10W vs 10W-30 vs SAE 30 cylinder wear
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That's sort of what I was thinking. Maybe I missed a lot of the details of the test, but I'm wondering how using a number of oils far thinner than recommended tells us anything about VI improvers...
I don't understand how you cannot tell what it may tell us about viscosity index improvers. The 10W-30 has them. The straight 30 wt. does not.
And the 10 weight doesn't likely have any VII either but still shows almost across the board worse wear numbers than the 10W-30. It's especially interesting though that the 10 weight is worse at colder temps yet better at slightly higher ones until the curve climbs at still higher temps and its wear increases.
I suppose my overall point is this. I'd be hesitant to use this test as an illustration of anything in particular given we don't have a clue what oils were used. From the limited data one could also draw the conclusion that "generally thicker oils are better" or that "lighter oils don't give us less wear at low temperatures" and have those conclusions be as confident as "higher levels of VII cause more wear."
By the way, I'm not arguing that point, all other things being equal. But this test doesn't do much to prove it to me either way. It also doesn't tell me if this is typical of engines in general or unique to this one because of something simple like excessive fuel dilution. For another other reason, it seems quite possible that too light a lubricant may have been used in the first place and that the straight 30 weight was simply closer to optimum for this engine than any of the others.
And, as we've seen more than a few times before, the results seen from fully formulated oils tend to defy our simple finger pointing at any one characteristic as the explanation for certain limited test results...
So am I doubtful enough with good cause or just doubtful?
I suppose my overall point is this. I'd be hesitant to use this test as an illustration of anything in particular given we don't have a clue what oils were used. From the limited data one could also draw the conclusion that "generally thicker oils are better" or that "lighter oils don't give us less wear at low temperatures" and have those conclusions be as confident as "higher levels of VII cause more wear."
By the way, I'm not arguing that point, all other things being equal. But this test doesn't do much to prove it to me either way. It also doesn't tell me if this is typical of engines in general or unique to this one because of something simple like excessive fuel dilution. For another other reason, it seems quite possible that too light a lubricant may have been used in the first place and that the straight 30 weight was simply closer to optimum for this engine than any of the others.
And, as we've seen more than a few times before, the results seen from fully formulated oils tend to defy our simple finger pointing at any one characteristic as the explanation for certain limited test results...
So am I doubtful enough with good cause or just doubtful?
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Wow!
Who would have thought that an SAE 30 might outperform a multi-grade oil, at least under a very specific set of conditions.
The owner's manuals for both my '81 Vanagon and '88 190E 2.3 listed SAE 30 as among the recommeded oils for any temperature above freezing. I did use a 30 in the VW during the summer. Maybe the old MB would have been happier with a shear-proof 30 than the 20W-50 I gave it for the summers. If I happen upon another nice old MB, I will have to give straight 30 a try for warmer weather seasons.
Who would have thought that an SAE 30 might outperform a multi-grade oil, at least under a very specific set of conditions.
The owner's manuals for both my '81 Vanagon and '88 190E 2.3 listed SAE 30 as among the recommeded oils for any temperature above freezing. I did use a 30 in the VW during the summer. Maybe the old MB would have been happier with a shear-proof 30 than the 20W-50 I gave it for the summers. If I happen upon another nice old MB, I will have to give straight 30 a try for warmer weather seasons.
jsharp, good points. My first post in this thread said in response to the data: "Neat..." and the reasons for that are similar to those you've said. I didn't feel comfortable drawing hard conclusions from this data by itself. What's neat is that other studies on the effects of polymers on lubrication are consistent with the the wear data for the 10W-30 and straight 30 wt in this graph on the higher temp range. A lot of research is going on currently to investigate the true viscosity of oils as a function of shear rate and pressure. See Terry's semi-recent thread in the Interesting Articles section if you want to find a recent one. Tribology and Lubrication Technology was nice enough to mail me the magazine with that article in it for free.
I currently can't even begin explain the differences in wear between the 3 oils in this graph at the lower end of the temp range.
I hope the links I posted in this thread helped shed some light on this subject for everyone.
I currently can't even begin explain the differences in wear between the 3 oils in this graph at the lower end of the temp range.
I hope the links I posted in this thread helped shed some light on this subject for everyone.
...But not necessarily a real world daily driver situation in a modern engine...
LOL This reminds me of that "dirty oil lubricates better than clean oil" (or whatever) thread...
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LOL This reminds me of that "dirty oil lubricates better than clean oil" (or whatever) thread...
Yeah . . . clean oil is bad for your engine . . .
The gensets that I'm experienced with are under full load within 10 seconds of starting. THAT is why the oil is warmed. It is because the engine is kept pre-heated there is no need or desire to run multi-weight, they do not heat the engine because they desire to run single weight.
When discussing the "cold" performance on the original graph on page 1, we need to keep in mind that the temperature scale is in celcius. Therefore the "cold" data in the graph is essentially room temperature.
I'm tempted to try ACD or ATM in my car to see if it lowers the 1/2qt of oil I add every 5k miles. I've often wondered if VII's can contribute to oil consumption. I would think though that Noack volatility would be a better indication of oil consumption.
This may very well explain my very low wear metals with SAE 30 in my Volvo.
I have always said that the more actual oil in a formulation the better it can lubricate and in situations where you don't need vii's (pour point agents and thickeners) - why use an oil with them??
A marketing way to say this would be along the lines of "Allow the properties of synthetic oil to shine - don't muck them up with thinners or thickeners that don't actually lubricate"
I have always said that the more actual oil in a formulation the better it can lubricate and in situations where you don't need vii's (pour point agents and thickeners) - why use an oil with them??
A marketing way to say this would be along the lines of "Allow the properties of synthetic oil to shine - don't muck them up with thinners or thickeners that don't actually lubricate"
Whew!! That was a lot to digest.
So, to sum up a little:
Little or no VII's with a great base oil with modest VI and a good additive package containing the minimum amount of PPD's and not necessarily having to be a multigrade lubricant might turn out to be the best for certain areas of protection...
Now that does sound logical, but what about all of the other amounts of wear on the other components?
So, to sum up a little:
Little or no VII's with a great base oil with modest VI and a good additive package containing the minimum amount of PPD's and not necessarily having to be a multigrade lubricant might turn out to be the best for certain areas of protection...
Now that does sound logical, but what about all of the other amounts of wear on the other components?
plane engines operate at a some what steady engine speed and most? are air cooled, straight weights are used as not to have ring sticking from the viscosity improvers ,like the recommendation for some marine engines.
Buster viscosity index has no real meaning other than how the oil resists thinning when heated . An oil with lots of viscosity improvers will have a higher vi but under stress the oil "film" will be way less to to the shear. Look at the VI of a straight weight oil.
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