • Acids produced through the combustion process. They find their way into the crankcase oil, combine with water and lead to corrosion. • Soot and carbon. They are pro- duced via incomplete combustion when engines are running too "rich" or with too much fuel and increase contaminant levels. • Fuel dilution that decreases oil strength and increases oil con- sumption when an engine is started or running abnormally. This results in unburned fuel de- posits on the cylinder wall. This leaks past the rings and into the crankcase, where it reduces oil viscosity and can be a significant problem in vehicles consistently used for short trips. Shelf life With reciprocating and slid- ing components, lubrication is a vital fluid to engine efficiency and longevity. Like blood, lubrication does not have infinite shelf life. Most lubricants have recommended shelf lives based largely upon the lubricant's additives. For example, maintenance | continued Oil analysis labs can detect minute amounts of contaminants that often give early warning about engine problems, such as faulty fuel injectors, coolant contamination and additive depletion.