Thin vs Thick Discussion, Chapter 10

BeerCan

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Some have said this is worthless data but I cannot ignore it:
Probably not worthless data but also I don't think it is a good wear indicator. UOA IMO are not a tool for tracking engine wear.
Don't get me wrong, I do UOA on almost every oil change I do. Really at best all it tells me that an oil is still serviceable or not.

I mean really what can I glean from one UOA that says 22ppm fe wear against another that say's 28ppm fe wear. I don't drive my vehicles in a lab so no two UOA have exactly the same conditions.

I spend a bit of money on the tests but for me it is just for the fun of it. Maybe I might use the data to extend my intervals but that's all.
 

OVERKILL

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Probably not worthless data but also I don't think it is a good wear indicator. UOA IMO are not a tool for tracking engine wear.
Don't get me wrong, I do UOA on almost every oil change I do. Really at best all it tells me that an oil is still serviceable or not.

I mean really what can I glean from one UOA that says 22ppm fe wear against another that say's 28ppm fe wear. I don't drive my vehicles in a lab so no two UOA have exactly the same conditions.

I spend a bit of money on the tests but for me it is just for the fun of it. Maybe I might use the data to extend my intervals but that's all.

Correct, UOA's are designed to be trended to track a piece of equipment's health so that anomalies stand-out and can trigger an inspection. This can be signs of coolant ingress, a significant uptick in a particular metal, a spike in silicon (and usually wear) that could indicate an air intake tract leak...etc. And of course determine whether the lubricant is suitable for continued use, to maximize ROI.
 

AEHaas

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A UOA may be used to track trends. And in this case the lowering of wear with decreasing viscosity.

It is amazing to me how some people fight so hard to avoid any and all data that a thinner oil may have benefits.

AEHaas
 

BeerCan

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A UOA may be used to track trends. And in this case the lowering of wear with decreasing viscosity.

It is amazing to me how some people fight so hard to avoid any and all data that a thinner oil may have benefits.

AEHaas
No avoiding, I have a vehicle that uses 0w20 and it doesn't bother me a bit. I just try and avoid spurious correlations when I can
 

OVERKILL

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A UOA may be used to track trends. And in this case the lowering of wear with decreasing viscosity.

It is amazing to me how some people fight so hard to avoid any and all data that a thinner oil may have benefits.

AEHaas

They lack the resolution to draw that conclusion. You can't use minute variances in PPM (parts per MILLION) to ascertain whether one lubricant is superior to another, that's not the purpose of the tool, it's like trying to use a chainsaw to perform a breast augmentation, it's simply not precise enough.

That's not to say that you can't get excellent performance out of a thinner lubricant, particularly in applications that call for it, but you can't gauge that performance just using UOA's, it requires tear-down testing and analysis, which is why Doug Hillary did exactly that, while tracking lubricant condition and contamination levels through UOA's when he did his fleet testing for Exxon Mobil. I'm sure if he could have skipped the tear-downs it would have saved a lot of time and money.

His condemnation limit for iron was ~150ppm BTW, over a 90,000Km OCI. A 1.3 million kilometre tear-down yielded both liners and bearings that measured "as new" and were returned to service.
 
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They lack the resolution to draw that conclusion. You can't use minute variances in PPM (parts per MILLION) to ascertain whether one lubricant is superior to another, that's not the purpose of the tool, it's like trying to use a chainsaw to perform a breast augmentation, it's simply not precise enough.
And to add ... the only way to really see a wear metal trend that corresponds to the oil used is to do it on a totally broken in engine. So seeing wear metals "decreasing because I was using thinner oil" on a motor with relatively low mileage on it will be deceiving because the engine is still breaking in and the wear metals will be decreasing from that alone, regardless of what oil viscosity it being used.

I keep meticulous records of fuel mileage on my vehicles, and with my Tacoma I saw a distinct increase in fuel mileage by a solid 2 MPG in the 10K to 11K mileage point, and the higher fuel mileage remained from that point on. I always used the same oil (Mobil 1 5W-30 FS), the same gasoline (Chevron) and drove the same daily 50 mile round trip commute (30% city/70% highway). So IMO the reason for the jump in fuel mileage was the engine was fully broken in and freed up to the point where fuel mileage noticeably jumped up and remained up. It would have been interesting to have also been tracking UOAs to see if the wear metals also decreased corresponding that point in the engine's life.
 
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Another way to increase the flow would be to decrease the resistance of the oil itself by using a thinner oil at that temperature.
Only if there isn't enough flow because the PD is cutting too much flow due to pressure relief. That's pretty hard to determine unless the engine is actually becoming damaged from a lack of lubrication (ie, tear down and inspection required). Or a complete sophisticated engineering analysis and test program is done to ensure all engine components are or are not receiving enough oil flow for proper lubrication.

