synthetics, filtration, wear metals: a perspective

[Doug Hillary]

Hi,
for what it is worth, this data concerning my DD Series 60 diesels may be of interest;

1 - A well known mineral 15W-40 HDEO was at condemnation point at around 22kkms (cost $3 per ltr)
2 - A semi-synthetic 15W-40 HDEO was at condemnation point at around 40kkms (cost $4.50 per ltr)
3 - A fully synthetic 5W-40 HDEO was at condemnation point at around 90kkms (engine fitted with by-pass centrifuge)(cost $9 per ltr)

Note A - Engine manufacturers prescribed OCI of 15kkms when using an Approved lubricant

Note B - The condemnation point with 1 and 2 above was thickening out of engine manufacturer's limits

Note C - The condemnation points with 3 above was either of Iron or Soot at or above engine manufacturer's limits. The viscosity was always within limits

The economic break even point of the synthetic/centrifuge combination occurred for me at 70kkms over the semi-synthetic (and four years or 1m kms retention of vehicle). Other benefits with 1 above were better engine cleanliness, less wear of valve train components and easier starting in sub-zero temperatures throughout the OCI cycle

Hundreds of UOAs on my own database support these comments

 

[Steve S]

The "dino" oils of the past 10 + years have allowed 250,000+ mile engine life. And adding that many change the syn oil at "Dino" oil intervals or very close to it thus not needing or taking advantage of the syn oil properties, For those syn oil is a total waste of their money but then it is their money "like buying a K@N air filter and expecting good things will happen" . What Doug says but in my perspective.

 

[Gary Allan]

Originally Posted By: TeeDub
With regards to point #2 above, the argument simply makes NO sense at all. If a lubricated, mechanical component wears at a slower rate and stays cleaner internally (a bypass filter helps here by removing by-products of oil oxidation), it will last longer and need fewer repairs.


I think he's just mirroring what Doug Hillary told us in his commercial use of synthetics over his competitors (that were also customers in fleet maintenance) that were using conventional. He used centrifuges ..they used bypass filters. They both used UOA to determine change out and top up rates. His use of synthetics resulted in no significant engine life extension. It did result in 1/4 to 1/5 the down time for oil changes.

That's just a sensible exchange of formula components using the same outcome as an anchored result. 1lb moving 55,000 ft vs. 55,000 lbs moving 1 foot. If you un-tether the result ..then the exchange isn't so straight forward.

In practical terms, very few are going to be able to filter the variables out like straight forward commercial service does. One can certainly say that without bypass filtration you can't run out synthetics to their end of life state without undue damage. One can say that you can't run conventional oils out to the same end of life that synthetics can go, with or without bypass filtration, without undue damage. What they both do is contain the engine, in terms of lubrication, in an acceptable operational envelope over vastly different spans.

Now move that down to a Power Stroke or Cummins owner who isn't in outright commercial service where longer term maintenance issues can rear their ugly head ..and the view may be altered a great deal. Who wants EGR or other issues 2 years after the warranty is out??

 

[pickled]

I'm all about the instantaneous wear rate/stress on the system...I want the derivative not an integration to decide my oil choices for long term ownership models. Short term ownership cries out for integral.

 

[pickled]

Hi Doug,

My findings over many fleet models parallel your own. Ownership costs and overall equipment effectiveness were improved via synthetics and bypass/centrifuge on all occasions except the turn and burn fleet ownership models (i.e. 100% leased turned back in at 3 years).

 

[Doug Hillary]

Hi,
pickled - Good to hear of similar results to what was achieved in testing and operations here over many many years

In the case of the MANN-Hummel centrifuges - their break even point was about 2.5 years as I recall. They could be "relocated" on to similar engines too which was a great cost savings - they were around $1800 each new, installed

One benefit of the synthetic 5W-40 HDEO was that it was always near its new viscosity (critically at 40C for diesels) even after up to 130kkms (longest OCI). The average top up rate for all engines was an almost linear rate of 1 ltr/6000kms - the mid point (Min-Max)on the dipstick was my operational level. Drivers were not allowed to fill past that point - oil burn quickly reduced it to the midpoint - a great waste of a valuabel and costly resource. Nearing the end of an OCI the Drivers were not allowed to add lubricant but to let the dipstick level go down to the Min mark - about 8 ltrs from the Max level. Oil temp averaged around 100C IIRC

 

[Steve S]

Also consider the diesel engines I have changed oil on oil Detroits , Cummins take around 12 to 15 gallons with filters and the over the road trucks do 10,000 miles per month + and the overhaul costs which I am sure has risen greatly over the years will benefit dollar wise by a bypass filter of any sort.If I ever owned a big diesel engine it would have bypass filtration with out a second thought. On my P/U trucks "2 Toyotas and a Ford Superduty diesel I wouldn't put a bypass filter on it if I got it for free .

