Only one type of contaminant left to discuss: combustion by- products. These little buggers can wreak havoc in an engine. Not only can they form deposits on the inside of an engine which will rob it of performance and, ultimately, life expectancy, they will also tend to raise the acidity of the lubricant.
Higher acidity levels in your oil can lead to severe corrosion and break-down of engine components. In turn, this break-down leads to more oil contaminants and the necessity for an oil change.
Three things keep these contaminants in check: the TBN of the oil, high efficiency oil filtration and tight ring seal. The most important of these three is ring seal. If the number of combustion by-products entering your oil can be reduced, there will be less necessity to remove or neutralize them.
Poor ring seal allows combustion by-products to pass from the combustion chamber into the crankcase where they contaminate the oil. Tight ring seal keeps them out. Synthetic motor oils encourage a tighter ring seal than petroleum motor oils do.
As we discussed earlier, TBN (total base number) is a measure of how well a lubricant can neutralize acidic combustion by- products. The higher the TBN, the better the protection against these acidic by-products and the longer that protection will last. Hence, the possibility of longer oil drain intervals with oils that have high TBN values.
Oil filtration is the last component that must be discussed when making the case for extended oil drains. The next section in this series addresses this critical component.
---------------------------------------------------------------- Excerpted with Permission from "The Motor Oil Bible" eBook Copyright 2000 Michael Kaufman ("The Motor Oil Bible" Author) Download it from: http://www.motor-oil-bible.com ---------------------------------------------------------------- Part 5 Engine Wear Particles Cause Oil Contamination - Part 7: Efficient Oil Filtration Recommend Next
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