Scott "Elder" Harrison
"Growing old is mandatory, growing up is optional"
Staff member
Contributing Member
OILPart 1 of 4
or
"One Slippery Subject"
In this series of articles I will cover mineral and synthetic motor oils, how we get it, what do the ratings means, what additives help, which oil you should use in what engine, transmission, and or rear axle; plus a couple of other topics thrown in for good measure.
A wise man once said, "There are three things you should never argue about, religion, politics and oil!" I have followed that advice until now. In the automotive world there is probably no other topic that will generate more opinions than the topic of "oil", what it should be and which to use, and so on. Some have challenged me to write about oil, now my years of "wisdom" have given me the thick skin to resist such challenges. But, when Jim Chichi "Double dogged dared me" to write about the subject, I could not ignore him. Although "Lord Knows" I've ignored him in the past, for some reason this time he got to me. I'll start with information hardly anyone could debate, then move into more controversial areas.
We all know how to get oil out of the ground, just like Jed Clampett did on the Beverly Hillbillies. But what do we do with it once we "gather" it up. One thing to do is to heat it. When a certain amount of heat is applied to crude oil, the lightest and most volatile part boils and passes off as vapor. This vapor, collected, cooled, reduced to liquid form (for those of you from Kentucky, think of a still) and subjected to further treatment, becomes gasoline. As the temperature applied to the crude oil is increased, the heavier fractions such as kerosene, gas and fuel oil, and lubricating oils are passed off in the same way the gasoline was. What is left is a final residue such as wax, coke and asphalt.
In an effort to educate you, all these products, are often called petroleum products, the word means "rock oil". Don't you feel smarter now?
So, remember that a barrel of oil has 42 gallons in it. Out of a barrel of crude oil we get, about, 17 ¾ gallons of gas and fuel oil, 17 ½ gallons of gasoline, 2 ¼ gallons of kerosene, 2 gallons of miscellaneous (don't you wonder what that is ?), 1 1/3 gallons of lubricating oil, 1 + gallons of coke and asphalt, and 1- gallons of wax. All that adds up to 42 gallons, plus or minus some.
Said in another way, when I change the oil my vehicle, in the winter, in my shop heated with kerosene, and fill up the gasoline tank after the oil change, it takes a barrel of crude oil to produce enough motor oil, kerosene, and gasoline to do the job. Kids, read that again, that is one barrel per one car!!!!
Back to oil as a lubricant. By definition, a lubricant is a substance used to reduce friction by preventing direct contact of rubbing surfaces, the substance being pressed out into a film on which the moving parts rub.
A desirable lubricant has the following qualities. 1. Body- the consistency of the oil that prevents it from being squeezed out from the rubbing surfaces. 2. Viscosity- refers to a certain lack of cohesion between its different particles, which reduces the fluid friction. 3. Freedom from gumming- a lubricant that gums loses its viscosity easily, collect dust and grit, and increases friction and wear. 4. Absence of acidity- a lubricant that holds free acid would attack the bearing surface. 5, Stability under temperature changes- a lubricant that is stable will retain their good qualities even when used under extreme temperatures. 6. Freedom from foreign matter- if a lubricant contains foreign matter, it will increase friction and clog the oil system. We tend to take these qualities for granted today because the major oil company's watch over these qualities for us by meeting industry standards, we assume all is good.
Using the proper oil in our vehicles is very important. The hardest working component in your vehicle is its oil. So which one is the best "oil"? Yeah, it's a trick question, there is no one answer. You have to answer a bunch of questions to narrow down to which oil is best for your application. How old is the vechicle, how much wear does it have, what sort of filter system, or lack of a filter system, does the drive components have bronze or copper alloy bushings, does it have flat tappets, what temperatures does it operate under, does it tend to run hot, how often do you change the oil, do you use additives or buy oil that has the proper additives, should you use multi-grade oils, does it have a wet or dry clutch, is it water or air cooled ? Wow, didn't know picking an oil was that difficult did you ??????
So, over the next four newsletter issues, I'll try to give you some answers to a few of these questions while educating you about "black gold" or oil. The hope is that you will have a much better understanding of what is required of the oil you pick for your vehicle, there by increasing the life of its engine and drive train.
Part 2 of 4
In Part 1 of this series we talked about the qualities of good oil, now let's look at the basic functions oil is supposed to do. These are certainly not in any order, but each function is very important. Your oil has four jobs. 1. Oil cools by dissipating and carrying away heat caused by combustion and the friction generated by parts moving together. 2. Oil also cleans by carrying contaminants produced by friction and combustion to the oil filter, if you have one, or the oil slinging rings or screen sump system. 3. Oil provides a film between moving parts to reduce friction. 4. The sealing properties of oil prevent it from leaking past seals and rings. A rubber seal cannot keep oil in or out without having a film of oil to assist it.
