The last issue of maxxTORQUE Lube Notes explained the regimes of lubrication including Hydrodynamic Lubrication, Boundary Lubrication and Elastohydrodynamic Lubrication. As promised, I will now talk about the formulation of motor oils and why we put all those additives in our oil. Before we get into the formulations of the motor oils, we better take a look at the functions of motor oil. If we understand what oil is doing, then we can better understand why we choose certain base stocks and additives.
Motor oil must perform the following functions:
Lubricate engine parts in order to prevent wear
Reduce friction and improve fuel economy
Maintain clean engine components
Prevent rust and corrosion
Minimize engine deposits
Provide engine cooling
Aid in engine starting
Provide ring seal for better combustion pressure
Each of these functions is vital to optimum performance as well as to the durability of the internal combustion engine. Motor oils are complex lubricating fluids carefully formulated to perform all of these functions.
The LMM Duramax is certainly a step forward in its reduction of emissions into our environment. These controls, however, come at a cost. In Learning to Love the LMM Duramax Emissions System, Joel Paynton looks at what the LMM accomplishes and what it costs in terms of convenience and fuel economy. In this article, I want to take a quick look at what recycled soot does to the engine oil in the LMM and recommend bypass oil filtration as a worthwhile protection for this considerable investment.
Oil bypass filters for large diesel engines are accepted as a necessity and have been recommended by several aftermarket filter companies for many years. As a certified lubrication specialist, I have recommended bypass filtration systems as a solution for many diesel applications, though not for every application. Prior to the LMM, the Duramax engines were capable of dealing with soot. Even if they could benefit from a bypass system, they could certainly get by without one. Not so with the new LMM. I absolutely recommend bypass filtration for this engine.
September 2008, Bill Heath raced the Heath Diesel Team’s 6.5L GM Diesel pickup at Bonneville. maxxTORQUE featured the vehicle in our Summer 2008 issue before the event. Now, here is a look at the Bonneville performance and what’s inside that makes this truck – that could pass for a daily driver – fast...
Heath Diesel Power’s 6.5L GM Turbodiesel Land Speed Racing truck ran a solid 153 MPH on its first trip to the Bonneville Salt Flats – that felt pretty darn good. Knowing that she has more speed in her yet – that’s even better. Here’s a look at our experience at Bonneville and the details of the build that got us there...
The ongoing march to achieve more technologically advanced engines continues and certainly the GM Duramax diesel engine exemplifies that quest. The race between GM and its would-be competition has benefited you and me: the improvement in all aspects of these diesel engines is easily quantifiable in terms of horsepower and torque as well as fuel efficiency and endurance. Recognizing how vastly improved these diesels are to their predecessors, it should not surprise anyone that advances in the lubricants for these engines have also facilitated quantum leaps in performance.
Any oil, properly rated for use in a high performance turbo-charged engine, is a remarkable lubricant regardless of the base oil used. In this article, I will compare synthetic diesel engine oil to petroleum diesel engine oil and draw some conclusions and make some recommendations. Previous Lube Notes have established fundamentals of lubrication and how oil is made, so if you haven’t read those, a review might be in order. I am writing this article assuming you have read the preceding articles.
In previous Lube Notes we looked at the role lubricants play in overcoming the effects of friction. In this installment, I want to examine one specialized type of lubricant: grease lube. Looking at previous civilizations, we can see that man has tried several methods to provide basic lubrication to load-bearing surfaces; axles have presented one of the most challenging applications. As far back as 1400 BC, mutton fat and beef tallow were used on chariot axles to reduce friction in order to allow for more speed and to slow down wear. One can only imagine the pressure on the maintenance men to make the chariot go faster and to avoid axles catching on fire from the continuous friction. While there is evidence of lime being added to these fats in order to make their lubricating properties last longer, few other improvements to the composition of grease are known to have been used until we reach the magic year of 1859.
In previous Lube Notes we looked at the role lubricants play in overcoming the effects of friction. In this installment, I want to examine one specialized type of lubricant: grease lube. Looking at previous civilizations, we can see that man has tried several methods to provide basic lubrication to load-bearing surfaces; axles have presented one of the most challenging applications. As far back as 1400 BC, mutton fat and beef tallow were used on chariot axles to reduce friction in order to allow for more speed and to slow down wear. One can only imagine the pressure on the maintenance men to make the chariot go faster and to avoid axles catching on fire from the continuous friction. While there is evidence of lime being added to these fats in order to make their lubricating properties last longer, few other improvements to the composition of grease are known to have been used until we reach the magic year of 1859.
What happened in 1859? Colonel Drake drilled the first ever oil well in Pennsylvania; since then, the world has not been the same. In petroleum oil, man found a lubricant that could be manipulated in a variety of ways to produce greases much superior to the lubricants that preceded them. In turn, more advanced and effective greases have been produced in recent decades with the advent of synthetic greases.
