Synthetic Oil 001 OR Just a Search for the Facts PREAMBLE This current CaptnWil "Work in Progress" really began about nine months ago with an axle disaster and became full blown when he began a search for a new boat. This "Work in Progress" is about, "What is the real story about synthetic oil?" This epistle will be a collection of some information that was new to, or forgotten by, CaptnWil and may be of interest to you. Then again, it may be of absolutely no interest to you and you should hit the delete button. CaptnWil did this same type of investigation years ago when API CD oil first came out. In those days, the research had to be done in university libraries, etc. and was much harder that today when searches on the Internet are so easy. An equipment supplier in the repair of the axle disaster insisted that synthetic gear oil be used in the differential of my truck. The immediate reduction in noise made an impression on me that I have not been able to shake. Then the announcement that Cummins now meets the IMO Emissions Compliance For Marine Engines, and the observation that Yanmar has discontinued one series of diesel engines and replaced that series with another to meet emission requirements, got the search going full speed. There are things that you and I need to know that relate to diesel engines in general, and engine oil in particular. It is important to remember that we can't change any of these things; we must just react to them. Almost always, the search leads to a much longer journey than expected and this search is no exception. If you think this report rambles, well the search itself has rambled. Somewhere down the line, it is hoped that the picture will become clear, or at least clearer. What follows is an attempt to simplify the mass of data that is available on the listed subjects. It is intended to give you a feel for the issues and is not intended to make you an expert of these subjects. In addition, it is based on four-cycle diesel engines. This information may or may not be appropriate for two-cycle diesel engines. WHERE THE OIL SPECIFICATIONS COME FROM All that follows relates to the USA. In these latter days, the government issues some emission requirement for engines -- diesel engines in this report. Then the major engine manufacturers (Caterpillar, Cummins, Detroit, Mack, etc.) determine just what is required to make the engine meet those requirements and what new requirements are necessary from the engine oil with this new engine specification. Then, together with the Society of Automotive Engineers (SAE) and American Petroleum Institute (API), a new oil specification is generated. After that, the oil companies meet or try to meet the new requirements. Any engine oil posting the new oil designation in the API format qualifies to meet the warranty requirement of engine manufacturers requiring that specification. That is to say that if an engine manufacturer requires SAE 15W-40 oil meeting the CH-4 specification, any brand oil of any kind (synthetic or petroleum based) with such a proper API label will qualify to satisfy the engine manufacturer's warranty requirements. The engine manufacturers cannot require a particular oil by brand and model unless they pay for the oil for the life of the engine. WHY THE OIL SPECS CHANGE SO OFTEN Until the government (EPA) got into the act, oil specifications remained stable for a very long time. Before the '90s, diesel oil came in two flavors, CC and CD. CC was for un-turbocharged engines and CD was for turbocharged engines. Those were the days of black smoke from most every diesel engine you ever saw. Since those days, the EPA has enforced more and more rules to reduce "Air Pollution" from diesel engines. It is almost a law that everything done to reduce air pollution in diesel engines puts those pollutants into the engine oil. Handling the increased pollutants puts new requirements on the engine oil and the engine manufacturers respond with increased requirements for the oil, and in cooperation with SAE and API, a new engine oil specification is born. We're up to CH-4 done in 1998. IMMEDIATE CONCERNS The EPA and the major engine manufacturers have agreed to meet the emission requirements of 2004 in 2002 instead of 2004 - that's the reasons for the announcements from Cummins and Yanmar. I have been advised that the only practical way to meet these new requirements is to retard the injection timing and provide EGR (Exhaust Gas Recirculation). That, dear friends, is a serious problem. In addition to increased stress on the oil, fuel economy will suffer. The days of the simple diesel engine are all but gone! This all means that a new oil specification is on the way. It currently has the name (PC-9) and is scheduled to become effective in October 2002. WHAT DOES THIS HAVE TO DO WITH SYNTHETIC OIL Only the naive would believe that the EPA will be finished with their