Group I better than Group IV??

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Ok, now before you get too excited and roll out the troll icon, let me qualify a bit. I'm talking about VARNISH potential only. A while back there was a post which said Castrol Syntec was removing top end varnish. This drew my skeptical response among some others as a group IV oil had been previously used. See this thread: http://theoildrop.server101.com/forums/s...part=1&vc=1 More recently I've become aware of a varnish problem we are having with one of the turbines in our fleet, and have done a bit more research into it, with some very interesting findings: 1. This is a fairly recent problem in the industry and by some accounts reaching "epidemic" proportions. The prime cause is very surprising - better quality base oils. Turbine oils have switched from Group I to Group II over the past 10-15 years or so, and problems are now showing up that have not been seen before. More on that later. 2. The other issue is that additives for these newer more advanced base oils have to be carefully selected or they can result in severe varnish problems. Other more minor findings are that varnish tends to form on cooler surfaces because solubility of varnish in oil reduces with temperature (contrary to what I thought). Appliations where there is start-up and cool down cycles are more susceptible to varnish (like autos). The basic problem with the base oils was one I raised in the Group III vs IV discussion and that of reduced solubility of the higher group oils. Not only is it harder to dissolve additives, it is also harder to keep sludge such as varnish in suspension, with this reduced solvency. One specification for base oils that is not so common but important is the aniline point. It is a measue of the solvency of the oil, with a lower number meaning higher solvency. See this graphic for a comparison of the aniline number by base oil group. The second table is irrelevant for this discussion. As you can see that Group I is the best. This stands to reason as one of the distinguishing charateristics of the higher base oils is lower aromatic content, and resulting higher flash point. These aromatics however are probably responsible for the higher solubility of the oil. So long story, but I can now understand and believe that switching from a Group IV synthetic to a lower base oil group or one with better additives can dissolve varnish as was reported in the thread above. There are a number of cases of this happening when methods are implemented to remove varnish from turbine oils. Under the right conditions varnish can be redissolved. I'm not so sure however, that other than cosmetic coloring, varnish is a real big problem in auto engines? Perhaps it may plug oil filters sooner especially fine ones, or constrict small oil flow orifices, especially ones in cooler areas of the engine. So two questions, with the second one being somewhat off topic: 1. Should we periodically go out and find a group I based oil and keep it in for an oil change to clean out the varnish we may be accumulating by using the "high quality" synthetic oils? If so, what group I oil may be the best quality, given the other problems with group I? Doing this in summer would seem to be one of the obvious safeguards. 2. This one is If you had a turbine with severe varnish problems how would you select a good replacement oil? Will manufacturers actually tell you what base oil they use? Or do you just pick one with the lowest possible viscosity index? Are there specific additives that are good and bad with respect to varnish in Group I or II? Bruce, I think you and others may have experience here. There are many articles on the net re varnish in turbine oils if you look. Here is one. http://www.practicingoilanalysis.com/article_detail.asp?articleid=428&relatedbookgroup=PowerGen
 
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Now, now, don't everyone go jumping on Ron. He did not state a fact, he asked a question. I think I know what the answer is, but since I'm not a chemist or experienced blender I also would be interested to here what the EXPERTS on this site have to say. So I hope Bruce, Mola, Terry, or anyone else with credentials jumps in.
 
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Myself J/K ... I would also be interested, all the knowledge here you can't get from you stealer (OOP's Dealer) machanic. With the contributions here I learned alot. Correction STILL LEARNING..
 
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As far as bashing Ron. I'd have to say this is one of his best posts so far. The title is slightly misleading but the topic is worthy of bitog. I await expert responses. As far as responses I will ignore see thermactor's reply above
Quote:
NOW YOU'VE DONE IT!
great reply all caps too!
 
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I spoke with an engineer about varnish and he said it was absolutely no problem at all. Varnish isn't an issue. Group I's are inferior oils all things considered. This is why they are no longer used. Group II+ and III's are the majority base oils now used.
 

