Today’s engines are smaller, lighter, and produce more horsepower per cubic inch than ever before, yet contain less oil volume, which puts the most strain on engine oil.

Power-boosting additions like turbo charging and super charging have become commonplace. Add in increasingly stringent emission controls with the stop-starts common in today’s congested cities and you have operating conditions that are tortuous for your cars’ motor oil.

So what qualities does motor oil need to have in order to survive these conditions and still provide adequate protection? As they say, “the devil really is in the details” when it comes to properly formed motor oil.

We will start with problems related to viscosity. A good motor oil must be able to maintain a constant viscosity when exposed to changes in temperature. It is also very important that the oil be able to maintain its proper viscosity throughout the intended drain interval.

The pour point of an oil tells you how well it handles cold temperatures without freezing (solidifying). Oils that contain too much paraffin; A wax found in petroleum motor oils tends to gel at low temperatures. Oils with poorly designed additives or poor quality viscosity index improvers will also have this problem. Modern engines have tight tolerances and need an engine oil that flows quickly at low temperatures to minimize wear at startup.

Tip: Look for oils that have low points. The pour point test determines the lowest temperature at which a lubricant flows. The lower the point of a lubricant, the better protection it provides in low temperature service.

At high temperatures and pressures, motor oil must be able to resist shear forces. The condition known as shearing is where the oil is literally torn apart on a molecular level, causing it to fall out of its proper viscosity range (example: a 40wt oil shears in the 30wt range)

This brings us to the topic of volatility and heat-related deterioration. At high temperatures, the lighter components of an oil can volatilize and evaporate. This is especially true of petroleum-based motor oils that have a mixture of hydrocarbon molecules of various sizes. At high temperatures, the lighter parts boil off leaving the heavier parts. This causes a gradual increase in viscosity and leads to accelerated wear, sludge and deposits in the engine. The ability to resist shear and volatilization is especially important in turbocharged applications where the oil passes through the turbochargers and the bearings are very hot.

Fully synthetic motor oils made from polyalphaolifin, a man-made molecule, have a uniform molecular structure that is much less volatile at high temperatures, making them ideal for high-temperature/turbocharged applications.

Volatility is measured by an industry test called the NOACK volatility test and is measured in percent weight loss. Good oils will show a loss of 10% or less on this test.

Synthetic motor oils are often less than 8% loss and some less than 5%.

Tip: Shear stability testing is performed by the ASTM High Temperature/High Shear Stability Test (ASTM HT/HS Test).

A test result greater than 2.5 is considered very good. Results greater than 3 are exceptional.

Tip: Look for oils with higher flash/fire points. The flash/fire point determines the lowest temperatures at which the application of a flame will ignite lubricant vapors (flash point) and sustained combustion for five seconds (flash point).

with higher fire and flash points tend to exhibit more stable volatility characteristics.

Wear control is one of the important things that people often consider when choosing a particular motor oil to buy.

Engine oils’ first line of defense against wear is their initial viscosity. Like any other liquid, oil is not compressible. Having the oil film between two moving parts itself prevents wear. However, under increasing load, at some point the oil film will fail, allowing metal-to-metal contact and wear. This is known as a “boundary lubrication” situation. (Note: Synthetic oils offer an average ten times higher film strength than typical petroleum oils)

To prevent contact between moving surfaces under these conditions, engine oils contain anti-wear additives such as zinc, phosphorous and calcium. These act to form a sacrificial layer that prevents metal-to-metal contact.

Higher quality motor oils generally have higher treatment levels of these anti-wear additives. However, it should be noted that simply having large amounts of these ingredients does not guarantee better wear protection. The quality of the anti-wear additives is of equal importance.

The antiwear performance of an engine oil is tested by the ASTM 4 ball wear test. 3 steel balls are immersed in the oil to be tested and a fourth ball is rotated against them at a given temperature and pressure for 1 hour. At the end of the hour, the 4 steel balls are removed from the test apparatus. The scars on the balls where they were in contact are measured and averaged. The smaller the size of the wear scars, the better the oils’ wear-fighting ability.

Tip: Look for motor oil that performs well in the ASTM 4 ball wear test. Using scars less than 0.050 inches is very good. Use scars .045 inches or less are rare. Scars less than 0.040 inches are outstanding. Note: Many oil companies do not publish ASTM 4 Ball Wear Test results for their oil, although some do, notably; Amsoil Inc., which publishes full test results for all of its products.

The next thing to consider is the ability of motor oils to control acid formation and maintain engine cleanliness.

The acid fighting ability of a motor oil is expressed as TBN or total base number. The TBN number is a measure of the reserve alkalinity of motor oils. As the miles go by and the hours of oil use are added up, this number usually goes down, which means the acid-fighting ability is being depleted.

Motor oils designed for use at OEM change intervals will typically have a TBN in the range of 7.5 to 8.3. Synthetic motor oils that offer drain intervals greater than 10,000 miles will often have TBNs of 8.5 to 9. Very high grade synthetic motor oils such as Amsoil Long Drain; designed for up to 25,000 miles or one year, they have a TBN number greater than 12, giving them tremendous long-term acid-fighting ability.

In addition to controlling acid buildup, quality motor oils contain detergent and dispersant additives to control contaminants in the oil. Detergent additives prevent deposits, sludge and varnish from forming and sticking to engine surfaces and dispersants keep these contaminants encapsulated and suspended so they can be effectively removed by the engine oil filter.

Other parts of the motor oils additive package are there to prevent things like rust and corrosion from both combustion by-products and moisture and to prevent the oil from foaming under parts that are churning inside the engine. engine. Foam control is very important because oil that has a tendency to foam will have lower film strength and can even cause engine oil pump cavitation and loss of oil pressure leading to increased wear. .

Tip: Even if the motor oil packaging says it meets your car manufacturer’s specifications, lower-quality, cheaper motor oils generally have lower treatment levels and use lower-quality additives that wear out more quickly over time. the use. This leads to an engine that is dirtier, has more deposits, and shows more wear over time than the same engine that would use higher quality motor oil.

The best oil is one that offers exceptional wear protection, has a wide operating temperature range, and is shear and oxidation stable. It should also have a high degree of detergency to keep things clean and a great ability to fight acids.

Sound like too much to ask? Frankly, the biggest challenge for any oil manufacturer is to produce a balanced product. While it is relatively simple to design a motor oil that performs extremely well in a particular test, say the ASTM 4 ball wear test, it takes a lot more experience and expense to make an oil that performs well across the board. Experience counts when formulating motor oil!

So as you can see, modern engines put a lot of demands on their oil and choosing a very high quality motor oil makes a big difference in the long run.

Think about this. He had no control over how his car was designed. There is no control over the quality of the metal used to build it. There is no control over the workmanship of the people who put it together, but the quality of the oil, lubricants and filters you put in your vehicle is the only thing you have absolute control over!

Choosing the highest quality oil you can find that meets auto manufacturers’ requirements is the only sure way to maximize the life of your engine and get the most out of your automotive investment.

Amsoil Inc introduced the first fully synthetic motor oil that met the requirements of the American Petroleum Institute in 1972. Today, Amsoil is considered the world leader in synthetic motor oils and lubricants.