diesel engine involvement with the 2002 agreement. The engine manufacturers and oil companies are certainly not naive and are looking to the future. Every premium brand of diesel - synthetic and petroleum based - oil that I know about has met the 1998 CH-4 requirement, but that does not speak to the future. It seems that in anticipation of future requirements, both the oil companies and engine manufacturers are edging toward the synthetic product. While not requiring synthetic motor oil, the major diesel engine manufacturers are selling synthetic or synthetic blend oil under their own name or directly from the oil manufacturer. Cummins is selling a synthetic blend from Valvoline. Caterpillar and Detroit are selling Mobil Delvac 1 under their own brand names. It is CaptnWil's opinion that these moves are in anticipation of the time when oil specifications will exceed what is possible with natural petroleum based oils. AMSOIL and Mobil have had full synthetic oils for some time, but almost all oil companies are now selling either full synthetic or synthetic-blend oils for diesel engines. It is significant to CaptnWil that Shell has just joined the club with their synthetic-blend, Rotella SB. It is significant because of their long and successful run of Rotella T being the most popular heavy-duty diesel motor oil in the country. Something has to be going on if they offer a competing product for this most popular oil. WHAT THE NUMBERS MEAN It is common knowledge that oil designated as SAE 15W-40 is multi-viscosity grade oil and oil designated as 40 is a single-viscosity grade oil. Both of these expressions are a code that tries to describe the viscosity nature of the oil that is of importance to the engine user. The numbers and letter have been arbitrarily chosen to relate viscosity characteristics to oil viscosities at one or more temperatures - they are not viscosities themselves. Sometimes the number is referred to as weight, as 40-weight oil. All 40-weight oils will fall into the same viscosity specifications at 100 C. The larger the number, the greater the viscosity (thicker) the oil is at 100 C. When the number stands alone (40), it relates to the viscosity of the oil at 100 C (212 F). That temperature is close to the normal operating temperature of most diesel engines. Many diesel engines require SAE 40-weight oil at operating temperature. This operating weight has to do with the shear stress the oil film is under during normal engine operation. Many gasoline engines require SAE 30-weight oil since their oil is under less shear stress than diesel engines. The lower the number, the less work it takes to pump the oil and the greater the fuel economy. When the number is combined with the letter W (15W), it relates to the viscosity at two very low temperatures. These temperatures are not the operating temperatures of the engines, but are related to how hard it is to crank an engine and how hard it is to pump the oil. If oil is rated at 15W it must allow normal cranking of an engine at -15 degrees C and not cause oil pump pumping problems at -25 degrees C. It should follow then that oil designated as SAE 15W-40 will act like SAE 40-weight oil at 100 degrees C and SAE 15W oil at -15 degrees C for cranking and -25 degrees C for pumping. Note that this is not 15-weight oil, but 15W-weight oil. As a case in point, SAE 20 oil has the same viscosity requirements at 100 C as does SAE 20W oil, but the plain SAE 20 oil does not have a cold cranking and cold pumping requirement as SAE 20W oil does. None of these specifications speak to any other temperatures, but different oils show different characteristics at temperatures between the extremes. We'll be investigating that issue a little later. SYNTHETIC OIL AND TODAY'S ENGINES Some of the reasons for investigating synthetic motor oil for future engines have been presented, but a great many of the engines in our marine world today were born long before these new concerns began to appear, and only a few engines that will be purchased currently will put the stresses on the oil as described above. So what about the present engines and synthetic motor oil? The exceptional service of premium petroleum based oils in diesel service is well established. Astonishing results like Charlie Sims' documentation of a Detroit two-cycle engine going over 1,000,000 miles with two oil changes with no measurable engine wear when Shell Rotella T was combined with a Gulf Coast Filter bypass oil filter is testimony to the fact that if kept clean, good petroleum-based oil does not wear out and provides unlimited service life. Not only is there much evidence of the excellent service of today's premium from the literature, but my own Cummins 6BTA5.9 went over 20,000 miles with Shell Rotella T and a GCF bypass oil filter without even a filter change. Portable Oil Analyzer tests were made on the oil every few