PCMO vs HDEO detergents

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FrankN4

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I may be reaching that point where I am becoming educated beyond my intelligence. confused A diesel oil will have an overbased detergent package because of the various acids that can result as a by-product of combustion and fuel additives. Newer diesel engines have particulate filters, and require low SA oils. I am having trouble determining how you accomplish both. Looking at UOA, VOA, and PDS, I see many diesel oils still have calcium in the 3000 ppm range. shocked Can someone explain to me, in close to english, how you keep the ash down and the base up? Is there another secret additive, a new formulation as in the new ZDDP packages, or whatever? What would be the advantage of an overbased oil in a gasoline engine. Would it be needed in an E-85 engine? Especially since most PCMO oils have a ZDDP pack of around 800 or so. shrug
 
I'm pretty sure the low SA diesel oils are for engines that burn very cleanly. I'm sure a traditional diesel oil could help in an E-85 engine, though.
 
Well, what about using some other cations instead of Calcium? Like quaternary ammonia or similar chemistry?
 
Originally Posted By: Pablo
Nik is close. They use some Ca compounds, but they also use stable amines.
When I think of the word "amines" I think, ammonia, organic, and base. So, and I am asking, could you keep the calcium at Xppm and increase the base by adding/increasing, better utilizing the amines? I always thought 3000 ppm was "high" for calcium. Is that incorrect? I noticed Valvoline dropped calcium from 25xx ppm to 1910 ppm, and added 490 ppm sodium. SA went way down but so did the base number of the oil, it really went down. Can you have a low TBN, yet still have something, like amines, that kept that TBN effective/working longer, or, is TBN, TBN? I asked a chemists, not a tribologist, about calcium and phosphorus. He said if there was a lot of calcium, it would compete with phosphorus for surface area. He said an oil for a race engine may have little or no calcium and really high phosphorus. I am guessing that would be an extremely low base oil? shrug
 
Isnt it something like too many of one additive over powers or takes surface room of another while too much in general reduces base oil and its properties in the engine ?
 
Originally Posted By: FrankN4
Originally Posted By: Pablo
Nik is close. They use some Ca compounds, but they also use stable amines.
When I think of the word "amines" I think, ammonia, organic, and base. So, and I am asking, could you keep the calcium at Xppm and increase the base by adding/increasing, better utilizing the amines? I always thought 3000 ppm was "high" for calcium. Is that incorrect? I noticed Valvoline dropped calcium from 25xx ppm to 1910 ppm, and added 490 ppm sodium. SA went way down but so did the base number of the oil, it really went down. Can you have a low TBN, yet still have something, like amines, that kept that TBN effective/working longer, or, is TBN, TBN? I asked a chemists, not a tribologist, about calcium and phosphorus. He said if there was a lot of calcium, it would compete with phosphorus for surface area. He said an oil for a race engine may have little or no calcium and really high phosphorus. I am guessing that would be an extremely low base oil? shrug
Yes, its possible to have two different rates of TBN depletion with two different oils run under identical conditions. Yes, that is part of the reason pure race oil don't have a whole lot of TBN. Generally the oil only gets one run and sometimes so does the engine.
 
They use Urea NIK in the particulate filter to do what your Ammonia would do but it is being used in the particulate filter. Ammonia would not go over well in a crankcase. THe stable amines are the way to go you just have to watch out for seal damage as even stable amines can do a number to old seal maeterials.....Things like teflon would not be affected ever by amines. We used to add a product from Schaffers that had a heavy load of AMines and Crysilic Acid to crankcase oil to clean and protect it could also be added to the fuel. It was Nutra 131. Their used to be a product when I was a kid that you added to your fuel oil furnace to keep it clean it was basicly Crysilic acid it would remove soot and carbon through the combustion process and keep everything clean! I cannot recall what it was called "Clean Sweep or Keep it CLean " something like that??????
 
somewhat related; in a given engine, will an oil with higher TBN have longer life than an oil with lower TBN? all else being equal
 
Originally Posted By: Hoosier_Daddy
somewhat related; in a given engine, will an oil with higher TBN have longer life than an oil with lower TBN? all else being equal
Ah, the old "all else being equal" trick. I think you could have a really high TBN, deplete most of the add pack, and still have a "good TBN number" left. Your oil has turned to a lapping compound but it still neutralizes acids. TBN does not tell you the condition of the anti wear agents, the FM, viscosity shear of VII, viscosity shear or thickening of the base oil, it doesn't tell you the condition of the anti foam agents, anti rust agents, antioxidants(most of them), and on. There is much more to an oil than the base number. I am seeing PDS, VOA of oils with TBN in the 7-8.5 range. One of the finest European spec oils has a TBN of 8. I believe, my personal opinion, ONE of the reasons Amsoil 5W-40 European and Valvoline Synpower give such stellar results is because of their TBN to anti wear ratio.
 
Originally Posted By: Hoosier_Daddy
are detergents depleted over time or do they still show up on UOA but no longer function as they did?
Yes they are BUT unless they fall out as sludge they will still show on a UOA. SAP is the sum of all the metals and P in the oil. using a high over base CA or MG for instance will raise TBN but allow a lower total SAP, that and other additves such as Aminic AO which will also help raise TBN new dispersants also. bruce
 
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