Confessions of a Recovering Thickie

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Mechanician said:
According to Jason - this oil is designed to help. Do you buy the sales pitch in this infomercial?
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I buy that for the most part, fuel dilution is mixing a low-viscosity fluid with one of a higher viscosity. This is independent of brand or type or grade, you're mechanically diluting the oil. No oil resists this better than another.

However, there is also potential damage to the VM by fuel, so there can be a more permanent viscosity loss even if the fuel is partially removed. This is dependent on the quality and type of VM the blender is using.

But to look at a UOA that shows fuel and claim that a particular brand resists mechanical dilution? No.
 
What if you use one grade higher oil due to fuel dilution? The UOA shows viscosity loss equal to one grade ie viscosity of 0w-30 drops to 0w-20.
Am I still violating manufacturer recommendations in US?
 
I’ll use 0-20 and not bat an eye. I have 1 car that saw nothing outside of maxlife syn for its first 85k and doesn’t use a drop @105k. In fact, this car just went from Ohio to Tampa and back and i just drained exactly what I put in, minus the filter on a 5k run.
 
UOA's are absolutely a tool one can use to help measure excessive wear. Additionally, the average joe has nothing else at their disposal, outside a borescope as an indicator. I don't think anyone has said it's the best way, but it is useful.
 
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I've done 8 UOA's over a few years in my truck, just two things I've observed:

- iron is usually in the 2 to 4 ppm/1000k mile range, not 1k range; this is true for most hemis it seems
- the 2 times I ran 5w-20, were the highest reports of iron per 1000 miles. The same formula and driving/usage produced consistently less iron at 0/5w-30.
 
kschachn said:
I buy that for the most part, fuel dilution is mixing a low-viscosity fluid with one of a higher viscosity. This is independent of brand or type or grade, you're mechanically diluting the oil. No oil resists this better than another.

However, there is also potential damage to the VM by fuel, so there can be a more permanent viscosity loss even if the fuel is partially removed. This is dependent on the quality and type of VM the blender is using.

But to look at a UOA that shows fuel and claim that a particular brand resists mechanical dilution? No.
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Yes and not all of the compounds in gasoline burn off, but it does seem that better oils are more resistant to viscosity loss.
 
RDY4WAR said:
UOAs aren't good for comparing wear between different oils. UOAs test the serviceability of the oil. After 100,000 miles of 2 oils (of very different quality and/or viscosity) in identical engines with identical use, both could show consistent 1 ppm/1k miles, but one of them could have far more piston deposits, ring coking, blow-by, oil consumption, seal degradation/leaks, sludge, and varnish than the other. It could also have higher wear that won't show up in UOAs because of the range of particle size the ICP captures and some wear metals getting trapped in carbonaceous deposits as they form. Factors like magnets and bypass filters will skew results.

UOAs also cannot determine the source of wear. Copper could be bearing wear or could just merely be chelation from an oil cooler or brass fitting. Iron could be wear from rings, valvetrain, crank journals, etc... or could be from rust of an iron block. Other forms of analysis like ferrous spectroscopy could better determine these things but now you're getting well outside the scope (and cost) of a UOA.

The only way you can accurately measure wear between 2 oils is with extensively controlled conditions on a dyno with before and after measurements with a profilometer for peaks and valleys on metal surfaces (particularly cylinder walls and rings), adcole machine for measuring cam wear down to a millionth of a inch, and so on. Simulation testing like Te-77 and SRV can give a good idea of that oil's performance, alongside rust, copper corrosion, and other tests.
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Excellent post. Still there are plenty of people who see a difference of 10 or 20 ppm of iron for a 10K run between different oils in their engine and come to the conclusion that the oil with 10 or 20 ppm less iron is the better oil. Then assume their engine is going to last longer with that oil.
 
LSJ said in a recent YT video that oils thicker than manufacturers recomendation may be too thick for the piston rings to properly remove it from the cylinder-walls. That can result in enough oil getting into the combustion to cause problems such as fouled spark-plugs, damaged catalytic converters, and LSPI.

Engines are more complicated than meets the eye. Changing one thing can have several effects that were not initially thought about.
 
JimPghPA said:
LSJ said in a recent YT video that oils thicker than manufacturers recomendation may be too thick for the piston rings to properly remove it from the cylinder-walls. That can result in enough oil getting into the combustion to cause problems such as fouled spark-plugs, damaged catalytic converters, and LSPI.

Engines are more complicated than meets the eye. Changing one thing can have several effects that were not initially thought about.
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Boy, that must be super fun when it's cold then, right?
 
A Blackstone type UOA is too insensitive to see any good wear trends vs oil viscosity used. - it can only see particles 5u microns and smaller. Go find some good SAE studies that measure wear rates much more accurately. There are many studies that show that less wear in some engine components results with higher HTHS viscosity, and the point where the wear starts getting pretty noticeable is around 2.5 cP and below. The AW/AF additive pack and the resulting tribofilm is another factor, but if that is held constant then higher viscosity will result in less wear because the film thickness between moving parts is larger.

Viscosity is a key component to Tribology. Going a grade up from a "recommended" grade of a xW-20 or below is mostly about wear protection headroom, especially if already operating on the ragged edge of MOFT in some components under some use conditions. Some added wear protection headroom never hurts anything.
 
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JimPghPA said:
LSJ said in a recent YT video that oils thicker than manufacturers recomendation may be too thick for the piston rings to properly remove it from the cylinder-walls. That can result in enough oil getting into the combustion to cause problems such as fouled spark-plugs, damaged catalytic converters, and LSPI.
Click to expand...
Seems opposite when engines will typically decrease oil consumption when thicker oil is used. Fouled plugs would mean lots of oil consuption.
 
JimPghPA said:
LSJ said in a recent YT video that oils thicker than manufacturers recomendation may be too thick for the piston rings to properly remove it from the cylinder-walls. That can result in enough oil getting into the combustion to cause problems such as fouled spark-plugs, damaged catalytic converters, and LSPI.

Engines are more complicated than meets the eye. Changing one thing can have several effects that were not initially thought about.
Click to expand...

Then why in Mexico, the same engine that is sold in US allows for thicker viscosity?
 
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