The need for lubrication is basic. Every owner operator worth his salt takes care to protect his livelihood with frequent oil drains. But new oils come out often, making it difficult to keep pace with oil technology. Is it enough to maintain regular oil drain intervals without considering the characteristics of new oils?
The need for lubrication is basic. Every owner operator worth his salt takes care to protect his livelihood with frequent oil drains. But new oils come out often, making it difficult to keep pace with oil technology. Is it enough to maintain regular oil drain intervals without considering the characteristics of new oils? Might you extend the life of your engine by switching from CH-4 to CI-4? What about CI-4PLUS? And what about the newest oil designation, DDC93K214, just out July 9th? To begin, what exactly do those letters and numbers really mean?
Alex Bolkovsky, Commercial Vehicle Lube Advisor, Exxon Mobil, says that the common oil designations were begun 50 years ago by the API, American Petroleum Institute, to keep track of changes in the composition of oils as they were developed and marketed. About 15 years ago, a further distinction was made between oil for gasoline engines and oil for diesel. The letter C became the designation for compression ignition, a diesel engine’s method of firing fuel.
Bohofsky continues, “The letters after the C are simply iterations. The API uses consecutive letters of the alphabet to label consecutive formulations. The number 4 simply stands for four strokes, which is the number of strokes in the combustion cycle.”
As for the PLUS, Chuck Blake products engineer at Detroit Diesel, says, ”The PLUS was added because Mack and Cummins wanted to add minor improvements to it.” According to an article in last November’s Lubes ’n’ Greases, another factor in the PLUS designation were last minute engine changes that oil suppliers had not been able to take into account. Despite this, Blake says,”CI-4 meets all the requirements of ‘02 standards for EGR engines without the Plus. When oil goes to J for ’07 engines, there will be a much more substantial upgrade.”
Dan Larkin, technical consultant and President of D&L Lubricant Solutions, adds, “PLUS is an adjustment to CI-4. It takes three or four years to develop an entirely new designation.” Larkin goes on to explain that oil designations are really a collection of tests. He says, “Every new designation has more restrictive testing.” The PLUS designation includes a stricter shear stability bench test, International’s 6.0, and the new Mack T-11 test for soot-viscosity that is also more demanding than the older Mack T-8E test. Shear stability tests determine which metals and how much of them are in oil while soot-viscosity tests provide data about soot rates and how much oil is thickening.
Detroit Diesel’s new 93K214 specification, “is meant for use in model year 2002 and newer Series 50 and 60, and MBE 900 and 4000 engines in on-road applications. The specification is also applicable for use in pre-2002 model year engines,” according to a letter from Detroit Diesel addressed to its customers. In this letter, Detroit Diesel says it has decided not to use API engine oil specifications. “The current service category forms the core of the new 93K214 specification.” But, “Additional requirements are necessary for newer emission controlled engines.” In addition, “The significant presence of Mercedes Benz engines and the common practice of oil drain extension make the selection of the proper oil imperative to maximum service life,” the letter says.
Over at Cat, where ACERT technology rather than exhaust gas recirculation is in place, Mike Quinn says that Cat has also come up with its own specification, called ECF-1. ”ECF-1 includes all the tests in CH-4 and CI-4 but it has an additional test for piston deposits. There is lots of ash in CI-4 left over from additives as they burn during compression. We capped sulfated ash at 1.5 rather than the higher number used for CH and CI-4. This means we are in better shape for ’07 when ash and sulfur levels will have to come down.”
Oil standards from the API as well as from original engine manufacturers have been driven by Environmental Protection Agency requirements since CG-4. That’s when low sulfur fuel became required and engine technology changed to deal with this new fuel. Oil formulation also changed to continue protecting engines despite the lack of lubricity in low sulfur fuel. But new oil research has not always been driven by EPA standards. CE and CF oils were developed to lubricate engines which were then being engineered with more horsepower. Larkin says there was also a push to extend drain intervals at the same time, so the need for better oil was paramount.
However, previous oils are not necessarily taken off the market when a new one comes along. Oils all the way back to CF are still being sold. “CE is obsolete,” Larkin says. “But CF and CG are still being used in older engines and CH is still used in newer non EGR engines.” Larkin also notes that old two stroke diesels like Detroit’s 6V92 made use of oil specifically designed for them. After two strokes were no longer sold, the 2 designation for diesel oil was dropped.
