Microns. What's most damage inducing?

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Every time I've looked at that study, I've noticed that the diesel engine filters go down to 7 microns, while the gas engine filters only filter down to 98% efficiency at 15 microns. It also appears that wear reduction for the gas engine flattens out around 25-15 microns (in face, the 25 micron filter has less wear on the upper main than the 15 micron filter). But for the diesel engine, wear is reduced down to the 8.5-7 micron level.

Are diesel engines more vulnerable than gas engines are, to smaller particles? Or was this just these two particular engines studied? Or am I missing something here?
 
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Originally Posted By: paulri
Every time I've looked at that study, I've noticed that the diesel engine filters go down to 7 microns, while the gas engine filters only filter down to 98% efficiency at 15 microns. It also appears that wear reduction for the gas engine flattens out around 25-15 microns (in face, the 25 micron filter has less wear on the upper main than the 15 micron filter). But for the diesel engine, wear is reduced down to the 8.5-7 micron level.

Are diesel engines more vulnerable than gas engines are, to smaller particles? Or was this just these two particular engines studied? Or am I missing something here?

At what efficiency? I'm willing to speculate that all filters will filter "down to 7 microns" including the gas engine one you mention. Something like this:

particle_size_microns.gif
 
All of those micron numbers are at 98% efficiency.

Originally Posted By: kschachn

At what efficiency? I'm willing to speculate that all filters will filter "down to 7 microns" including the gas engine one you mention. Something like this:
 
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Originally Posted By: paulri
All of those micron numbers are at 98% efficiency.

Ahha you mean like the Donaldson or Cummins ones that are available. Sorry, I was thinking of typical spin-on filters for diesel engines, not those. I see now.
 
Originally Posted By: kschachn
I'm willing to speculate that all filters will filter "down to 7 microns" including the gas engine one you mention. Something like this:

particle_size_microns.gif



But it's the efficiency at each micron level that counts. The filters in the upper LH corner are much better at filtering than the others on the chart.
 
Originally Posted By: RamFan
This is the only actual study I could find, given it's age though I was curious if perhaps there was a recent study done. Not that I expect it to change much. It would be interesting to see though if perhaps with the increased oil technology, the filters efficiency is less of a factor.


This one isn't much newer (1990), but what's interesting is they tested filters in the lab to determine their efficiency (similar to an ISO 4548-12 test), then did field testing. Same conclusion, as quoted in the summary statement:

"Corresponding decreases in engine wear metals accompanied reductions in particle concentrations. Results from previous laboratory studies are supported; engine wear is reduced through the use of filters with higher efficiencies at smaller particle sizes."

https://www.sae.org/publications/technical-papers/content/902238/

I will throw in from my own perspective that the longer your OCI is, the more efficient the oil filter should be. If you dump your oil every 3K~5K miles then a less efficient filter will probably give about the same protection from wear as a high efficiency filter used in a 10K+ OCI. It's all about the cumulative number and sizes of particles going 'round and round' inside the engine.
 
Originally Posted By: newtoncd8
Originally Posted By: RamFan
I started looking into this because I noticed a decent amount of variance among filter manufacturers and their efficiency (not nominal) ratings. I'll use the following as an example as they all have a similar price point.

PureOne 14612 ($5.75) - 99.9% @ 40um ISO 4548-12
EcoGard S4612 ($5.31) - 99.9% @ 30um ISO 4548-12
Fram TG6607($6.69) - 99% @ >20um ISO 4548-12 based on average of TG8A, 3387A, & 4967


To add to the list:
Honda A02 - 65% @20um
Toyota OEM - 50% @20um
Wix - 99% @ 23um
Wix XP - 99% @ 35um

In for the discussion as I usually use OEM filters.


Add to that, Hyundai/KIA's very well constructed filter but with avg efficiency...

 
This came up in a few parallel threads last year.

https://bobistheoilguy.com/forums/ubbthreads.php/topics/4596705/Particle_Size_Question#Post4596705

https://bobistheoilguy.com/forums/ubbthreads.php/topics/4598686/Particulate_Size#Post4598686

Some related info in this thread,page 6 onwards https://bobistheoilguy.com/forums/ubbthreads.php/topics/4585323/1

Shannow posted a good overview paper for diesel engines.

http://infohouse.p2ric.org/ref/31/30453.pdf

My Summary :The bulk of the wear is caused by particles below 10 microns. Since there are situations (cam lobes, gears) where the parts are in boundary lubrication with zero separation, there is no particle size too small to cause wear.


diesel-engine-lubrication-and-lube-oil-contamination-control-31-638.jpg


https://image.slidesharecdn.com/dieselen...trol-31-638.jpg
 
Originally Posted By: paulri
Every time I've looked at that study, I've noticed that the diesel engine filters go down to 7 microns, while the gas engine filters only filter down to 98% efficiency at 15 microns. It also appears that wear reduction for the gas engine flattens out around 25-15 microns (in face, the 25 micron filter has less wear on the upper main than the 15 micron filter). But for the diesel engine, wear is reduced down to the 8.5-7 micron level.