As mentioned before, just because the pump hits pressure relief doesn't mean there is a lack of lubrication. With oil at operating temperature, there is still lots of oil volume flowing through the engine if the pump hits relief. Most vehicles will barely hit pump pressure relief at full operating oil temperature unless the engine is very near or at redline, like shown with my oil pressure vs RPM graph posted earlier. If it was on the track with that same oil (5W-30 Mobil 1) then as the oil temperature increased it's pretty evident that the pump would never hit pressure relief. Even with a xW-40 or xW-50 oil in track use, the pump still might not hit pressure relief depending on just how hot the oil became.

Interesting that they are using a 30 grade oil, a multi viscosity one at that. And they use the 10 PSI per 1,000 RPM rule of thumb.

AEHaas
If you look at the graph I posted of the on-road oil pressure vs RPM with oil held constant at 200F, you can see it basically follows 10 PSI per 1000 RPM until above about 3000 RPM. But after that it doesn't follow that general rule.
 
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4WD

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A UOA may be used to track trends. And in this case the lowering of wear with decreasing viscosity.

It is amazing to me how some people fight so hard to avoid any and all data that a thinner oil may have benefits.

AEHaas
Well, it was probably that way when you were here many years back ... 0w20 is often associated with economy and nothing else ...
I use it in 3 vehicles ... 2020, 2017, and 2014 ... the later has 140k and does not consume oil ... about the only measure I have ...
Could they do well on 5w30 ?
Sure ... maybe later ...
 
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Have you ever been to the drag races just to watch? On busy days, cars (lots of them street cars) are waiting in the stagging lanes for a long time, and the engines and oil cool way down. These cars are most likely running oil heavier than 0W-20. They push them in the stagging lanes, don't fire them up to move them. When it's their turn to run, they fire up, do a big burn-out, then hammer the engine at WOT and redline down the strip, and I'm sure the oil pump is in relief most of that time. These cars are repeating that many times while there, and race their cars about every weekend. They don't blow-up because the oil pump is in relief.

The people that don't know any better do that... or boosted/nitrous cars. NA engines, like S/SS eliminator classes, run a 0w-8 or 0w-5 as the oil isn't going to get too thin when it never exceeds 150*F. Most Pro Stock teams don't even monitor oil pressure. So long as they have 6.5 gpm flow from the dry sump pump, they send it.

I get a chuckle out of guys with a mild small block running 20w-50 and hitting it cold with 150+ cSt oil. They're just throwing away power.

I like the lowest viscosity that will maintain sufficient film thickness for a given bearing clearance under a given load at a given temperature. Adjust as necessary.
 

OVERKILL

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The people that don't know any better do that... or boosted/nitrous cars. NA engines, like S/SS eliminator classes, run a 0w-8 or 0w-5 as the oil isn't going to get too thin when it never exceeds 150*F. Most Pro Stock teams don't even monitor oil pressure. So long as they have 6.5 gpm flow from the dry sump pump, they send it.

I get a chuckle out of guys with a mild small block running 20w-50 and hitting it cold with 150+ cSt oil. They're just throwing away power.

I like the lowest viscosity that will maintain sufficient film thickness for a given bearing clearance under a given load at a given temperature. Adjust as necessary.

When I used to run my 5.0L, it was my DD, so I'd drive it an hour to the track, make a few passes, then drive it home. The oil was never cold, I mostly ran 0w-40 in it but did experiment with using thinner oils (0w-20) in the colder months. Relief pressure was 65psi IIRC and it would be on the relief by 4,500 with the 0w-40.

I know some of the folks that trailered their rigs in and were doing periodic tear-downs were using much thinner stuff, but I wasn't inclined to run mine hard with a 150,000 mile stock bottom end on the 0w-20 I had played around with.
 
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The people that don't know any better do that...
Yep ... I was mainly talking about people that drove their every day street cars, trucks and motorcycles to the drag races - which there were many. A cold Friday or Saturday night with 200+ cars at the strip means they sit for a long time in the staging lanes before firing up, doing a burn-out and hammering it at redline down the 1/4 mile. Agree that many didn't know any better. The PD pump did it's job, even though it was probably in pressure relief all the way down the 1/4 mile.
 
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Yep ... I was mainly talking about people that drove their every day street cars, trucks and motorcycles to the drag races - which there were many. A cold Friday or Saturday night with 200+ cars at the strip means they sit for a long time in the staging lanes before firing up, doing a burn-out and hammering it at redline down the 1/4 mile. Agree that many didn't know any better. The PD pump did it's job, even though it was probably in pressure relief all the way down the 1/4 mile.

Particularly EFI cars as a lot of them are still in "warm up" mode until about 160*F. The air/fuel ratio is richer and timing usually retarded a bit. They'd actually run quicker to let it heat up to at least 160*F before pulling into the burnout box.
 

MolaKule

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Another thing about the graph. If that amount of flow is required by the average engine then thicker and thicker oils at freezing temperatures would get little or no flow. It is not fair to say you need that flow and then say a nice thick oil will stick to engine parts and not fall off and that there will be plenty of flow regardless of the freezing temperatures. "Thick oil flows just as well as thin oil but lubricates better" "Regardless of the oil temperature the flow is exactly the same." I do not believe these.

AEHaas
I must have missed it but where in this thread was adhesion discussed?
 
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