double post........my apologies
5w-20 and engine longevity
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I believe Dans spreadsheet is data only from Ford modular engines Fernando.
Anyhoo, I dunno! If I had a car that speced 5w-20, I'd most likely use it, esecially for cold weather short trippin. The grade does intrigue me for power increase and fuel efficiency gains. But I just can't bring myself to put it in either of my Yotas, especially the 94 Corolla. Don't solid lifter/shim over bucket designs prefer a thicker oil? If I KNEW unequiveckly that it wouldn't produce more wear, Id use it. That car needs all the help it can get power wise! UOA reports............well, is a difference of a few ppm really indicative of a measurebale loss of metal on a wear part?
Like Buster says, most likely no. Goodness, I'm weary of putting 5w-20 in an automobile that is worth 1/4 what AEHAAS's Ferarri engine is worth
Anyhoo, I dunno! If I had a car that speced 5w-20, I'd most likely use it, esecially for cold weather short trippin. The grade does intrigue me for power increase and fuel efficiency gains. But I just can't bring myself to put it in either of my Yotas, especially the 94 Corolla. Don't solid lifter/shim over bucket designs prefer a thicker oil? If I KNEW unequiveckly that it wouldn't produce more wear, Id use it. That car needs all the help it can get power wise! UOA reports............well, is a difference of a few ppm really indicative of a measurebale loss of metal on a wear part?
Why not start with the manufactures recomendation and work from their. It seems like a reasonable person would not have an issue with someone starting with the OEM recomendation then useing UOA to work up. Surely we can all see that while 5W20 might very well work fine in those applications that recomend it their might be a better choice for each individual application. The OEM recomendations make a lot of assumptions that are not going to apply to all end users.
If one closely looks at most owners manuals the wording most often used in reguards to oil viscosity is "recomends,recomended or recomendations" that is far from a cst in stone decree even if no other choices are given!
If one closely looks at most owners manuals the wording most often used in reguards to oil viscosity is "recomends,recomended or recomendations" that is far from a cst in stone decree even if no other choices are given!
Here's Quick Lude's diesel UOA, showing only modest increases in Pb, Sn, and Cu with oil at 8.9 cst from fuel dilution..
Fuel-diluted to SAE 20 in a diesel engine
What's interesting is that Cr is lowest in the two used oil analysis with the lowest viscosity. Maybe the claim that 5w20 puts more oil under the upper ring is true, though I don't think the numbers are statistically significant. It would be worth looking at Cr values for 5w20 vs 10w30 or thicker, to see if 5w20 is best at protecting the upper ring. That's a part that when it wears out, you get reduced fuel economy.
Fuel-diluted to SAE 20 in a diesel engine
What's interesting is that Cr is lowest in the two used oil analysis with the lowest viscosity. Maybe the claim that 5w20 puts more oil under the upper ring is true, though I don't think the numbers are statistically significant. It would be worth looking at Cr values for 5w20 vs 10w30 or thicker, to see if 5w20 is best at protecting the upper ring. That's a part that when it wears out, you get reduced fuel economy.
With comparison samples of 10 or so it only takes 1 problem motors to throw the whole scale off. Though interesting, there just isn't enough info here to draw any conclusions. 5w20 may show less wear in a casually driven car but more in the same spirited driven one. The reason I pointed to the 10w30 is why argue for 5w30 when the 10w30 shows the greatest jump in performance. I'm using 5w20 while under warranty and not worrying about it. I don't think FE is the beast indicator for viscosity anyway. Cr, Al and Pb would interest me more. Bearings and rings.
"With comparison samples of 10 or so it only takes 1 problem motors to throw the whole scale off. Though interesting, there just isn't enough info here to draw any conclusions." I agree. So, until a larger sample can be drawn, we're still consigned to largely anecdotal evidence and a few used oil analysis, which at first blush seem to indicate that 5w-20, particularly Motorcraft, Mobil 1 and Amsoil, protects engines that are not abused or used for racing sufficiently.
"This is why I argue that a larger sample might be more illuminary, but not absolutely conclusive i.e. "proof.""