JHZR2

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I recall hearing from a mobil engineer a few years back that they formulate Delvac 1300S with some group I oil in it because of its added cleaning capability... JMH
 
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If this is Ron's "best" post then - "yikes" I appreciate Ron's spirit, it's his "agenda" and perhaps his critical thinking skills that trouble me (him?). he is on to something and that is "like basically dissolves like". And as we have seen in Schaeffer's products (blends) the addition of several groups makes a good oil. However to say (ok question) "Group I better than Group IV??" is a bit misleading. Let's take this:
Quote:
One specification for base oils that is not so common but important is the aniline point. It is a measue of the solvency of the oil, with a lower number meaning higher solvency.
Aniline point is simply not so important in a well formulated motor oil. The difference shown (about 19°C) is irrelevant in usage. The meat of logic error is based on this and your definition of aniline point: From noria:
Quote:
The minimum temperature for complete miscibility of equal volumes of aniline and the sample under test ASTM Method D611. A product of high aniline point will be low in aromatics and naphthenes and, therefore, high in paraffins. Aniline point is often specified for spray oils, cleaning solvents, and thinners, where effectiveness depends upon aromatic content. In conjunction with API gravity, the aniline point may be used to calculate the net heat of combustion for aviation fuels.
and from a random google (Alken-Murray):
Quote:
The aniline point of a petroleum product is the minimum equilibrium solution temperature with an equal volume of freshly distilled aniline.
I have to get ready for work, but to cut to the chase - it's a leap to say that this leads to deadly varnish. It's true that group IV (and group V) oils contain less aromatic molecules (hence the bit higher aniline points) - this does not mean they are varnish formers. Also, again this slightly higher aniline point may require more careful additive selection during formulation, this was long ago overcome. I don't disagree that certain low aniline point solvents and oils will clean some crud, but this does not lead to the conclusion in your title. This is because one needs to look at the whole formulation not just one lesser aspect of an oil. The lower aniline point does not trump the other good properties of a PAO.
 
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Ron, I worked as an oil change tech and assistant manager years ago. Forgive me if I lack specifics here, I did not take the original call (a good friend did that I shall use this post as an excuse to reconnect with did). But anyhoo... One day, we (Mike the manager, and myself) received a call at the shop from somebody that was the owner of a small manufacturing firm. I have no idea what is was, or what kind of machines we were talking about, since I didn't take the call, and I presume the gentleman was in a rush frantically calling as many oil change facilities, oil reps, retails stores, and the like in the desperate search for the original formula of Mobil1. The reason, the then newly reformulated Mobil1 "Tri-synthetic" formula no longer lubricated the machinery as well. Again, sorry if I lack specifics, but for some reason the newer Mobil1 was less effective than the old pure Group IV base in this albeit unintended side application. Actually, I was a able, through my friend who called him back, to guide him to a Thruway (Rte. 90) service area with a Mobil gas station, in which I had recalled seeing dozens of bottles of not only the old formulation Mobil1, but M1 in the original plactic bottle design! I'll see if I can dig up any information on this...
 
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Varnish can become an issue in industrial machinery and turbines because it causes sticke valves and controls. My understanding is that the primary cause of it in industrial applications is the inadvertant mixing of non compatible oils or switching groups. Also contamination from moisture is a contributor. In autos varnish is mostly a cosmetic issue(for most varnish cases ar mild and restricted to non moving parts) but in severe cases can reduce flow or block/stick pressure check valves in complex piston oiler systems.
 

JAG

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Group 5 oils have strong stability, high VI, low volatility, and the ability to dissolve carbonaceous materials like varnish. Group 1 only has the latter. Of course not all Group 5 oils are the same in this regard. If one wants to dissolve these things, the best way is to use any good motor oil and Auto-RX.
 
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First off: Turbines run on Grp II oils? Is this correct? I thought turbine applications required Grp IV or V anyway. From what I have read, there are no pure Grp IV oils. They all require something else for the solvency of additives. This usually comes in form of esters @ ~%20. These esters should provide at least good cleaning properties, and are more than likely better at cleaning than a Grp I. Especially since the PAO is much less likely to form varnish than the Grp I, which would exacerbate the original problem.
 
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Quote:
If one wants to dissolve these things, the best way is to use any good motor oil and Auto-RX.
Beat me to it JAG. As far as formulated oil, Esters, Alkylated Naphthalenes, etc, along with additives are used to address solubility issues with certain basestocks. I'm guessing Ron will be looking for a Group I, Group III blend as his "favorite" oil.
 
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This market is too cheap to try synthetics in turbines, although I have some very happy customers with them in Compressors. All of my customers for turbine oils are on group II, and none have ever commented on varnish. I would think that a properly formulated synthetic will normally be a combination of IV and V that will have the right solvency for the equipment.
 
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