My calendar shows that it is once again time to share the best (or at least the most interesting) letters and emails from the year. As always, there are compliments and criticisms. There are also some good thoughts about the industry and the problems facing us as businesses and as consumers. So here we go!
Russell Sas in Montana wrote in at the tail end of last year with a lengthy and well-reasoned discussion on oil consumption. He commented that auto makers have gone to thinner piston-ring packages and extremely low viscosity oil. He believed they had reached the mechanical limits of ring sealing. Some friction between the rings and cylinder wall is needed in order to minimize blow-by and maintain proper sealing in compression.
He related a 1980s-era story about problems with muscle cars with rebuilt engines having problems with oil consumption. When the rebuilders pulled the heads off, they noticed heavily glazed cylinder walls that prevented the rings from seating. Part of the problem was the assembly practice. The assembled rod/piston combo was dunked into a bucket of engine oil and then slid into the block, leaving the rings and cylinder wall heavily covered with lubricant.
Russ noted that this was with much thicker rings than what are being used today (0.043 inches). He thinks that a 0.063 inch ring package and oil no lighter than SAE 5W-20 might just solve the problem.
I have to say that this was quite a story, and my response was pretty detailed. Heres a synopsis:
I told Russ he was right that modern engine designers are primarily striving to improve fuel economy. In addition to the thinner rings and lighter oils, the tension on the rings has been significantly reduced. Im a lube guy and not a hardware guru, but his theory that blow-by has been increased by all of these improvements sounded reasonable.
As far as glazing on the cylinder bore or liner is concerned, some people have attributed that to friction modifiers. I thought that the heavy oil used in the bucket was probably drain oil which had a lot of bad actors in it due to the sludge and fuel contamination already present.
After I wrote in Januarys issue about selling my GMC pickup, Keith Barkley of Texas sent in a meditation on old trucks (and old folks): I can relate to your feelings with deciding to sell your faithful old 2001 truck. I have a 1999 GMC Yukon that I am going to have to part with soon for the same reasons as you had. It has served me well for 130,000+ miles. [It] fits my sitter just fine and it has a simple radio, not an entertainment center I cant operate. But time and miles have taken their toll. It is eye-opening to see what they are asking for a replacement for my old friend. Twice what my first house cost. So, at 85 do you put that much money under the car port to have ready for use a few times a month?
Not much you can say about that except thanks, Keith, for the kind words and the sentiment.
A frequent writer, Blaine Ballentine of Iowa, in February alerted me to Californias Assembly Bill 808, which addresses oil labeling. AB 808 has defined engine oils meeting only current (not obsolete) engine oil specifications as suitable for use on highway. The appropriate spec has to show on the label.
Blaine wrote: [The law says] internal combustion engines, which would include diesel, natural gas, sour gas, alcohol, stationary and racing engines. The API S specs in the Q&A section of the bill are completely inadequate for most of these engines. Racing engines are not covered by API specs; and there are no manufacturer specs, just the recommendations of the engine builder.
How do they determine if a product conforms? John Deere oil, for example, is not API certified, but I am pretty sure it meets John Deere requirements.
As it happened, many of us were just hearing about this new law, which took effect last January 1. I quickly surmised that SAE J304, which defines currently available automobile engine specs, was the probable source of the AB 808 definitions. Which it was, and still is.
AB 808 is still front and center, since it has spilled over into transmission fluids with some pretty significant consequences. There are many unanswered questions as well as some tricky traps and snares that oil marketers will have to navigate in order to continue to supply transmission fluids to the marketplace.
Bill Anderson in Maryland wrote to me in March asking when multi-viscosity oils were first used in motor vehicles. He recalls it was in the late 1950s, which is in line with SAEs first recognition of multi-viscosity oils in 1955 and their first official inclusion in SAE J300 in 1959. But were the oils in common use before they were officially recognized? Perhaps readers know the answer.
Mr. Armstrong Mwanza from Zambia wrote me a note asking about oil use on the African continent. He asked, What I am interested in most is how to generally know the type of oil to be used in both diesel and petrol engines in Africa, bearing in mind the climate change going on. Previously we knew SAE 30 was for petrol and SAE 40 for diesel. What about now? Secondly, how do I identify oil in terms of API Group I and II or III in relation to SAE, which is a common grading?
My response was that the climate and temperature ranges he faces on the African continent are not so different from those we face in North America. Our need for maximum fuel economy has resulted in lowering the viscosity of engine oils (especially as measured by high temperature, high shear rate viscosity) in order to reduce friction within the engine. Since I dont believe Africas vehicle marketers are being forced legislatively to reduce fuel consumption, I would continue to recommend SAE 30 for petrol fueled engines, but perhaps as an SAE 10W-30.
For diesel fueled engines, I believe that SAE 15W-40 is the best choice. Many studies here in North America have shown that SAE 15W-40 has lower oil consumption than straight SAE 40.
Base oil identity by Group I, II or III refers to the type of refining done. Group I base oils are refined using older technologies and are somewhat more difficult to upgrade with additives. Groups II and III are hydrogen refined creating a much cleaner oil. The important thing to remember is that additive chemistries and the companies that supply them are able to work with almost any base oil to provide a satisfactory finished engine oil.
The next subject is one that seems pretty scary to me. Ken Budinski from New York sent me a note on oil changes based on the oil life monitor. I bought a Chevy Colorado truck a year ago and had my first oil change at 3,000 miles. My second one came as a result of a change oil soon warning that stayed on my dash for a week before I could get an appointment to get an oil change. The dealer tried to talk me out of the change. He said that the sensor responds to run time and thermal history. The oil is still good and does not need to be changed until the sticker time, 2,000 miles hence. I asked them to change the oil now and give me a sample of the used oil and the new Dexos that they put in. They did so.
I work for a wear testing firm and I had ASTM G133 reciprocating wear tests run on a couple of hard steel versus gray cast iron with both oils. The bad oil produced twice the system wear as the same couple with the new oil. So the sensor was right, but I think that the dealer was wrong in telling me to ignore the sensor.
I responded by telling Ken that the oil sensor is a good indicator of useful oil life, that it was developed by some very good engineers (the late Shirley Schwartz of GM and her colleague Don Smolenski, now with Evonik), and that the dealer was in error to recommend going an additional 2,000 miles before changing.
As far as the wear test results are concerned, I hope to get more information and will update readers when I do. For now, the question is open: Was it the Dexos, or was it something related to the engine?
Al Frediani in Massachusetts mentioned to me in an email that he still has 12 quarts of Pennzoil Performax 100 sitting in his garage, which he bought over 20 years ago to put in his vintage Corvette. He wondered whether the oil was a true synthetic, as the bottle claimed, or if it was perhaps based on API Group III stock.
While Im pretty sure that the Performax is a true synthetic (at the time these were based on PAO and esters), I was more concerned about Al putting such an old oil in this vehicle. I advised him to check that the additives hadnt fallen out of solution over the years. If so, a newer oil would work just fine.
So heres to 2017. May it be interesting and educational, and please keep reading LubesnGreases!
Industry consultant Steve Swedberg has over 40 years experience in lubricants, most notably with Pennzoil and Chevron Oronite. He is a longtime member of the American Chemical Society and SAE International, where he was chairman of Technical Committee 1 on automotive engine oils. He can be reached at steveswedberg@cox.net.