Are diesel engines more vulnerable than gas engines are, to smaller particles? Or was this just these two particular engines studied? Or am I missing something here?


Soot?
 
Originally Posted By: goodtimes
That filter (g) did well, being rated @25 microns. Interesting, because Amsoil then goes on to the multi pass test and theirs is 98.7%@15, they say. But the other test was single pass efficiency. I wonder what filter (g), (c), and (d) were.


I saw that as well. It's a sleeper filter. Wonder which one it was.
 
Originally Posted By: shanneba

SAE Testing
In the 1988 Correlating Lube Oil Filtration Efficiencies
With Engine Wear technical paper published
by the Society of Automotive Engineers
(SAE), the relationship between filtration levels
and abrasive engine wear was established. Testing
determined that wear was reduced by as much as
70 percent by switching from a 40µ filter to a 15µ
filter.
The SAE conducted tests on a heavy-duty diesel
engine and an automotive gasoline engine, and
both provided consistent results.



Here is an informative link on filters -
https://www.amsoil.com/techservicesbulle...gine%20Wear.pdf



Thanks for posting shanneba. To play devil's advocate, technological advancement in engines has exponentially changed since 1988. But, the article (if true) makes a point about wear rates. Who knows with all the propaganda? I still believe in preventive maintenance. I like to use a premium filter for my vehicle. Vehicles are not investment, but just a means of transportation and "status bling" for the wealthy.



Respectfully,

Pajero!
 
Originally Posted By: CharlieBauer
Originally Posted By: goodtimes
That filter (g) did well, being rated @25 microns. Interesting, because Amsoil then goes on to the multi pass test and theirs is 98.7%@15, they say. But the other test was single pass efficiency. I wonder what filter (g), (c), and (d) were.


I saw that as well. It's a sleeper filter. Wonder which one it was.


If you look at the table lables, and match those against the graph labels they don't seem to match. For instance, "B & H" in the table (98% @ 15u) doesn't match "B & H" on the graph. Looks like filter G is mismatched also - look where 98% @ 25u is on the graph, way after where the green line G hits the 100% y-axis.
 
Originally Posted By: ZeeOSix
Originally Posted By: CharlieBauer
Originally Posted By: goodtimes
That filter (g) did well, being rated @25 microns. Interesting, because Amsoil then goes on to the multi pass test and theirs is 98.7%@15, they say. But the other test was single pass efficiency. I wonder what filter (g), (c), and (d) were.


I saw that as well. It's a sleeper filter. Wonder which one it was.


If you look at the table lables, and match those against the graph labels they don't seem to match. For instance, "B & H" in the table (98% @ 15u) doesn't match "B & H" on the graph. Looks like filter G is mismatched also - look where 98% @ 25u is on the graph, way after where the green line G hits the 100% y-axis.


B&H should be green.

F should be pink. G should be yellow. Or in those areas.
 
From a 28 million dollar engine wear study
"Abrasive engine wear can be substantially reduced with an increase in filter SPE(MP). Compared to a 40 micron filter, engine wear was reduced by 50% with 30 micron filtration." (98% point) "Likewise, wear was reduced by 70% with 15 micron filtration." (SAE TPS 881825 p5 - David R. Staley, General Motors Corp. 1988)
Particles smaller than 10 microns remain suspended in the oil with little to no harm to engine bearings. 10-20 micron particles are the most damaging.
 
Originally Posted By: Motorking
From a 28 million dollar engine wear study
"Abrasive engine wear can be substantially reduced with an increase in filter SPE(MP). Compared to a 40 micron filter, engine wear was reduced by 50% with 30 micron filtration." (98% point) "Likewise, wear was reduced by 70% with 15 micron filtration." (SAE TPS 881825 p5 - David R. Staley, General Motors Corp. 1988)
Particles smaller than 10 microns remain suspended in the oil with little to no harm to engine bearings. 10-20 micron particles are the most damaging.


Is your last line "Particles smaller than 10 microns remain suspended in the oil with little to no harm to engine bearings. 10-20 micron particles are the most damaging." a quote from that study, or your own editorial?

I ask because its at odds with the study I posted, though thats diesels. It also refers specifically to engine bearings, which arent the only wear point in the engine and aren't those most likely to be affected by small particles.

Perhaps the literature is inconsistent on this question.
 
Originally Posted By: Motorking

Particles smaller than 10 microns remain suspended in the oil with little to no harm to engine bearings. 10-20 micron particles are the most damaging.


I don't have ready access to that much-quoted paper (as for most SAE papers), but I did find a .pdf which allegedly quotes from its conclusions, and includes the line

"Controlling the abrasive contaminants in the range of 2 to 22 Microns in the lube oil is necessary for controlling Engine wear."

http://www.shopfiltermag.com/wp-content/uploads/2015/01/Summary_SAE_FilterMAG1.pdf

The phrase "lube oil" makes me suspect this is not, however, a direct quote, and the source clearly has an agenda.
 
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