UOA's versus Jim Fitch, et al!

[Terry]

1911, you bring up some good valid points from your engineering background. And most scientists and engineers not specifically adept or experienced in automotive oil analysis experience the screaming feeling that this is bullhocky.

I agree with this comment; "vast majority of members on this board are grossly misusing and over-interpreting the data they get from basic UOA's." If they haven't a accurate interpretation this comment is absolutely correct.

Your progressive and predictable theory is wonderful and on a test stand in a controlled environment would work, mostly.

Lubricants are very good at controlling wear rates from these smaller particles mentioned here, ( I have not read Fitches comments, yet).

This protective Micelle or micel affect can disrupt the predictive and measureable method your math desires. Add environmental affects, variable RPM, and many other aspects and the variables become nearly uncontrollable with low cost technology to measure.

If a data base or experienced analyst has access to data from more scientific capabilities of testing lubes and engines and compares/correlates that to the BASIC UOA we see here then he or she may have a good basis at tracking and making predictions.

That person would be recluctant to give that kind of knowledge away.

More later, have to head to Church.

TD

 

[TooSlick]

The correlation of service intervals to wear rates is very different in diesel engines than in gas engines, due to the presence of highly abrasive soot particles.

For example, even a low soot concentration of 1.0% is equal to 10,000 ppm of soot! This is several orders of magnitude higher than the highest concentration of silicon or iron particles I've ever seen in any normal analysis....

UOA's are primarily measuring the concentration of dissolved irons and particles < 5 um. Even if these concentration look fairly high, they do NOT bootstrap the wear rate to any measurable degree. It is the change in viscosity and depletion of the additive package that is most to blame for wear rates that go non-linear over time and not solid particulates - at least in on-road applications.

Tooslick

 

[ekpolk]

quote:

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Originally posted by 1911:
{snip}

I'm not here to make friends but to stimulate thought (and clearer thought) and to get the experts to tell come out of the woodwork and speak the truth. I was successful in doing that here and hopefully, some people (including the oh so smart scientists) also got to learn some 9th or 10th grade math that in reality should be extremely intuitive to them.

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Well, since you're not here to make friends, you won't be offended if I note that while your math may surpass the 10th grade level, your spelling and composition (or maybe just typing...) don't.

Oh by the way, although I have done several of them myself, I consider UOA, especially the way an individual must do them (non-statistically significant sampling) to be little more than a general monitoring tool. I also happen to go the extra distance and order particle counts with mine (usually). I'm much more interested in getting an idea of the size of the chunks floating around in my oil than I am of being generally aware of the mix of elements (though a spike in one or another, e.g. lead, might be telling).

This really is a great forum. While you certainly don't need to suck up to anyone, you can still stimulate thought and make a friend or two while you're at it. Interesting info; thanks.

 

[1sttruck]

"On the topic of filter analysis this is where most people are missing the boat. There is as much information in an oil filter as there is in an oil analysis!"

Particles in the oil filter, larger particles in the oil not incorporated in the UOA, and metals incorporated in sludge/varnish/films inside of the engine. 'Wear' estimates ideally start with a cleaning process of some sort so metals from prior use aren't included in the present samples, samples over a period of time with metal quantity estimates from particles, another cleaning where the metals are collected and more estimates made on metal quantity to be included in the sample interval. I guess that's why UOAs aren't often used for wear analysis.

More than a coupld of oil suppliers have noted that using their oil will flush previously deposited films and result in higher than typical UOAs until the engines are cleaned out.

 

[Terry]

Areas to amplify a bit;

MODERN Oil formulation: Critical to interrupting linear wear rates AND dispersed contaminants < 10 um. MY OPINION from much professional < not academic> APPLIED science in this field, is that appropriate chemistry can handle the smaller particles well enough to inhibit wear effectively to ELIMINATE or reduce the need to filter to < 10 um.

As Too Slick mentions rightly so,diesel fuel soot is a harder problem to solve. SOMETIMES a bypass or fine filtration system can be justified to enable longer/safe drains. MOST SMALL DIESELS DO NOT NEED bypass filtration. Controlling initial soot production, solublizing soot formations that is developed by safely and properly dispersing, through the mechanism of a solublizing add mitigates the need to filter that "finely" in pickup truck or passenger car diesels.

Automated spectrographic "used" oil analysis process,interpretation, accuracy:

1911, simply put and alluded to in the earlier post. I have found through proprietary theoretical application over years of use, that BASIC, SIMPLE, AFFORDABLE, uoa, CAN be used to determine the oil condition,wear rates,combustion efficiency,unit condition,and the probable causes of all these aspects of the analysis.

Since most spectrographic analysis is automated it is very accurate vs. cost benefit, not to mention availablilty to the customer.

Comparing lube bench tests to various lube formulation tribo functions to known unit wear rates catalogued by BOTH generic engine databases and actual field tested universal averages ,SHOULD enable the experienced interpreting tribologist/analyst ,through a blend of art and science to properly interpreted results.

The FACT that very few in the automotive field can accomplish this is more a testament to the breadth and scope of control by entrenched interests than science or math ability.

Ideally, having 100% perfectly clean lube oil, 100% of the time should eliminate automotive engine wear.

Being a self combusting air pump it ingests ambient air that is contaminated and is fueled by combustable fuel that is not perfectly clean either. Add in design problems and the variability reintroduces itself to you the mathmaticican !

Terry

[ September 13, 2005, 12:53 PM: Message edited by: Terry ]

 

[Terry]

TooSlick said; "UOA's are primarily measuring the concentration of dissolved irons and particles < 5 um. Even if these concentration look fairly high, they do NOT bootstrap the wear rate to any measurable degree "

It is not readily available nor offered academcially for public display but don't kid yourself Ted, it exists. That um level should be corrected to
Large particle ID and counting corrects in a cost effective way the larger component and why our premium kit offers it if needed.

Terry