It is likely that most owner operators are using CH-4 in their engines now. CI-4 and CI-4 PLUS oils will provide a safety edge, Larkin says, “There is a safety factor to these new oils for every user, not just those with EGR engines. CI-4 and PLUS do not add as much of a benefit to non EGR engines but if you develop a coolant leak or overheat or want to extend drain intervals, CI-4 gives added protection.” Larkin is conservative and believes that anyone who wants to extend his drain intervals should talk to his engine manufacturer and oil supplier before embarking on a program of extended drains. “If you’re sticking with CH-4, you need to keep a more careful watch on it, “he says. This is particularly true if you are in severe service or have a truck newer than ’97. Engines began to use retarded timing in ’98, increasing the need for quality lubrication. Larkin also says that if you have idle times above 30 per cent or haul heavy constantly and/or run the mountains, your oil will be depleted more quickly. “Hauling heavy creates more soot,” Larkin warns. “And idling puts more contaminants in the oil so that it doesn’t lubricate as well for the length of the drain interval.” In addition, CI-4 will provide protection if you happen to exceed your typical drain interval.
Dan Arcy, Shell Technical Expert, remarks, “Idling tends to go up given the new hours of service and it is also a factor to consider in ltl operations. Operators need to be aware that their engines are affected by type of service and even log regulations so that they can establish appropriate drain intervals.” Shell’s oiloil analysis program can be contacted at 1-800-231-6950.
What is it that makes CI-4 different from CH-4? According to Bohofsky, “Because EGR engines run hotter, CI-4 is formulated to handle the added heat stress.” When oil gets hot it oxidizes. This means the molecules of oil develop an extra atom of oxygen. This molecule with the extra oxygen is called a peroxide. Peroxides are known to attract chemical contaminants in the oil and degrade it. “CI-4 handles oxidation better than CH-4,” he says. “It keeps the oil from thickening.”
To do this, oil formulations began using higher quality base stocks and also incorporated more of some old additives and also put in some new ones. Arcy at Shell agrees: oil analysis shows that soot is up in EGR engines. But alkaline reserves are also dropping at a much faster rate. This means there is less alkaline reserve available to neutralize the higher acid content produced in EGR engines. CI-4 is formulated to counter these trends.”
EGR engines tend to have more acids since exhaust gases drop acids out when the gases are recirculated. So the total base number of CI-4 has been increased to neutralize more acid. “CI-4 also has more detergents,” Bohofsky notes. “Detergents help neutralize acids and they help control deposits as well.” EGR engines produce about 50 per cent more soot than pre EGR engines and EGR creates more particulates than pre EGR engines. Particulates are formed when fuel is burned at lower than optimal levels. The retarded timing of engines built from ‘98 onward adds to less complete combustion of fuel, which also creates soot. While EGR engines did reverse retarded timing somewhat, EGR continues to have more retarded timing than pre ’98 engines, making soot the most significant contaminant in the new engines.
Randy Dunn, an owner operator leased to Universal Am-Can, has just bought a nice red 379 Pete. It’s a ’97 with half a million miles on a Detroit Series 60 500 horse power plant. He is wondering whether to stick with the 55 gallon drum of Wolf’s Head in his garage or switch to another brand. He is entirely satisfied with the performance of Wolf’s Head, a Shell subsidiary popular in western Pennsylvania and New York State. “I’ve used Wolf’s Head for years,” he says. “But I’ve never had a Detroit before and I need to find out what they recommend.” The drum says Dunn has been using a CH-4 grade oil which should be fine for his pre EGR, pre- retarded timing, machine. Still, he is interested in the possibility of extending oil drains.
“I change my own oil right here every 10,000 miles. It costs me $75 every month. With this new truck maybe I’d be better off going to the new oil and doing a trend analysis to see if I can save a little money.” While Dunn is well protected given his particular engine and his application, the age of his DD might also be a factor to consider. At half a million miles a little added protection might be a good idea. Here, the safety margin Larkin mentions could help save costly repair bills and tows. But the deciding factor will probably be what Dunn discovers from a trend analysis.
