Wear is wear...right?

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deeter16317

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OK, I'm not going to even bring up an oil brand...this is completely hypothetical:

Say you have Conventional 15w40 (OIL A) and a Full Synthetic 15w40 (OIL B). Assume you sample under the same operating conditions...

You complete UOAs on the same engine, two different times and the UOAs look, for all intents and purposes, identical...

Both the UOA of OIL A and OIL B have the same ppm of all the major wear metals (FE, PB, CU, etc)...again, lets assume wear metals are within the same order of magnitude (ie. 12ppm vs 11ppm, not 12ppm versus 123ppm)...

Which is wearing "better"? And why?

Thoughts?
 
Oil analysis is best used when trending. Some believe in the school of thought that oil analysis is not a good tool to compare motor oils. You also have to consider varnish, sludge and deposit protection, something you are not going to get with a $20 spectrographic analysis report.

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Oil analysis can not be used to compare wear characteristics between oils. The biggest problem is that particles greater than 5 microns in size are not detectable using these simple analytical techniques, so an oil which has a more severe wear problem and is generating wear debris in larger particle sizes, will appear in oil analysis to have lower wear numbers. It is useful to establish a baseline and watch for significant variations which indicate mechanical problems or checking alkalinity and viscosity to determine useful oil life. In some engines Red Line does have greater lead numbers which is an interaction with the molybdenum. It is small amounts on the surface and does not cause premature bearing wear.
 
SO your saying that an oil that is causing an engine to shed 12ppm of FE could potentially wear out faster than another oil that's causing the engine to shed 12ppm of FE?

I guess this is the part I don't understand...you only have so much "wear metal" to wear, at which point the engine becomes "worn out"...
 
Originally Posted By: deeter16317
SO your saying that an oil that is causing an engine to shed 12ppm of FE could potentially wear out faster than another oil that's causing the engine to shed 12ppm of FE?

I guess this is the part I don't understand...you only have so much "wear metal" to wear, at which point the engine becomes "worn out"...


You want to be within "normal range" when it comes to wear metals. You also want good viscosity stability, deposit and sludge control which are all related. Whether an engine wears out faster due to slighly higher wear metals is completely theoretical. You simply can not determine this IMO.
 
I guess I just don't see this...

I get told all the time (not on this forum) that synthetics cause less wear than conventional; however, I can put a UOA showing similar numbers from a conventional oil, sometimes better...so which is wearing better? Or which is protecting better?
 
I'd take that Redline statement with a grain of salt. It's partially true, but also it's a Redline defending statement, made by the Redline chemist. The true part is that just because you have 10 ppm (or whatever) amount of "dissolved" metal detected, does not mean all 10 ppm came from metal-metal contact (ie contact wear).

And in practice when you have "particles greater than 5 microns in size" even though they may not be detectable as dissolved PPM, these particle will cause elevated wear numbers....especially if not caught in the oil filter.

Wear is also not linear.
 
Originally Posted By: Pablo
I'd take that Redline statement with a grain of salt. It's partially true, but also it's a Redline defending statement, made by the Redline chemist. The true part is that just because you have 10 ppm (or whatever) amount of "dissolved" metal detected, does not mean all 10 ppm came from metal-metal contact (ie contact wear).

And in practice when you have "particles greater than 5 microns in size" even though they may not be detectable as dissolved PPM, these particle will cause elevated wear numbers....especially if not caught in the oil filter.

Wear is also not linear.


True. Good point. It is a RL defending statement.

One would have to think that if wear metals are high with a certain product, that the company/chemist would reformulate it? Then again, maybe Redline in a 500 hp engine on the track is going to provide more shear stablity and protection than a conventional oil. So a lot of it could depend on the situation you are using a particular product in. Drive back and forth to work, a cheap conventional is probably all most of us need.

It does appear that conventional oils show among the lowest wear metals in UOA's fwiw. Up to a given mileage point though, usually no more than 7k mile intervals.
 
Most wear occurs on a cold start because you have no oil pressure for a few seconds. Synthetics flow twice as fast (hypothetically) = twice less wear...

Heck if your engine is like a big rig that never gets turned off, it doesn't really matter if you go dino or synthetic.

Some of the metal "wear" can get trapped in the oil filter (especially if you have a bypass filter) and those will never show up in the UOA.
 
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Originally Posted By: buster
[
It does appear that conventional oils show among the lowest wear metals in UOA's fwiw. Up to a given mileage point though, usually no more than 7k mile intervals.



My UOAs are up to 10k miles, but it is also a 4.5 gallon sump with a bypass, not a 5 quart sump like many cars. Actually, I had 30k on part of the oil remaining in my sump the last go around.

I see what you're saying, sort of...you can have larger particles that aren't counted in the analytical. But at the same time, you'd expect to see higher wear metals associated with that oil containing particles since they are creating wear themselves, correct?

I guess I just hear too generally that a synthetic will produce lower wear numbers than a conventional...I just never see those UOAs proving that.
 