The word grease is derived from the Latin word crassus meaning fat. We can see where the name came from (mutton fat, beef tallow); however, grease lube, for modern purposes, is not to be construed as fat. The American Society for Testing Materials (ASTM) defined grease in 1916 as: A solid to semi-fluid product of dispersion of a thickening agent in a liquid lubricant. In plain English, this means A lubricant composed of lubricating fluids (oils), thickened by mixing chemicals to produce a semi-fluid to semi-solid consistency.
Some time ago, there was a love-hate relationship with the Clean Air Act and many mechanics and owners who tended to view diesel engine emissions controls as evil. That was because most carburetors and vacuum control systems were not terribly reliable: as a result, fuel economy and survivability suffered. Entering the 80’s and the era of fuel injection, emissions systems suddenly became more reliable and usually improved the overall performance of an engine; at the very least, they did not hinder it. Computer controls allowed for much more precise engine operation. Despite this, diesel engine emissions controls sometimes still have that original stigma attached to them. In the early years, people often solved their drivability problems by removing all the emissions controls, retuning the engine’s performance – and pollution output – to pre-emission levels. This was illegal then, of course, and remains illegal today even though some people still remove EGR valves and catalytic converters.
In the preceding Lube Notes, we covered basic lubrication, oil functions, additives and base stocks. Now, it’s time to construct finished lubricating oils. From what we have learned, it may seem like the only thing we need to do is pick a base stock oil, mix in some additives and presto, we have lubricating oil. If only it was that simple. Of course, it’s not.
Previously, we looked at the refining of petroleum and classifications for synthetic and petroleum oils. The base stock with which we choose to start will obviously have a direct bearing on the quality of the finished product. If cost is no concern, then all finished oils would be made using one of the synthetic base oils since they result in the best lubricating oils. However, cost is an important factor and will always be a consideration in choosing base stock oils. Most oils are manufactured by a reverse process where the final performance requirements dictate the quality or lack of quality of the ingredients. If the manufacturer is making an oil to meet the minimum performance criteria for the current classification, then no money will be spent on anything more than an adequate base stock. On the other hand, if the manufacturer is producing a high performance oil, then he will spend what is reasonably necessary to produce the final product’s higher level of performance.
If you read the first two installments of Lube Notes, you have probably come to realize that I am gradually equipping you to evaluate lubricating products including a comparison between synthetic oil vs conventional oil. I am convinced that understanding some basic principles of lubrication can free us from believing everything that we read or hear. In this issue, I will briefly explain how petroleum oils are refined, introduce synthetic base oils and explain motor oil’s classification system used to assign quality levels to finished base stocks.
Petroleum Oil
Crude oil, truly today’s black gold, comes from nature as a dirty blend of hydrocarbons and contaminants of every kind. The job of the refinery (see figures one (page 17) and two (page 18)) is to clean this mixture and then crack it into various fractions for specific use. Crude oil typically comes with inorganic salt crystals and water mixed into the oil. It is necessary to remove this salt and water. This removal is accomplished by adding even more water and then allowing the crude mixture to settle. The oil is then heated by a large furnace until it becomes part semi-fluid and part vapor. This mixture then proceeds to the atmospheric tower, the heart of the refinery. The semi-fluids become asphalt and other derivatives while the vapors condense at various levels in the tower depending upon molecular weight. The portion of the vapor with lower molecular weight separates immediately, including kerosene and diesel. While diesel is derived from the first stage of the refining process, today’s ultra low sulfur diesel requires an extra step to remove sulfur (this step seems to be an excuse to raise the price). Vapors with higher molecular weight must go through an additional process to further crack – or separate – the oil into a greater variety of components or fractions as they are called. Lubricating oils – the fractions with which we are particularly concerned – are made from these latter, heavier fractions of the crude remaining after the gas oils have been removed. (Of note, recently refineries have developed methods to effectively use the heavier lubricating oil fractions for making gasoline. This competition for the portion of crude oil that previously was only usable for lubricating oils is one of the reasons for the rapid rise in the cost of petroleum lubricating oils.)
Crude oils from different regions of the world can be different with some being naphthenic and paraffinic. The paraffinic are much better feed stock for lubricating oils. Naphthenic oils contain no wax and are superior in cold flow applications. All crude oils contain roughly the same mix of hydrogen and carbon: 83 to 87 percent carbon and 11 to 14 percent hydrogen. Oxygen, nitrogen and sulfur round out the elements, with various metallic compounds also trapped in the oil. When dealing with lubrication qualities, it is important to consider the variation of molecular structure – from one molecule to the next – within the same sample of crude. Paraffinic molecules come in various carbon and hydrogen combinations to be sure, but to grasp the near-infinite molecular arrangements, consider a typical oil molecule of 25 carbon and 52 hydrogen atoms: this compound can occur naturally in any of 37,000,000 different molecular arrangements.
