Measuring Lubricant Quality

Is there anything in today’s society that isn’t measured? We measure opinions, water quality, temperatures, economy, growth, statistics, speed, age… this list can go on and on. Americans love to measure their cars. We measure its speed, power, shine, age, distance traveled, its fuel consumption, even the loudness of their sound systems.

We measure power through units of horsepower, a unit invented by James Watt, the creator of the steam engine. He concluded that the average horse can lift 550 pounds at the rate of one foot per second, which is 745.7 watts.

Our fuel economy is measured by miles per gallon, or mpg. This is measured by the distance a car can travel on one gallon of gas. In countries that use the metric system, this is measured by kilometers per liter. One factor that directly correlates to your mpg is your mph, or miles per hour. Mph is the measure of your speed. This is measured by calculating how many miles you can travel in an hour at a given rate of motion. Like with economy, in metric countries, this is measured by KMH, or kilometers per hour.

Another measure used in the automotive industry is your engine’s rotations per minute. This is a very important measurement actually, because a car’s engine is designed to perform at its peak at a specific range of rpm's. Also, this is used to calculate shift points and fuel economy. If an engine’s rpm's get too high, it can lead to engine failure. Why is this? Because some parts of the engine just weren’t designed to operate at those speeds and, also, because of the lack of oil getting to those parts, which is why performance cars need quality oils. As a matter of fact, we have measurements for oils as well.

One of the most basic measurements of oils is the volume it takes up. Usually, oil is sold to the consumer in quarts, which is a quarter of a gallon (32 oz.). But before oil gets to the store shelf, it is sold in much larger quantities.

Crude oil is measured by barrels. A barrel of crude is 42 gallons. This crude oil is then refined and made into different products. The crude oil that is processed into motor oil is then sold as drums, or 55-gallon units. Most automotive service stations, especially lube shops, buy and use the oil out of drums. But the average consumer, who has no need for 55 gallons of oil, usually purchases oil by the quart. But as I mentioned earlier, performance vehicles require high-quality oil. How do we know how good the oil we put in our cars is? Well, we have a measurement for that, too.

To help us better understand what to test for in the quality of motor oil, we need to understand the most important functions of that oil. At a glance, it seems obvious: Motor oil is there to lubricate and cool the engine. How the oil goes about accomplishing that very important duty is more complicated that one may think. Your car’s oil is stored in a reservoir called the oil sump, or pan. In that area, a pump resides, where it sucks oil from the reservoir and pushes it through all of your engine’s passages that carry lubrication to the internal moving parts. While that oil is lubricating, it is also absorbing heat, cooling your engine. The oil is then cycled back to the sump, where it cools and starts the cycle again. In the early age of motor transportation, motor oil was actually made of the byproducts left over, after the crude oil had been processed into whatever else it could be. The oil was dirty coming off the shelf, compared to today’s standards. The filtration systems were less than adequate, if existent at all, and oil changes were very, very frequent.

As technology progressed in the automotive industry, the oils had to adapt to be compatible. During the Vietnam War, jetfighter crew members came to rely on the performance provided by synthetic oils. Synthetic oils flow better through the lubrication system and perform their functions better than conventional petroleum oils. One such crew member, a pilot named LTC Albert J. Amatuzio, brought the benefits of synthetic lube to the commercial sector and developed AMSOIL, the first synthetic motor oil that surpassed American Petroleum Institute certification requirements.

Comparing Conventional Oils to Synthetic
Take a jar and pour milk, water, and cooking oil in it. Let it sit for a few hours, and you will see that each type of liquid has separated and formed its own layer. Your motor oil is made with a very advanced form of the same process. Crude oil is refined, or separating the oil from the impurities within it. The different molecular structures are separated by weight producing different products with different characteristics. Since a specific weight doesn’t belong solely to one type of molecular structure, there is a large array of impurities hanging out with the desired molecular compounds, which is a hindrance to performance.