hundred miles. After 20,000 miles, the oil was almost like new. That is testimony to all three components, the bypass filter, the oil, and the engine. Be warned not to jump ahead and try to extend oil drain periods without careful laboratory testing results. There is no question that the premium diesel motor oils of today do a marvelous job and meet every requirement of the newest API CH-4 specification. That should be enough, shouldn't it? Well the oil companies who sell synthetic motor oils say NO! You would expect that from a company who sells synthetic or synthetic blends only like AMSOIL, but here are a couple of examples from companies who sell both synthetic and petroleum based oil. Here's an example from Shell. On Rotella T: "Rotella T Multigrade SAE 15W-40 with Advanced Soot Control is Shell's primary recommendation for heavy-duty diesel and mixed fleets in all types of over-the-road service. It is also recommended for off-highway applications where all-season universal engine oil is desired, such as construction, mining, logging and agricultural services." Then on Rotella SB "Rotella SB contains synthetic base oil components to impart special performance qualities critical for both on-highway and off-highway service applications, especially where all-season use and enhanced fuel economy performance is desired. They are highly recommended for extended cold climate operation. "Application ... "New advanced design low emission diesel engines (as well as older engines) from Caterpillar, Cummins, Detroit Diesel, Navistar, Mack, Volvo. ... "Features/Benefits ... "Extended oil drain capability "Fuel economy - reduced fuel consumption when compared with conventional SAE 15W-40 oils in laboratory diesels. SAE 10W-40 oils show a 1% improvement in fuel economy..." Since Mobil supplies motor oil to both Caterpillar and Detroit Diesel, some of their comments about their synthetic Delvac 1 are interesting. ... "1. Increased fuel economy averages 3 percent or more. In Caterpillar 3176B field tests, Delvac 1 achieved 5.7 percent more miles per gallon than conventional 15W-40 oil (7.39 vs. 6.99 mpg). In Detroit Diesel Series 60 field test, mpg with Delvac 1 was 4.7 percent greater (6.41 vs. 6.12 mpg). "2. Extended vehicle service results from oil drain intervals of at least 60,000 miles... "2. Better corrosion protection, reduced engine component wear and fewer piston deposits help extend engine service life..." In addition, in some very controlled situations, Mobil will give fleet owners a guarantee about increased fuel economy when using Delvac 1. All of these statements were made in advertising material and should be considered in that light, but they do put the companies in jeopardy if those statements are proven to be false or misleading. It seems to be the general conclusion from the literature that synthetic motor oil is superior to petroleum based motor oil. There seems to be some dispute between the suppliers whether full synthetic or a synthetic blend is better. The major issue seems to be whether the increased cost of the synthetic oil is worth its benefit. It is encouraging to CaptnWil that Cummins advised that there would be absolutely no problem by changing from one type of oil to another as often desired. That gave CaptnWil the green light of do some investigation on his own. Something like throwing a well-known rabbit into the briar patch, don't you think? HOW ABOUT THE COST The following were prices on or about April 1, 2000. With the rapidly changing oil prices these days, they may not be correct when you read this. At WalMart, a six-gallon case of Shell Rotella T had a price of $34.76 ($5.79/gal). At a Cummins Distributor, Premium Blue 2000 synthetic blend was $11.36/gal. At a Mobil Distributor, a four-gallon case of Delvac 1 full synthetic was $86.22 ($21.56/gal) At a Caterpillar distributor, Caterpillar's relabled Delvac 1 was $20.22/gal At an AMSOIL Dealer, AMSOIL 15W-40 was $4.53/qt (18.12/gal). If we use the Shell Rotella T as a base, the synthetic blend costs 1.96 times more, and the most expensive pure synthetic costs 3.73 times more. In addition, the most expensive pure synthetic cost 1.9 times more than the synthetic blend. PURE OIL COST CONSIDERATIONS For this exercise, make these assumptions: 3% increase fuel savings for pure synthetic oil Fuel consumption of 4 gallons per hour. Diesel fuel price $1.50/gal Normal oil drain interval of 200 hours and no oil added between oil changes. Full-Flow oil filter price $8.00. Oil capacity of four gallons. Except for the no oil added assumption, this is a pretty normal 40 ft.