But you're right, as long as you're filtering both engines the same and changing them at the same time, the wear should theoretically be the same. At that point you can argue that synthetic offers a little better lubrication because all the molecules are the same size vs. dino where molecular size varies. But I think that would be somewhat neglibible.
 
Originally Posted By: wcbcruzer
Most wear occurs on a cold start because you have no oil pressure for a few seconds. Synthetics flow twice as fast (hypothetically) = twice less wear...

Heck if your engine is like a big rig that never gets turned off, it doesn't really matter if you go dino or synthetic.

Some of the metal "wear" can get trapped in the oil filter (especially if you have a bypass filter) and those will never show up in the UOA.



It depends on the temperature whether or not a synthetic will flow "quicker". It sounds like a synthetic flowing 2x as fast is a myth- it all depends on what temp...
I believe wear is wear. I have also had better uoa's with dino's like 76 and delo. So, for me I am going to stick with what the results show as opposed to something I am told, or what the general population says. Remember- what someone tells you is not always the truth. It is usually what they know to be the truth. Two totally different things...
JMO
 
From the link JAG posted:

Quote:
Why does the UOA not reflect the amount of iron powder caught by the magnet. Is the magnet removing ALL the iron from mechanical wear? The ppm/mile in the UOA for this summer interval was the same as last year's, but the magnet had three times as much stuff on it. Could the UOA only be detecting iron corrosion, with my magnet removing all the wear particles?



Quote:
Gman,

In these cases, I'd normally recommend doing a particle count to see if the thinner lube is generating significantly more wear. Spectrographic analysis is sort of a blunt instrument when trying to pin down specific types of wear mechanisms.

Ted
 
I remember a UOA of a truck that had a good coolant leak for awhile and had wear numbers over 2000ppm. The truck was still running...not well...but running. So I think debating if one oil shows 12ppm and another were to show 20ppm is splitting hairs. Especially when you factor in typical testing noise, collection techniques, leftover oil in the engine, etc. It's even less meaningful with only a singe OCI on each oil.

Bruce has stated that he only worries if Fe is greater than 50ppm, and he has seen more testing than all of us put together.
 
Despite OA being a somewhat limited tool, I'd still want low wear metals in a report. Things just need to be kept in perspective when not knowing particle size etc.
 
"SO your saying that an oil that is causing an engine to shed 12ppm of FE could potentially wear out faster than another oil that's causing the engine to shed 12ppm of FE?"

Lots of variables here, although one should be able to discount a number of them in order to do a comparison. 12ppm of what Fe ? Cams/followers, piston rings, timing chain, timing gears, how many cam followers, how many cylinders, etc ? A common discussion is how poorly some of the new formulations protect some cam/follower designs. Also, some level of 'wear' appears to be readily tolerated in some designs, considering that 500k mile Cummins 5.9L I6 turbodiesels aren't uncommon, and 1 million mile ones aren't that rare, all the while shedding Fe at rates that would have Honda owners lashing themselves while wearing sackcloth.

You need to do trending, and you need to be looking at how much Fe has been added at each interval as opposed to just adding a new sample into an average. Some articles on ZDDP indicate that Fe gets incorporated into films, some oils seem to be designed to do more cleaning than others, so some oils probably generate more apparent 'wear' because they keep more Fe in solution. Also remember that even in this forum there have been engines with good UOAs that ended up sludged.
 
Originally Posted By: 1sttruck
"SO your saying that an oil that is causing an engine to shed 12ppm of FE could potentially wear out faster than another oil that's causing the engine to shed 12ppm of FE?"

Lots of variables here, although one should be able to discount a number of them in order to do a comparison. 12ppm of what Fe ? Cams/followers, piston rings, timing chain, timing gears, how many cam followers, how many cylinders, etc ? A common discussion is how poorly some of the new formulations protect some cam/follower designs. Also, some level of 'wear' appears to be readily tolerated in some designs, considering that 500k mile Cummins 5.9L I6 turbodiesels aren't uncommon, and 1 million mile ones aren't that rare, all the while shedding Fe at rates that would have Honda owners lashing themselves while wearing sackcloth.

You need to do trending, and you need to be looking at how much Fe has been added at each interval as opposed to just adding a new sample into an average. Some articles on ZDDP indicate that Fe gets incorporated into films, some oils seem to be designed to do more cleaning than others, so some oils probably generate more apparent 'wear' because they keep more Fe in solution. Also remember that even in this forum there have been engines with good UOAs that ended up sludged.


thumbsup2.gif
 
Originally Posted By: 1sttruck
Also remember that even in this forum there have been engines with good UOAs that ended up sludged.


UOA helps indicate what comes out in the oil; what stays in the engine does not show up in UOA.
 
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So basically the only thing that a UOA is good for is looking at the condition of the oil, and whether it is still serviceable or not? It has no direct indication of the actual engine's condition?

From what I have gathered here, the "analysis" of the wear metals that a lab provides are more/less educated guesses and may not be real? The data is real, but their interpretation of the data is a guess?

Hmmm, guess I ought to quit viewing UOAs as importantly as I have been. My "nicely wearing engine" UOAs don't seem as neat now...
 
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