This is a moot point as it's a common stumbling block for people, and we aren't really trying to 'prove' anything. DarkDn's numbers just seem to reinforce what we tend to see when we step back and look at engine wear vs oil visocsity, and that is more wear with lighter oils. It's supported by what seem to be common maker's recommendations for heavier oils outside of the US even if they recommend 5w20 or whatever in the US, racers who value engine life over at least a season using heavier oils, endurance racers using heavier oils, diesels, motorcycles, boats, etc., using heavier oils, and pretty much the rest of the world outside of the US and/or North America using heavier oils.
What's good enough is different than what is best.
This is a moot point as it's a common stumbling block for people, and we aren't really trying to 'prove' anything. DarkDn's numbers just seem to reinforce what we tend to see when we step back and look at engine wear vs oil visocsity, and that is more wear with lighter oils. It's supported by what seem to be common maker's recommendations for heavier oils outside of the US even if they recommend 5w20 or whatever in the US, racers who value engine life over at least a season using heavier oils, endurance racers using heavier oils, diesels, motorcycles, boats, etc., using heavier oils, and pretty much the rest of the world outside of the US and/or North America using heavier oils.
What's good enough is different than what is best.
Ted very well said.
bruce
bruce
Ted is correct. I think it's also important to consider improvements in engine design/materials that allow for thinner lubricants. For all we know, some of these engines could "potentially" run on xw-10 oils. So it's not always the oil at play, but engine design.
According to Amsoil, the last time I spoke with them they said the film thickenss isn't much different between a 20wt and a 30wt oil so you won't see much of a difference.
*BTW, they told me that S2k 0w30 will NOT have the GF-4 rating.
According to Amsoil, the last time I spoke with them they said the film thickenss isn't much different between a 20wt and a 30wt oil so you won't see much of a difference.
*BTW, they told me that S2k 0w30 will NOT have the GF-4 rating.
I have a book from the 1960's that says SAE 20 is used in summer, 10W in winter, and sometimes 5W if it's really cold. SAE 30 is for engines that are worn out, and burn oil.
Hi,
Ted you said -
"A thinner oil decreases oil pressure..........."
This is not strictly correct and IMHO may confuse some people. Operating OP is determined by a number of things but primarily by engine design (and influenced by condition) and the controlled operating components such as the OP relief valve etc. Oil flow is constant regardless of the oil's viscosity and OP losses especially at idle should not be used to judge an engine/oil operating "viscosity". Most engine manufacturers are usually happy with around 0.5-1bar OP at idle speed. Mostly, "factory specification" OP is measured at around 3/4 of maximum revs or above
For instance, it is usually possible to get exactly the same OP at 4-5000rpm from all of the oils listed in a Manufacturer's Handbook (between say 5w-20 and 15w40, or perhaps 0w30 and 20w-50) when measured "clinically" using the Manufacturer's stipulated test protocols including an oil temperature usually bracketed as say 80C-100C. Admittedly sometimes a "test" oil viscoity is mandated but this is rare today
Buster - you said;
"According to Amsoil, the last time I spoke with them they said the film thickenss isn't much different between a 20wt and a 30wt oil so you won't see much of a difference."
Well of course this is simply not correct. It is the whole "issue" of establishing the HTHS viscosity test protocols and why it forms one critical building block of the ACEA's oil Quality rating system. And remember that ACEA is vehicle and engine manufacturer driven unlike the API which is primarily Oil Company controlled
As you know, GC is one example of a SAE30 oil with a HTHS vis of around 3.5cSt - most SAE30 oils will not pass the A3/B3 test protocol and very few SAE30 oils are so rated. I do not know of an SAE20 oil that is rated A3/B3
I would be very happy using a 5w-20 synthetic oil in any engine if the Manufacturer has specified and Approved it
Doug
Ted you said -
"A thinner oil decreases oil pressure..........."
