An primer on motor oil.

[Scott Harrison]

OIL
or
"One Slippery Subject"

Part 1 of 4
 
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.)

[Scott Harrison]

Part 3 of 4
 
OK, a quick review. In Part 1, we learned what a barrel of oil provides us and the qualities of good oil. In Part 2, we learned about the function of oil in our vehicles; fossil and synthetic oil; and single and multi weight oils. I hope you are remembering all this, for the test at the end of this series.
 
Also in Part 2, the American Petroleum Institute (API) was mentioned, let's continue there.
So who is watching over these oils to ensure uniformity and quality? Why it's the API !!! They have created a classification process to determine which oil is suitable for the internal combustion engine. Part of the classification system categorizes the different chemical base oils into API Groups I through V (for you non-Roman types, that's 1 through 5). Group I, Group II, Group II+, and Group III are mineral/ fossil oils. A Group III base mineral oil is sometimes classified as a synthetic, but officially remains the top fossiled (mineral) oil stock. They have a long explanation why this split personally, it deals with hydrocracking (who knew you could break water?!?!?). I'll not go into it because it's really boring ! Hold onto your socks for the next two groups. Group IV is a PAO (polyalphaolefin) base synthetic and Group V are non-PAO synthetic esters (diesters, polyolesters, polyglycols alkykalated napthylaminers and alkylated benzenes). Start throwing those terms around at your next get-together you're sure to be a hit. I know I wished I would have paid more attention in chemistry class. Just to confuse things a little before we leave API Groups, Motul introduced the first semisynthetic oil in 1966. Semisynthetic oil, also know as a synthetic blend, is more economical than synthetic oil and offers some of the advantages of the synthetics. These oils are blends of the mineral oil with a maximum 30 percent synthetic oil content. To be formal, synthetic blends are Group I to III mineral oils mixed with some (up to 30%) Group IV PAO synthetic oil. Just so you don't get too comfortable with all this, there are some manufacturers that use the Group IV PAO as the base stock and add a little mineral oil. Just like your momma told you, "there's no accounting for taste!".
 
Don't worry if you don't remember any of these classifications, we don't really go into our local auto store and order a Group III oil. But we do order API Rated oil, so let's look at this Rating System.
 
It all started long, long, ago, in a place far away, no wait, that's another story! It did start in the late 20's, there was little question about which oil to use, many because all that was available was straight petroleum. Then detergents were added, then more additives, soon multi-viscosity oils, then they started taking additives out of the oil, how can a person trust what is going into their vehicle? That's when API stepped up to the plate and started using their two letter service ratings to ensure oil met certain standards. For our interests, we will cover the service ratings that start with "S", "S' is for gasoline engines. The "C" rated oils are for diesel engines and "T" rated for two stoke engines. The following chart is for "S" rated oils, and slows the evolution of our oils over time.
 
API GASOLINE (S) RATED OIL CHART
 
API                 2010 Status                     Coverage                   Characteristics
 
S                      - -                                                                            Suitable for gasoline engines
SA                   Straight petroleum        1930 and back           "
SB                   Superseded                     1963 and back           "
SC                   Superseded                     1967 and back           "
SD                   Superseded                     1971 and back           "
SE                   Superseded                     1979 and back            "
SF                   Superseded                     1988 and back            "
SG                   Superseded                     1993 and back            "
SH                   Superseded                     1996 and back            "
SJ                    Current                             2001 and back            "
SL                    Current                             2004 and back           Reduced additives
SM                   Current                              2007 and back           Reduced additives
 
 
This is how API views our oils today, that is, a SM rated oil is good for everything back to the beginning of automotive history. This may not be true, and we will discuss some of the problems in later articles. But, rest assured that motor oils available today are far superior to anything that was sold when many of our antique and classic vehicles were new and on the road as everyday drivers.
 
The next time around, we will talk about oil additives, oil deletions, and some recommendations about the oil you use. So while you are waiting for this editorial masterpiece, go read an oil can, ah, bottle.



 
Part 4 of 4
 
In the first three parts of this series on oil, we learned about oils qualities, functions, weights, API classification, and API ratings. There was mention about how manufacturers put additives in, and now are taking them out. So, let's talk about what may be good or bad for your engine and drive train and make, dare I say it, some recommendations.

In the early days of oil technology, we had straight petroleum, refined as best as they knew how at the time. It worked OK on many plains, the ability to refine any better lubricant, the metals available to build an engine and drive train at the time, and the lack of any concerns about the environment, allowed that early oil to function as needed. As the clock rolled on, we got a lot smarter about refining, metals and what was required to protect our environment.
 
