I just got my Blackstone labs oil report back and among what they said in the verbage was "The AIR & OIL filters are working well too"
This is with 5k miles on Shell Rotella synthetic with a PUROLATOR PURE ONE OIL & AIR filter: I was already a big fan of Purolator's PURE ONE line, I am using just the drop in replacement panel filter in the stock air box on my 99.5, so I guess by this I have no dust/dirt getting by the filter, it has about 15k miles on it, and I plan on changing it when it gets to 20k- the PURE ONE filters are more expensive that standard ones from Purolator or Motorcraft for that matter but then these 7.3s are expensive to replace too!!

 

I have used the Pure One filter in various vehicles before and always had good luck with them. Congrats on the good report.

 

The only problem I guess is that they don't make a PURE ONE for the earlybird 99s, thats how I found out that mine is a 99.5
Blackstone said I had a great wearing engine, and that I could easily go 6k or even 7.5k miles on the next oil change, so I'm going to do the 7.5 and send in anouther sample & see where I am then.

 

On my truck I can go to about 10k miles on rotella synthetic, and they still say the oil is ok, but should be changed. I did two analasys' at the 7500 mark, and everything was still well below average. You may go to about 8k next oil change if everything looks good now at 5k.

 

I agree with your strategy of not being "penny wise and pound foolish" when it comes to protecting your engine but the ability of an air filter to protect your engine is measured in accordance with testing procedure ISO-5011 to determine its "Dirt Filtering Efficiency" not with a UOA report which as I'll discuss can't really say very much at all about how well your air filter is performing!

The PURE ONE filters might very well have a "Dirt Filtering Efficiency" that's as good as or even better than the ISO-5011 tested 99.76% "Dirt Filtering Efficiency" of a "genuine" Motorcraft FA-1750 (Ford P/N 2U2Z-9601-AA) filter but I can't find any evidence that the "Dirt Filtering Efficiency" of PURE ONE filters has been tested using the ISO-5011 procedure or for that matter that they've been tested at all using any procedure!

With the stock 99.5 air box you need to be vigilant in maintaining a good air tight seal around the perimeter of the lid. On my old early 99 F350 I used to apply some petroleum jelly around the perimeter of the lid to help ensure a good seal but over the years Ford has continuously updated and improved their stock filter element so this precaution is probably an overkill today.

In 2002 Ford specified the FA-1680 element for the 7.3L F-350 and then later this was updated to the FA-1720 element which has filter pleats about double the depth of the previous FA-1680 element and then additional improvements to the element's perimeter seal resulted in the latest FA-1750 element.

Any third party vendor can claim that their element is an exact replacement for or even a better version of the latest FA-1750 element but as far as I can tell there's no testing data to back up these claims!

The surface of the FA-1750 element shown below has a kind of "waxy" feel and this distinguishing feature as compared to a plain dry white paper element is important for improved "Dirt Filtering Efficiency" of "invisible" particulate matter with very small um diameters. Also note the thickness and width of the perimeter seal which is a feature that might not be exactly duplicated in a third party replacement version.



Of course everyone wants to have an acceptable UOA report because the alternative means that something is seriously wrong but lets think through the logic steps of how a given UOA report might possibly confirm if an air filter is performing as it should.

A given UOA report is based on an oil sample plus the miles traveled and how many replacement quarts of oil were added during those miles and that we started with new oil and a new oil filter.

1) The first big uncertainty is that the UOA lab doesn't know how dusty the environment was during those miles traveled so they'd need to make a guess based on some "standard" dust particle density assumption for a "typical" atmosphere?

2) The second big uncertainty is that as dust passes through the air filter and into the turbo only some of it makes its way through the intercooler and into the cylinders and then only some of that dust makes its way past the piston rings and begins to accumulate in the 4 gallon oil reservoir in the pan. Most of the dust that's ingested by the engine during the intake strokes just goes right back out again during the exhaust strokes!

3) The third big uncertainty is that for each pass of the 4 gallons of oil through the high efficiency oil filter a large but completely unknown percentage of the dust that did make its way past the piston rings gets filtered out by the oil filter and only a small but completely unknown percentage remains in the general 4 gallon oil reservoir a sample of which is what's sent to the UOA lab to be tested!

