| I think you must be comfortable with fuel/oil line security and safety and use accepted procedures for putting those lines in place. The race guys have a better solution for fuel lines than what we currently use but that's a different topic and needs some pictures and references.
Assuming you are okay with another set of lines I would think some factors to consider:
1) Effect of parallel draw--maybe the PSI adjustment needs to go up a small fraction to compensate for another path of oil. 2) effect of cold oil and whether the secondary is protected by the pressure relief system. 3) Is the secondary in the temp control circuit or outside and what might happen if that line freezes up 4) where is the safest place to dump the secondary output and are the connections safe from vibration and other issues 5) how will the secondary element be replaced or cleaned easily 6) Who will do the oil analysis to determine the effectiveness of adding the secondary so the rest of us can look at micron results 7) How to measure volume through the secondary to get some idea of circulation and filtering efficiency.
Overall, it sounds like a great idea but it makes me wonder why existing systems don't have a parallel function built in or why large filters don't already have a dual filtration system within the filter itself.
Paul
Paul,
yes, the secondary filters for autos definitely caught my eye when I was looking at the problem a few years ago.
...but it seems like an area where if you screw it up it's very bad news. the secondary idea SEEMS less risky than a high efficiency element but it requires yet two more lines (I already have 4 for the turbos and 2 for the remote mounted filter) and could conceivably have some odd side effects.
I wonder what kind of a test protocol you would have to set up to feel reasonably confident you had a good installation?
all in all I'm inclined to change my oil at short intervals and hope someone else will figure this out some day. Nevertheless, after doing the Continental factory tour I'm very inclined to believe that clean oil would be a good thing.
Colyn On Jan 16, 2014, at 9:12 AM, Paul Miller wrote: Colyn, I did a small amount of research on this issue and believe that a secondary filter may be worth experimenting with. The concept is to leave the stock oil filter alone. Testing the stock filters and the micron filtration on each of the typical brands is found on the web. Tempest says this about filters:
The average porosity of aviation oil filter media is about 40 microns. There are smaller and larger pores in the media but, on average, the media will catch most of the 40 micron or larger particles. The smaller the particles in the oil, the fewer will be caught by a given media. For example, a 40 micron media may only stop 80% of 30 micron particles, 40% of 20 micron particles, and 10% of 5 micron particles. Steel particles in the oil are often five microns or less, so most will pass through the filter media and circulate, hour after hour, through the engine with the oil.
Some of the race guys and I think all the big diesels use a secondary oil filter for ultra fine particle capture. Perhaps others already know much more about this subject but it appears that installing a small-micron oil filter as a secondary unit fed by a secondary supply source could capture junk that our primary filters are not designed to capture. This leaves the primary circuit intact including bypass, over-pressure relief and so on. One article spoke about using the existing oil pressure transmission line as the source of oil to a secondary filter and directing the output to the oil pan, rocker cover or possibly the oil filler tube. Even at the smaller line size for this smaller filter, the oil would be passed through at least once a few times each hour, says the calculation. Searching reveals a number of fine micron filters (cleanable and replaceable) that are available in stainless and anodized high pressure cannisters that would easily fit on a firewall and apparently can capture debris in the 2-10 micron range. Prices are all over the map.
It sounds like it could be done for a reasonable price plus hoses and connection fittings if someone thought it was worth testing.
Paul IO550
I could get excited about better air filter efficiency if I could buy an efficient oil filter for my aircraft engine.
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