So I just added a Casper Labs oil fitler kit to my O-320... after 57 years of faithful service I think she deserves it I've been getting oil analysis done every other oil change. Curious if the adition of a filter has any effect on an oil analysis results? My first thought was that the metal particles they look for are very small and would not get trapped in the filter and thus should not change the oil analysis ppm counts much. Does this sound correcT?


20131119_155138 by scottf, on Flickr

I would think it would have to change some. It only makes sense. But the microscopic particles should still pass through for the most part.

Maybe a good time for an experiment.
Let us know your results.

You need to inform the analysis lab that you now have a filter.

Also, you now need to cut open the filter at each oil change interval, remove the media, and carefully was out any particulate from the paper media, capturing that for examination. It's pretty easy to then separate size and type of residue. Magnet will find steel (depending on amount VERY bad), and visual to I'd bronze, aluminum. If you see any particles large enough to read part numbers, you might want to consult an overhauled....

MTV

If you see any particles large enough to read part numbers.....

well I guess I will see how the next results come in probably early next year with my first oil change since the filter has been installed. Got a filter cutter ordered.

I am curious to see if there is any change (i would not think so) but curious anyway. In south texas an oil filter will make an engine run hotter though!

Finally, a topic I actually know something about. I kind of deal with this for a living. It's mostly about particle size versus filtration level, but in general, I would say that a filter will definitely affect the oil analysis. It's a matter of how much. All filters are not the same. They have different ratings with some being so fine that even average wear particles will be filtered out. I've actually recommended in some cases to not bother with oil analysis because if the filtration is fine enough, it doesn't ever have anything but clean oil. That is not the case in your average oil filter though. I would guess that the average old school filtration is on the order of 12 microns with most wear particles being smaller than that. So my guess would be a general reduction in trace elements as a result of adding a filter across the board but with the average filter, it's still worth doing.

Wayne

Where I fly the procedure is;

If we can not see anything in the paper or screens, then the engine will hold until TBO. Lycoming agrees too. There is nowhere in my approved data which shows oil analysis is required or even desired on a 2000 hour TBO engine. My guys recommend saving the money/time for the overhaul and fly often. And these guys have been racking up hours in part 91/135/141 for a long time.

I found in the PDF over at luscombe.org the following quote (I'm using a Champio 48108-1 filter):

The information from Champion’s product manager is this: “Typically, the filter media catches almost 100% of the particles over 40 microns in size. From there, it catches, in diminishing percentages, particles all the way down to about 5 microns in size. It's the particles over 40 microns in size that cause engine damage/wear.“

It'll probably take me a few months but I'll post the before/after results from the lab.

Well first results are in, I tried to keep the engine hours run about the same as before I had the filter instaled (28 hours this last interval with filter, vs. 25 hours w/no filter before that).

minor decrease in aluminum, iron, copper and chromium. not sure that it is a meaningful difference, but interesting none the less.