So considering all of the above uncertainties how can a UOA lab use the ppm Silicon from this oil sample to calculate how much dust passed through the air filter and then compare that amount of dust to how much dust entered the air filter intake because this is what's required in order to evaluate the performance of an air filter!

Silicon makes up about 25% of the earth's crust by weight but in some operating environments such as cities most of the particulate matter in the air isn't Silicon based so in these environments you might even get an acceptable ppm Silicon from an OA report without using any air filter at all!

 

Just kind of an aside on this point, Gene, I think the fl1995 is a 12-15 micron nominal filter, the spectroscopy used in UOA really doesn't account (at least accurately) for particles greater in size than 10 micron, so UOA isn't going to accurately account for anything the oil filter can capture.

 

The FL-1995 is listed as providing a single pass efficiency of 68% for 20 micron particles but it does filter out some % of particles down to 1 micron with each pass.

What's the GPM flow of the LOP? How long does it take for all 4 gal to make one pass through the filter? The net filtration efficiency for small particles less than 20 microns increases with the number of passes so if you drive through a dust storm and then operate in a benign environment for awhile most of the dust ingested from the storm gets cleaned from the oil reserve in the pan and won't show up in a sample.

I used to have some specs which I can't find just now on the Fleetguard LF-3974 (Stratapore) filter which I switched to soon after it was introduced because it provides a higher filtration efficiency of small particles less than 20 microns but still has the same flow restriction of a FL-1995.

I interpret this as agreeing with me that a UOA report doesn't say a whole lot about how well an air filter is performing.

For an ISO-5011 test of air filter performance the "Dirt Filtering Efficiency" is determined from...

"Dirt Filtering Efficiency"={"Dirt Holding Capacity"}/{"Dirt Holding Capacity"+"Dirt Passed"}

...where the "Dirt Holding Capacity" and the "Dirt Passed" are measured according to a standard protocol which involves establishing a constant 628 CFM airflow through an initially clean filter and then introducing into the input airflow stream a controlled amount of "standardized dust" at a controlled Dust Feed Rate of 17.58 grams/min.

When the Inches H2O Restriction increases to 10 Inches above the initial H2O Restriction for a clean filter the Dust Feed is terminated and the results are tabulated. The "Dirt Passed" is collected by a downstream HEPA filter and the "Dirt Holding Capacity" measures the dust stopped by the filter and the "Dirt Filtering Efficiency" represents the percentage of dust that was stopped by the filter during the test.

The "standardized dust" meets an ISO-12103 standard which has a specified distribution of particle diameters ranging from about 0.5 micron to 150 micron and the peak of the particle distribution curve is at a 60 micron particle diameter.

Since about half of the "standardized dust" particles have diameters less than 60 microns they're "invisible" to the naked eye so claiming that a particular air filter is providing a good or even an adequate "Dirt Filtering Efficiency" just because "my intake tube looks clean" isn't any better a criteria than a UOA report is.

For the stock FA-1750 filter the "Dirt Filtering Efficiency"={542.0}/{1.31+542.0}=0.9976=99.76%.

 

I'm not diasgreeing with you, but the remaining question is what size particle will typically get past the rings? Of course it would depend upon the condition of the engine, but I wonder what size particles can get past in a generally good condition engine. Seems like the rings would sort for the smaller particle size.

 

Well 30 microns=0.001" and when that's compared to the typical valve stem to guide clearance of up to 0.003" on the intakes and up to 0.004" on the exhausts I can see where dust that's up to 90 to 120 microns could migrate past the valve stems and get into the oil that way.

The vertical clearance between the ring and the ring land in the piston is up to 0.004" and that's a possible entry path for particles up 120 microns. Then there's the ring gaps to consider which are up to 0.005" and even though they're supposed to be staggered dust can eventually work its way through that path. When you consider the 2,000 psi combustion pressures involved it's not hard to see dusting blowing past these clearances carried along with fuel wash down etc...

The point is how could a UOA lab possibly know to within even an order of magnitude just how much dust is actually entering the oil in a particular customers engine and then how much of that dust stays in the oil and gets sampled and then know how much dust was in the customers environment and going into the air filter intake to begin with? Yet they tell their customers that their air filters are working well?