With the early straight petroleum, we used lightweight oil in the winter and heavy weight oil in the summer. Soon detergents were added, and then we had another choice, detergent or non-detergent oil. Because dirt and particle dispersants were added, oil filtration was improved from nothing, to a simple screen at the bottom of the sump or slinger rings, to the highly engineered filters we use today. Anti-rust inhibitors, anti-foam inhibitors, anti-oxidant inhibitors, and anti-wear inhibitors were added along the way. The ability of additives to make the oil thin when cold and thicker when hot gave us multi-grade oil, eliminating the need to change oil with the seasons. As better metals became available, clearances were made tighter creating more horsepower and the associated heat. The need to reduce pollutants expelled from our engines and provide better gasoline mileage required even tighter clearances and higher heat. All these reasons made the use of more additives necessary. Why today we have oils with a grade of "0", like in 0w40 weight oil
 
By the way, not everything was added into our oil, again as we got smarter, sulphated ash naturally occurring in the oil was removed or at the least significantly lowered. Remember when you used to tear an engine down and the inside was filled with sludge, no matter how well you had maintained the oil. That sight has almost disappeared today because of our modern oils.
 
 
All the above improvements have taken us from the early SA rating of oil to the SL rate of later years. But our early vehicles didn't have to worry much about the earth (environment) and certainly didn't have catalytic converters hanging on the exhaust system. The concern about meeting government standards for pollution has invaded our oil.
 
Today's API service SM gasoline engine oils are formulated with reduced amounts of anti-wear additive ZDDP (zinc-diakyl-dithioshoshape), say that fast three times. Both zinc and phosphate are key oil additive compounds that help prevent engine wear. But, they also contaminate catalytic converters when emitted into the engine exhaust. The long evolution of oil improvements has featured the concept of backwards compatibility. Said in another way, the latest grade of oil could be safety used for all engine requirements back through the years, according to the API. The word is that in the future, even more additives may be removed from our oil in the interest of the environment; this may or may not have an influence of the life of even on our modern engines.
 
After all this babble, the question still remains, which oil am I to use? Here comes the controversial part I promised at the beginning of these articles. I'll not give a bunch of reasons for my recommendations, or this article will have twelve parts instead in four. If you want reasons, write your own article!!!!!!
 
 
First, a disclaimer, "The recommendations are for vehicles with out a catalytic converter."
 
Change a mineral oil about every 3,000 miles or so
 
Use the weight, single or multi-weight recommended by your vehicles owner's manual.
 
 
Never use a thinner weight oil than recommended, do not use a heavier weight than recommended, if you have no oil pressure, rebuild the engine.
 
If you want to use an SM rated oil, add ZDDP, you can use ZDDplus, Cam-Sheild, Crane or General Motors EOS (which may have been recently discontinued). There are specialty oils like Morris Elite, Brad Penn, Castrol Syntec Classic (in the black bottle), Joe Gibbs Racing oil, Red Line, Valvoline VR-1, and certain AMSOIL oils that have the higher levels of ZDDP, when you use them no more additives are needed.
 
Some folks use a "Diesel-Rated " oil, such as Rotella and Delo that are rated CL-4, however, diesel oils are a mixed blessing. While some have adequate levels if ZDDP, they have other additives, such as extra detergents, which may cause other problems when used long-term in gasoline engines. If you do use a diesel-rated oil, do not use the new CJ-4 rated oil, it to has reduced levels of ZDDP.
 
Do not use an airplane oil in your vehicle, such as Aeroshell. Airplane engines have a different set of requirements therefore different levels of additives.
 
 
If your vehicle has no filter, or a screen or slinger system, use low dispersant, low detergent oil, like Morris Elite oil. Look for a API-SD rated oil. You want the dirt to fall out of the oil into the sump.
 
Do not use a synthetic oil during the break in period of your engine, if your engine was completely rebuilt, and the synthetic oil is available in the correct weight, than use it after break in.
 
Do not change to a synthetic oil in a old engine that has used mineral oil for all its life.
 
Do not use a synthetic oil if you are using lead in your gasoline. Synthetic oil does not suspend lead dirt in the oil until it gets to the filter very well.
 
Do not use synthetic oil if your vehicle has a wet clutch. The "jury" is out on this one, but I would rather err to the safe side.
 
Synthetic oils do have a much longer change period, some say as much as 7,000 miles between changes. I don't run them much longer than 5,000 miles in my new vehicles. Dirt in your oil is dirt in your oil, no matter what oil you use, the filter does not remove all dirt.
 
If your vehicle has any bushings made from a copper alloy, such as Phosper bronze, bronze or brass, popular in old transmissions and rear axles, do not use gear oil that contains EP (extreme pressure) additives, they can chemically corrode these components.

Submitted by Van Webster, President
Susquehanna Valley Vintage Sports Car Club a Region of the AACA.

Fine Print
This information may or may not be true. Van is not always right, in fact, most of the time "HE IS NOT RIGHT"! Some have said that he is "two sockets short of a full set" Use your best judgment when making decisions about your vehicle, because Van won't stand behind his advice!