Do Acceptable Wear Limits need to be Lowered?

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An earlier post got me thinking about what is considered "acceptable wear". The limits they show as acceptable is so much higher than what the UOA's show it is laughable at times especially Iron. If people had wear numbers that high members here would have a heart attack and demand immediate engine replacement or a call to the oil analysis company because it must be an error on their part. So how old are these wear limit standards? Were these developed when we used Group I and II oils? Maybe these should be lowered now.
 
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ZZman

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I think it does show wear. But what does it really mean is the question? A teardown would be a better indicator but who wants to do that? So if the metals in the oil are not indicators of wear what are they? How did they get in the oil if they didn't wear off the surfaces?
 
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ZZman

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The link you posted mentions the same thing: "Wear metals" not "Contact or Dissolved metals" I agree with him that it is a better tool for really abnormal wear, contamination issues or trending but that still does not explain why the levels for acceptable are so much higher that what we are seeing in UOA's.
 
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The basic answer here in example form is that people who think they know what they are talking about get all freaked at 10 ppm of Fe vs. 15 ppm of Fe when the 15 ppm Fe could have come from dissolved metal, and the 10 ppm Fe engine could actually have increased wear and much larger particles in circulation - particles that are not caught by a filter, but do not show up in a $20 UOA.
 
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 Originally Posted By: ZZman
I think it does show wear. But what does it really mean is the question? A teardown would be a better indicator but who wants to do that? So if the metals in the oil are not indicators of wear what are they? How did they get in the oil if they didn't wear off the surfaces?
If you really want the facts a teardown is the only way to determine if 150 ppm IRON is too much iron floating around in your oil and causing excessive wear. Remember the recommended PPM results are only based on past UOA results of many other engines and is a very general idea of how an engine wears. The hotter a engine runs the less wear is measured as tested http://books.google.com/books?id=-MooN2D...result&resnum=1 Me personally I have no problems with 150 PPM iron floating around in an extended oil service situation, as long as the other values are in a normal range I/E [email protected], TBN, acceptable limits. I was tounge lashed once before, here for a 40,000 mile UOA with a 56PPM iron report LOL!!! yes many others will want a new engine based on emotional distress, of lack of real world knowledge.
 
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http://www.dysonanalysis.com has a very good list of wear metals levels based on many many years of experience. I suggest that some of our self appointed experts would take a look. they would not get upset and loose sleep and rant when one UOA yields 15 ppm of Fe and the next shows 21 ppm. some of us use UOAs for following trends and serious spikes over the life of an engine. JMTs Ed
 
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I was tounge lashed once before, here for a 40,000 mile UOA with a 56PPM iron report LOL!!! yes many others will want a new engine based on emotional distress, of lack of real world knowledge.(end quote) I'd never run an oil 40k but 56PPm iron over 40K is great.
 
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Buster, that is certainly the case with most well-maintained modern engines, but not all. The following are some current generation engine issues being discussed in the GF-5 committee.
 Quote:
Cylinder Deactivation – Virtually all current General Motors engines use variable valve timing. This is accomplished using camshaft phasing, which can also provide the capability to deactivate the cylinder for improved fuel economy. These VVT systems with hydraulic valve actuation require sufficient engine oil aeration control in order to function properly. • Gasoline Direct Injection – Although not specifically mentioned in the latest GF-5 Needs Statement, nearly all automakers currently have at least one vehicle using GDI engine technology, and CAR estimates that the market penetration of GDI engines will increase from 12% of new vehicles sold in 2011 to nearly 20% in 20169, since GDI can provide 5-10% better fuel economy (10-15% better with turbocharging), and better driving performance, than conventional gasoline engines. GDI engines have shown an increased level of oil contamination by soot, resulting in engine durability and performance issues such as increased timing chain wear and elongation. This issue was raised by JAMA (Japanese Automobile Manufacturers Association) late in the development of ILSAC GF-4, resulting in the adoption of a minimum phosphorus limit (0.06%) for GF-4. It was expected that a Valve Chain Wear test would be developed for GF-5 to address this concern.
 
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It looks like there will be no improvement in wear protection for GF-5 oils. What does need to be improved is deposit control, which is being addressed. People are getting 200k out of most modern engines with minimal problems. Usually it's the other components that end up being a problem.
 
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Buster You're not dumb. Read between the lines. There are wear problems in current generation engines that need to be addressed by the oil, and are being discussed for GF5. Scott "GDI engines have shown an increased level of oil contamination by soot, resulting in engine durability and performance issues such as increased timing chain wear and elongation." "These VVT systems with hydraulic valve actuation require sufficient engine oil aeration control in order to function properly." The first quote is self explanatory. In the second, function properly is code for "journal bearing failures occur."
 
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