The only way to completely eradicate impurities is to chemically design and produce a pure product. Yes, a pure product. The purity is achieved by using chemicals and their reactions to molecules to obtain only the desired product. The molecular uniformity of oil produced this way greatly reduces friction, which, in turn, improves fuel economy and engine longevity. Take temperature. For instance, when it is hot, synthetic oil does not get thin, and the performance of your oil is not affected. When it is cold, conventional oil thickens because of impurities, called paraffin. Synthetics have no impurities.

So How Do We Measure the Quality of Our Oils?

There are standards put forth in the oil industry by the American Society for Testing and Materials (ASTM) that must be met to receive certification. The ASTM was created in 1898 and has become an association recognized worldwide. They currently have over 130 technical committees covering industries like metal production, oils, and environmental. They have devised standards that oil companies meet for performance in specific areas or lubrication. Using an oil that is rated by the ASTM standards is important, because 20% of consumer-level oils perform below the standard for which they state they perform.

For example, the ASTM D-5293 Cold Crank Simulator Apparent Viscosity Test tests the ability of the engine’s starting capacity at cold temperatures. Low-temperature viscosities make starting the engine in cold weather easier, due to the retention of its designed flowability. Cold-temperature viscosity is detrimental to cold weather starting because the battery is already weaker than it is designed to be, due to the frigid temperatures.

Another test is the ASTM D-97. This test measures the pour point of oil. The oil’s pour point is the coldest temperature at which the oil will still flow.

The ASTM D-4683 is the High Temperature, High-Shear Viscosity measure. What this measures is the ability to sustain the viscosity of the oil in higher temperatures when being exposed to high shear. A higher score in this test means that your engine's most stressed and heated parts will stay protected even under severe conditions.

ASTM’s D-4172B Four Ball Wear Test includes three fixed balls immersed in a lubricant, with the fourth ball rolling on the three with a specific pressure. The performance of the oil is measured by the scarring on the surface of the balls. Obviously, the less severe the scar, the better protection offered by the lube.

When oil is sloshed around and shaken, air can become trapped in the oil, causing it to foam. Air is then carried through the lubrication system and can cause damage, because air doesn’t have lubricating properties. The ASTM D-892 standard is the measurement of the oil’s capability of resisting foam, or excessive air trapped in the oil.

One thing that many consumers do not consider is the oil’s flash point. The flash point is the temperature at which the oil ignites with a flame. This is determined by the ASTM’s D-92 Flash Point and Fire Point test. The fire point is much like a flash point, except the ignition must burn for at least five seconds. Synthetic lubes are far superior to conventional petroleum oils because of their high flash and fire points.

The SAEJ1321 Joint TMC/SAE Fuel Consumption Test Procedure – Type II is the test that measures fuel consumption. In a test that was conducted using trucks that delivered freight cross-country, it was decided that the switch from conventional to AMSOIL synthetic lubricants improved fuel economy by 8.2%, when a truck typically can consume 100 gallons in a day, which is about a $24-a-day savings.

Finally, there is ASTM’s D-5800 Noack Volatility test. This tests the oil's resistance to boiling at high temperatures. At high temperatures, oil boils off, resulting in a loss of oil and also leaving sludge behind. The D-5800 Noack Volatility test measures oil’s resistance to boiling off, causing engine oil loss and creating sludge.

Synthetic oils perform better in all of these tests than their conventional counterparts. You would think that with all of the performance benefits of synthetic oil, that they would have already replaced conventional oils. The only hindrance to that fact is price. When you compare the price of an oil change using conventional oils, the difference might be as high as $50.00. The initial impact the price of synthetic oil has usually provokes people into sticking with their cheaper conventional oils, not realizing the long-term savings of synthetics. In the long run, using synthetic oils actually saves the consumer money, especially when you consider fuel consumption, engine repairs, and most importantly, oil life. Most people know they need to change their oil every 3,000 miles or three months, whichever is first. With a synthetic oil, that is not true. Synthetics hold up much longer due to the way they are designed and produced. They do not have the impurities that break down conventional oils and degrade performance.

When you consider the long-term price of oil, using a synthetic is the only sensible choice available. Choosing the best motor oil for your application is very important. Some oils perform better in hot weather, others in cold. Synthetic oil is the only choice that will outperform conventional oils in every measurement.