This is not strictly correct and IMHO may confuse some people. Operating OP is determined by a number of things but primarily by engine design (and influenced by condition) and the controlled operating components such as the OP relief valve etc. Oil flow is constant regardless of the oil's viscosity and OP losses especially at idle should not be used to judge an engine/oil operating "viscosity". Most engine manufacturers are usually happy with around 0.5-1bar OP at idle speed. Mostly, "factory specification" OP is measured at around 3/4 of maximum revs or above
For instance, it is usually possible to get exactly the same OP at 4-5000rpm from all of the oils listed in a Manufacturer's Handbook (between say 5w-20 and 15w40, or perhaps 0w30 and 20w-50) when measured "clinically" using the Manufacturer's stipulated test protocols including an oil temperature usually bracketed as say 80C-100C. Admittedly sometimes a "test" oil viscoity is mandated but this is rare today
Buster - you said;
"According to Amsoil, the last time I spoke with them they said the film thickenss isn't much different between a 20wt and a 30wt oil so you won't see much of a difference."
Well of course this is simply not correct. It is the whole "issue" of establishing the HTHS viscosity test protocols and why it forms one critical building block of the ACEA's oil Quality rating system. And remember that ACEA is vehicle and engine manufacturer driven unlike the API which is primarily Oil Company controlled
As you know, GC is one example of a SAE30 oil with a HTHS vis of around 3.5cSt - most SAE30 oils will not pass the A3/B3 test protocol and very few SAE30 oils are so rated. I do not know of an SAE20 oil that is rated A3/B3
I would be very happy using a 5w-20 synthetic oil in any engine if the Manufacturer has specified and Approved it
Doug
Thinking of the statistics in this and the tendency of extremes to skew things....
Has anyone just tried using the MEDIAN instead of the average? That tends to even out numbers, although one would want to bear in mind the M1 effect on 0W20.
Even if the results are crap, I'd be interested in the medians.
Has anyone just tried using the MEDIAN instead of the average? That tends to even out numbers, although one would want to bear in mind the M1 effect on 0W20.
Even if the results are crap, I'd be interested in the medians.
"In the same engine under the same conditions, a significantly thinner oil will reduce oil pressure..."
I would add however, that a low viscosity lubricant will also typically reduce average oil temps. The difference in dropping down one SAE grade is normally a 5F-10F reduction in equilibrium oil temps. So the difference in oil pressure between say a 5w30 and a 5w-40 is not as great as the difference in HT/HS viscosity - which is measured at the same 150C/302F temp.
The temperature "equivalency" between each successive SAE grade in terms of oil thickness is about 20F/10C. For example, the following "mid-grade" SAE samples would yield approx the same oil pressure:
xw-20; running @ 190F
xw-30; running @ 210F
xw-40; running @ 230F
xw-50; running @ 250F
All things being equal, the thinner oil running at the lower temp is preferred. Significantly lower fluid temps will reduce wear and also extend the life of elastomeric seals/gaskets....
I would add however, that a low viscosity lubricant will also typically reduce average oil temps. The difference in dropping down one SAE grade is normally a 5F-10F reduction in equilibrium oil temps. So the difference in oil pressure between say a 5w30 and a 5w-40 is not as great as the difference in HT/HS viscosity - which is measured at the same 150C/302F temp.
The temperature "equivalency" between each successive SAE grade in terms of oil thickness is about 20F/10C. For example, the following "mid-grade" SAE samples would yield approx the same oil pressure:
xw-20; running @ 190F
xw-30; running @ 210F
xw-40; running @ 230F
xw-50; running @ 250F
All things being equal, the thinner oil running at the lower temp is preferred. Significantly lower fluid temps will reduce wear and also extend the life of elastomeric seals/gaskets....
"This is not strictly correct and IMHO may confuse some people. Operating OP is determined by a number of things but primarily by engine design (and influenced by condition) and the controlled operating components such as the OP relief valve etc. Oil flow is constant regardless of the oil's viscosity"
Operating pressure is also regulated bye bearing clearence. large clerance equals low presure high flow, low clerance high presure low flow.
Not a hydraulic engineer but I did this example
today in our bulk lube plant as follows,
Pump base oil from one tank to other tank.
pumping same oil, same temp, same day.
pumping with all valves open gave highest flow rate 130 GPM with lowest presure about 5 psi.