Also, in Part 1, we noted how oil is separated from its crude component by heat. This is fossil or mineral oil, the most natural of our oils available today. Most of us "grew up" using fossil oil or as some call it, dinosaur juice. Some of the purest oil in the world comes from Pennsylvania. The dirtiest is probably from Canadian tar sands in Alberta, with Texas and Middle Eastern crude in the middle. Not to worry, by the time fossil oil is suitably refined with additive packages to enter your vehicle, it is a long way from pure.
But, recently synthetic oils have entered the market. This man-made oil is synthesized from chemical compounds. The artificial lubricant substitutes wonderfully for crude mineral oil. In many ways synthetics provide superior mechanical and chemical properties. The origin of synthetic oils rests in the necessities of Germany and America during World War II. Especially in Germany, the lack of follized oil in its territory meant something else was required to indefinitely drive its war machine. The superiority of synthetic oil made for reliable airplane engine maintenance and durability. It was the mid-60's when synthetic oils where first marketed for our use. Chevron was probably the first to do this.
Again, in Part 1, we listed all the qualities of good oil. The one we are most familiar with is viscosity. What is viscosity? Viscosity indicates resistance to flow. The smaller the number the thinner the oil and easier it is to pour. This way, 20 weight oil is lighter than 50 weight oil. Too thin an oil will not maintain a film on components. When oil becomes hot, flows more easily and effectively becomes thinner, component protection is reduced. The Society of Automotive Engineers (SAE) in America devised a viscosity index and special apparatus was produced to measure flow. A special amount of oil is heated to a precise temperature in a container. The heated oil is allowed to drain through a hole in the bottom of the container and the time to drain it completely is measured. Weight values are assigned depending on how long each oil takes to empty the heated container. You are familiar with these numbers as they are the values, 10, 20, 30,......90 and so on we see marked on the container that oil is sold in. These are the numbers we call straight grades. By the way, I've seen oil with SAE grades of 1400, but after about 600, the oil is for steam engines and much more than that it is really liquid grease. For your information, grease, as we know it, is standardized and classified by the NLGI (National Lubrication Grease Institute) and uses a different numbering system, maybe I'll do an article on grease someday (won't that be exciting).
Oh yeah, I digress, back to oil.
Remember, when oil gets hot, it gets thinner and loses its ability to protect your machine. This is why multi-grades were developed. They become thicker as they warm up to maintain a protective film. They are suitable for a wide range of temperatures and can cope with winter, summer, low speed and sustained high speed work. They do this with the addition of additives to a straight oil. The additives in the blend provide this versatility. In fact, some oils can have up to 25% of their volume provided by additives. The wider the grade swing, the more additives, that is, 10w40 has more additives than 10w30. Some feel that the wider the grade swing, the more additives, the more the oil has a tendency to "sludge".
Multi-grade oil is typically listed as 10w40, 20w50, etc. The letter "w" stands for winter not weight. Thus for cold starting and quick warm up a 10w50 multi-grade moves with the viscosity of a 10 weight when cold, but when it gets hot, it thickens like a 50 weight oil. This actually works, I remember an experiment from my early engineering classes were we did this, measure the multi-weight oil cold then hot, it was amazing how it changed. In fact, that experiment is about the only thing I remember from all my schooling !
Multi-grades were introduced in the early 1950's and became popular partly because of their convenience. They eliminated the need to change oil from a lightweight (low viscosity index) oil for the winter use to a higher weight (high viscosity index) oil for the summer use.
When it comes to oil viscosity, my recommendation is the stick with the weight recommended in your owner's manual, whether it is straight or multi-grade. Or, use the grade of oil recommended during the last production dates of your engine type, the manufacturer may have switched from single grade to multi-grade during that period.
This is antidotal information, but even though I have seen the multi-grade oil change weights with the temperature, I have also seen, in more than one vehicle, the oil pressure drop, with the motor hot, when I went from a straight 50 grade to a 20w50 grade. That being said, I still use multi-grade in some of my older vehicles. It sure does make starting easier.
Hang on for next issue, we'll learn about the American Petroleum Institute (API) oil classification system, Group I to Group V and the API rating letters, SA to SM as well as the "C" rated oils. In the mean time, go check your dip stick.
(cont'd below since posts can't exceed 2000 words.)