On this point Larkin cautions, “If you want to extend drain intervals, you need to talk to your oil supplier and your engine manufacturer. They can tell you what to look for in your trend analysis.” All three major oil suppliers, Chevron Texaco, Exxon/Mobil and Shell, offer oil analysis programs complete with interpretations of results. However, it is to the benefit of the informed owner operator to understand the details so that he can talk knowledgeably with engine manufacturers and oil suppliers about his particular operation.
Despite interpretation available from the analyses of all three oil suppliers, some parameters can be confusing. Gary Parsons, Commercial Automotive Business Manager, Chevron Texaco Global Lubricants, cautions that one major category, total base number, TBN, can fool you. “Our analysis determines condemning limits,’ Parsons says. “If your TBN drops below two, down from 11, you need to change the oil if you’re running a Cat. However, some oils have a high TBN and still have high levels of acid.” To avoid such confusion, Parsons recommends working with oil supplier and engine manufacturer to optimize the use of test results. Parsons also suggests choosing the optimal level of testing. Chevron’s testing runs from $15 to $50. You can call 1 800 LUBETEK to set up testing.
Larkin suggests keeping close tabs on the relationship between viscosity and soot. Trend analysis must be done to find this relationship. “Look at your viscosity numbers to find out if they remain flat,” Larkin says. “If viscosity is going up at a higher rate than soot, your oil is thickening. On the other hand, if viscosity remains steady and soot numbers go down, your oil is dropping soot. Either way you have a problem. With 15W-40, more than 3 per cent soot is too much. What you want to see is flat viscosity and soot rates. Never go above 25 centastokes, which is the measure of viscosity. You’re better off if that number is less than 20.”
Larkin also suggests keeping an eye on alkalinity and acid. “If alkalinity drops quickly, your oil is getting too acid. Don’t go below the point where acid and base numbers cross,” he warns. If the TBN, total base number, drops below four or the TAN, total acid number, rises above four, it’s time to change oil.” Larkin cautions that iron levels can be affected by oil and alkalinity rates. “What you want to see is a flat rate for iron, too. When acid and alkalinity rates cross over, more iron will show up in oil.”
Conversely, elevated soot levels can be expected when iron appears in oil according to Bohofsky. In general, “Metals enter oil as a result of wear. But oil can handle soft metals up to two microns,” he says. “Elevated rates of soft metals like copper and lead indicate corrosion from acid or from water and coolant.” Catastrophic engine failure caused by coolant leaking through the liner is indicated by the presence of both potassium and sodium. However, the presence of sodium alone is not a real problem.
Catastrophic engine failures caused by large metal particles, what Larkin calls “shrapnel”, will not be picked up by analysis. “Shrapnel is too big for analysis to show. Owners are surprised with engine failures sometimes if they’ve been doing consistent analysis. But they shouldn’t be. Analysis will always show coolant leaks, overwhelmed air filters, dirt, fuel, soot, but large metal particles are undetectable.”
Sidebar
What is Extreme Service?
Oil suppliers formulate oil based upon a definition of extreme service. But how can the owner operator define extreme service for himself? It is an important question since drain intervals can be adjusted given operating conditions. Larkin, who wrote oil specs for Detroit Diesel, says the variety of applications makes formulating oil very difficult. “You can design an oil for the operation in the Mojave that is not going to work for the operation in Alaska where operators idle well over 50 per cent in extreme cold.”
It is likely your operation runs somewhere between these extremes. But where? To find out, take the following variables into consideration:
Per cent of idle – more than 30 per cent idle increases the severity of your operation as it affects oil. Per cent of fuel used at idle has a direct bearing on oil stress. 30 per cent idle elevates your service toward severe. Per cent of fuel at rated rpm and speed – if you are using more than 11 gallons of fuel per hour in mountainous terrain or 6 to7 gallons per hour in flat country, you are considered by many experts to be in severe service. Arcy remarks, “The more fuel consumed the harder the engine has to work.” Weight of typical haul – if you run heavy all the time, you are running in severe service. If you run in mountainous terrain, especially with heavy loads, you are running in severe service. If you run in dust and dirt, you are running in severe application. Larkin says, “If dust overwhelms air filters, you find it in the top of the combustion chamber where there is no oil. It wears out ring and liner interface all the more quickly because there is no oil present.” Ambient heat – while cooling systems keep your engine running at optimal temperatures most of the time, an incident of overheating causes oil degradation. Stop and go driving – peddle runs and ltl work qualify as severe service.