 

[pickled]

LOL the eternal top up will definitely happen if you don't specify to leave the dipstick alone until an action level is reached. We have found that Detroit series 60 and Cummins N14, ISM and ISX engines have a sweet spot, and you almost have to find it for each vehicle due to the subtle variation that exists in tolerances, airflows, etc.. Over the course of a year at one of my client sites we mapped out 10 power units on oil consumption rates per 5,000 miles as a response variable and performed a random cold top up at 6 different standardized zones on the dip sticks (we etched each dipstick with these target markings). What we found is that every one of the vehicles had an optimal crank case fill level where oil would no longer disappear at high rates. It was a very value added exercise with an expensive synthetic lubricant, but I will never forget how repeatable the results were.

 

[dnewton3]

Tee-Dub
The unit of measure on the Y-axis is "wear metal ppm", and the scale is in numeric magnitude. The X-axis is duration of exposure, expressed as miles (5k, 10k, etc). The "average wear" is stated as "units". It's just a word coined from engineering speak. It is a generic term acceptable to reference the area under the curve, rather than call it "wear metal ppm - thousand miles". Sorry, but I didnt' want to type that out each and every time. But the term has NO bearing on the the math or the concept. The "total area under the curve" is represented geometrically by the shaded yellow area, and that "amount" of area is identical in each graph. Do the math; it's EXACTLY equal. If I had to do it over again, I would called it "total average units"; I can see how you're confused by the "terminolgy", but I've more than fully described the actual intent several times now. The amount of wear experienced by the equipment is expressed as "units", and it's magnitude is accurately stated at a magnitude of "180".

On the second question, you're presuming that "T=0" is the beginning of equipment life, but that is NOT a fair assumption. T=0 is the beginning of the test cycle. Just because the test started at "0" doesn't mean the equipment started at "0"; the engine/tranny/etc could have already been in use. Besides, as long as the two graphs start identically, which IS a fair assumption (and one of the preconditions I stated), then it's absolutely correct. Actually, the math to calculate the "area under the curve" would have been a tad simpler by not including the "residual" oil, but then I suspected that the A/R BITOGERS would have blasted me for "ignoring" reality that at least SOME portion of oil never gets fully drained. Seems like I can't win either way.

The reality is that I expected some to nit-pick. I wanted to share a simple concept that would dispell the myths concerning "synthetic" fluids and super-fine filtration. There is no flaw in the math, not the concept. It is a therom used often in engineering to develop life cycle event predictionss for all kinds of scenarios. It can be applied to petro-chemicals, cleansers, blood plasma, re-cycled hydration fluids, mechanical equipment, biodegradeable regenerative decomposition, and blah blah blah.

Synthetics and bypass filtration make fluids last longer, not equipment.

 

[Steve S]

Could we say that the intended operation/service of the vehicle would be the best way to decide the kind of lube oil used and the filtertration used. If you do a 3 month 3,000 mile service syn oil and fancy filters would waste money ,I do in some circumstances this kind if service is good for people who would never check the fliuds, air the tires etc. to the opposite end of the commercial or long distance commuter or in sales who puts on the miles who would benefit financially by running syn oil and fancy filters to extend service life of the oil and its other benefits.

 

[Gary Allan]

The concept is 100% sensible in terms of sensible economies of scale. Not everyone can operate in sensible economies of scale. Commercial/industrial equipment has been spec'd for a certain target life span that is carefully engineered into the whole mix. It's then refitted and put back into service. If there was a way to elongate the refit time with a magic oil or magic device, it really wouldn't matter what it cost as long as it paid for itself in utility in "earning potential" or avoided costs in extended time in service. In all those things (mostly) the chassis/fuselage/housing is either durable or incidental to that piece of equipment's lifespan. The boiler is retubed/re-mudded with refractory material, the aircraft gets a new turbine or avionics, the tractor gets an engine/trans overhaul, the blower gets new bearings. They're already made for continuous operation for a very long time with mandated predictable fatigue times/pauses for refit. Assuming the OEM had good engineers and the salesman sold you what you need, and the owner does what he's supposed to, everything works out to the projected ROI. Very simple concept.

Once you're outside of this "absolute value" environment, then things aren't so clean cut. We've got "cultural" chassis life span criteria that belies sensible economics of scale and we rarely buy with the notion of fitting the need.

There you can be, quite literally, getting into "waste management"

 

[TeeDub]

I will try to explain this one last time, then I give up. Parts per million is NOT a wear rate, it the total amount of wear generated over a particular OCI. Now if you plotted ppm/mile (ie, the wear rate), on the Y axis and miles on the X axis, the area under THAT plot would be the cumulative # of wear.

Go back and look at those two plots and you'll see where you made your mistake....

 

[Steve S]

I spent 23 years working on and with commercial fleet stuff .It usually is made to last and proper care usually is done to get the longest life and or lowest cost per mile or hour etc. The best companies have the cost down to the penny it is amazing to look at the numbers. Some companies turn the equipment over some rebuild and repair which ever works out best for their bottom line ,I can't quite get the grasp on the whole idea but it works for their busisness plan.

 

[Doug Hillary]

Hi,
Steve S - Yes, and it worked for me and for my Customers - it is all about cost effective management. My costs were always done to the 4th decimal point once PCs came on stream - of course the multiplier is millions of kms (or miles)