Pumping with valves part closed gave lower flow
50 GPM with highwer presure 10 PSI
kinda what ted said only valves would be bearing clearance.
bruce
Operating pressure is also regulated bye bearing clearence. large clerance equals low presure high flow, low clerance high presure low flow.
Not a hydraulic engineer but I did this example
today in our bulk lube plant as follows,
Pump base oil from one tank to other tank.
pumping same oil, same temp, same day.
pumping with all valves open gave highest flow rate 130 GPM with lowest presure about 5 psi.
Pumping with valves part closed gave lower flow
50 GPM with highwer presure 10 PSI
kinda what ted said only valves would be bearing clearance.
bruce
I've been reading all of this with interest, since I've been one of those who is leery of xW-20 vs. xW-30. I'm trying really hard to become a fan of xW-20, and am attempting to be as open minded as I can, despite my intial trepidation about using such a thin oil. Although some evidence seems to point to better wear with xW-30, a lot of used oil analysis on this board seem to indicate that xW-20 is doing a good job.
I have a new '05 Mustang GT, and am very interested in getting this engine started "right". I've spoken to a trusted mechanic, and he does not endorse xW-20, but for a different reason than wear. His lack of confidence in lighter oils is the sludge factor. He believes that lighter oils, being more volatile, will be more apt to form sludge in internal passageways.
Having said all this, my question to all the gurus here, is this:
While used oil analysis for xW-20 show good wear numbers, would any used oil analysis show evidence of sludge buildup? If not, I wonder if someone could be smiling due to good used oil analysis up until his oil galleys plug up with sludge and cause his engine to grenade.
Or, are modern oils (especially synthetic) good enough so one needen't worry about this? So, to sum up, can a used oil analysis show sludge starting to form, or not?
I have a new '05 Mustang GT, and am very interested in getting this engine started "right". I've spoken to a trusted mechanic, and he does not endorse xW-20, but for a different reason than wear. His lack of confidence in lighter oils is the sludge factor. He believes that lighter oils, being more volatile, will be more apt to form sludge in internal passageways.
Having said all this, my question to all the gurus here, is this:
While used oil analysis for xW-20 show good wear numbers, would any used oil analysis show evidence of sludge buildup? If not, I wonder if someone could be smiling due to good used oil analysis up until his oil galleys plug up with sludge and cause his engine to grenade.
Or, are modern oils (especially synthetic) good enough so one needen't worry about this? So, to sum up, can a used oil analysis show sludge starting to form, or not?
rainman - That's the problem with trusted mechanics. They can be usually right, then come up with a ridiculous zinger, and momentum makes you believe it.
Principals as "Boundary Lubrication" refer to pure lubricating fluid properties and probably have no place in the discussion of modern motor oils. I believe that todays base oils act more as a vehicle for additives than as lubricants.
There are anti-wear additives each working at different temperatures within a motor oil. There are similar anti-friction additives. These and other additives are the workhorses of metal to metal protection.
Base oils act more as coolants and a review of my later chapters shows why there is more flow with thinner oils. As stated above temperature is a major factor in wear equations.
Oil pressure is insignificant in automotive lubrication. The separation (of parts) pressure of oil in a bearing is several thousand pounds verses the feed pressure of tens of pounds. Flow is however important, regardless of the pressure.
This is why oil is so interesting to me. As much as we know there is more misunderstood.
aehaas
There are anti-wear additives each working at different temperatures within a motor oil. There are similar anti-friction additives. These and other additives are the workhorses of metal to metal protection.
Base oils act more as coolants and a review of my later chapters shows why there is more flow with thinner oils. As stated above temperature is a major factor in wear equations.
Oil pressure is insignificant in automotive lubrication. The separation (of parts) pressure of oil in a bearing is several thousand pounds verses the feed pressure of tens of pounds. Flow is however important, regardless of the pressure.
This is why oil is so interesting to me. As much as we know there is more misunderstood.
aehaas
Boundary Lubrication needs FM/AW additives for protection in full hydrodynamic lubrication base oil is main lubricant.
bruce
bruce
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