+/- recreational trawler situation. In the following equations, * is the multiplication operator. The base oil cost per change using Rotella T would be 5.79 * 4 + 8.00 = $31.16 for 200 hours of operation. The oil and filter cost for the most expensive synthetic would be 21.56 * 4 + 8.00 = $94.24. The fuel savings would be 0.03 * 4 * 200 = 24 gallons, and the cost savings would be 24 * 1.50 = $36.00. To have the same cost as the Shell Rotella T, the oil drain interval must be increased (94.24 - 36) / 31.16 = 1.87 times or to 1.87 * 200 = 368 hours. With these assumptions, the synthetic oil would cost less if the drain interval could be extended to more than 368 hours. Now lets run the numbers if the engine requires one quart of oil every 20 hours. Total oil for Shell Rotella T. 200 hour drain = 200/20/4 + 4 = 6.25 gallons. Now the total cost is 6.25 * 5.79 + 8.00 = $44.19 If the engine used one quart every 20 hours, the synthetic oil would cost 6.25 * 21.56 + 8.00 = $142.75 minus the $36.00 in fuel savings for a total cost of $106.75 for the first 200 hours and 200/20/4 * 21.56 = $53.90 - $36.00 in fuel savings = $17.90 for a net oil cost for each additional 200 hours until oil drain. It is obvious that both extended oil drain interval and increased fuel economy is necessary to justify synthetic motor oil for a diesel engine on an oil cost basis only. It should be fairly easy to run these same kinds of numbers for your own boat. There is a statement from Mobil about Delvac 1 reduced oil consumption that was not considered in these calculations, and I don't feel comfortable in considering, except the part about mechanical condition. It is passed on as a note of interest only. "The synthesized base stock in Delvac 1 is much more stable and consistent versus conventional base stock that have a broader mix of petroleum components. The combination of resistance to oxidation and reduced evaporation at high temperatures, as well as consistency of synthetic base stock, results in less oil being consumed. Be aware, however, that if your engine burns oil today due to a mechanical condition, Mobil Delvac 1 will also probably experience high oil consumption. There is no substitute for fixing mechanical problems." If you run these same kinds of numbers using a GCF bypass oil filter which extends both the filter change interval and oil change interval, the numbers favor the synthetic oil even more because of the longer oil drain periods. The bottom line is that the longer the oil drain interval, and the less the oil consumption during normal use, the better the economy of the synthetic oil becomes. You should have noticed that the estimates shown above do not include any labor cost. Most of us change our own oil, but adding any labor cost to the numbers would tend to favor the synthetic oil with longer oil drains. Remember the standard warning. If you extend the oil drain interval with any oil for any reason, do so only with the guidance of a good laboratory analysis program. The lesson is: The oil will tell you if you let it! BUT WHAT ABOUT QUALITY There are no easy numbers to run on this subject. The only real way to know for sure is to run two engines under exactly the same conditions until failure and compare the two. Doing that is well beyond the capability of most of us, and the results would be so long in coming that we wouldn't care about them after we got them. But remember one of CaptnWil's laws. If you can't solve one problem, solve another. In this case, we can let the oil tell us the story if we monitor each type of oil in the same engine with good laboratory analysis, we can get a handle on the differences, if any, in the oil quality. Our major problem in doing this is that we can't duplicate the conditions in each test because we are operating in the field and not in a laboratory. In addition, we must have patience to see the test through to a finish. Careful study of laboratory oil analysis reports over a 500-hour period should give a pretty good indication of what each oil type is doing. To make a comparison of just two oil types in this fashion requires a total of 1,000 hours of running time. How many years is that on your boat? An alternative is to follow CaptnWil's Work In Progress on this issue. The test is halfway done because there are already 20,000 miles (500 hours at 40 mph) of records on SAE 15W-40 Rotella T. There are about 20 hours of records on Valvoline Premium Blue 2000 synthetic blend. But here is the real kicker. The test now begins on the full synthetic Delvac 1. Emotion overcame logic, and said, blow a hundred bucks, and get right to the heart of the matter with full synthetic oil. After all, 20,000 miles takes a long time, and CaptnWil wants the answer sooner than that. CaptnWil's reason can be called into question often, but less than two nights dockage fee seemed a small price to pay for an answer to this question. STAY TUNED That's enough for now. CaptnWil must leave to go look at a boat - can't stand this boatless condition. You'll get first impressions on the oil test when CaptnWil returns next week. CaptnWil, Ret 40 Pier Pointe New Bern NC 28562 (252) 636-3601 captnwil@coastalnet.com