Cutting open Oil Filters

Ironflight · #1 11-24-2005, 10:54 AM

Despite that fact that I've owned airplanes for a few decades, I have never before been blessed with an engine that had a spin-on filter (always just had screens), so I have no experience with the things...

I'm wondering how many folks actually cut open their filters every time to look for bits and pieces of their engine. A friend gave me a filter cutter, and I opened up my first two filters this morning (I had saved them cause I was curious to cut them open), just to see how it went. A little messy, but didn't find any chunks.

Oh yeah - which way does the flow work on these thigns - from the outside of the paper in - or from the center out? I looked at both sides of the paper, and didn't find any particles....just curious!

Paul

rv8ch · #2 11-24-2005, 10:57 AM

The flow should be outside in. I think cutting them open and having a look is a great idea, but I would also recommend getting regular oil analysis. Now's the time to establish the baseline for potential future problems.

Some good info here: http://www.cancutter.com/

dan · #3 11-29-2005, 03:29 PM

Paul,

I cut my oil filter open and inspect the element every time I do a filter change. There is no good reason not to imho.

As Allen mentioned, I check my screen every 200 hours or 6 months or so. I probably should check it more often, but that's my data point fwiw.

I did oil analysis often at first, but I've scaled back to doing it every 100-150 hours now.

For everybody's info, there is currently a great money-saving special on AOA Oil Analysis Kits. I believe it's only going for one more day:

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Mention the AOPA discount!

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3319 W. EARLL DRIVE
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)_( Dan
RV-7 N714D (708 hours)
http://www.rvproject.com

avpro56 · #4 11-29-2005, 09:03 PM

Paul:

Yes, it's a good idea to cut open your oil filter. Cancutter.com has a cutter that will do it in one turn. A sheetrock knife will work well to slice away the filter element.

Once you have removed the filter element, cut it into two pieces of equal length. Fold them back up and place them in a shop vise with clean jaws. Squeeze until all oil comes away from the paper element, using either a rag or paper towels to soak up the oil being forced from the element. You'll be amazed how much oil you get out of the paper.

When you remove the paper element from the vise, any metal particles will show up very plainly in the light. Try it, it works very well.

Oil analysis is important too; I use Blackstone labs because I like the thorough e-mailed report with a technician's comments. But even that cannot detect a bad cam or lifter in a lycoming. The best way to inspect for a bad cam or lifter is to place the filter element in a jar (after you squeeze it in a vise) with stoddard solvent in it. Shake the jar for a while, rinsing the paper element thoroughly. Remove the element and use your shop pickup magnet (usually a round magnet about 1/2" in diameter) and drag it through the solvent and sediment. Look at the face of the magnet when you remove it from the solvent. You'll see tiny bits of steel on the face of the magnet. A few bits is OK, more than 1/2 of the magnet face covered means you've got cam or lifter trouble. The idea here is that the steel particles are too big to show up in the oil analysis, and the filter has caught them.

At Oshkosh I heard the Lycoming rep say that when he walks into any engine shop he always looks in the trash for uncut used oil filters. He says if he finds them he knows what kind of shop he just walked into.

Anyway, my .02c

Jon Ross
RV-8 N207RV
ATP, A&P IA

mark manda · #5 12-08-2005, 12:20 AM

I don't think there is a reason to cut open a filter on a brand new engine though.

Allen Barrett · #6 12-08-2005, 08:35 AM

There is every reason to cut a filter on a new engine. Just because the engine is new does not mean the potential for problems doesn't exist. What makes a new engine is new parts. Quality of the engine build and parts manufacture defects that are not caught in Q/C determines if the engine will have problems or not. It is common to see flakes of metal in a new or freshly overhauled engine and for a bit afterwards until the engines "sets".

Allen Barrett

mark manda · #7 12-08-2005, 08:56 AM

thanks allen. I was thinking about it and was thinking with all the new grit and material floating around it would just make you sick with worry. Nevertheless, like you said....

how about, no need to do oil analysis on a brand new factory motor? Same reason.

Allen Barrett · #8 12-08-2005, 10:05 AM

Doesn't matter who builds the engine, there is always an opportunity for something just waiting to happen. Quality control both with manufacturing and assembly is paramount to any successful engine build. We're talking about mechanical machines here, and as everyone knows all mechanical things break. However, these two areas alone go a long way in determining the life of the engine.

But, there are things we can do to prolong the life of the engine as well. Regular oil changes (oil is the cheapest maintenance item on an airplane, except a bath). I like 25 hour changes and know of guys that change more often than that! Regular maintenance beyond the normal 50-100 and annual inspections. Corrosion from inactivity is another area. Get a wrench in your hand and check some fasteners once in awhile. In other words, treat it like a good woman, be nice to it, kiss it on the spinner once in awhile and it will give you years of enjoyment. Mistreat it and ignore it, and there will be you know what to pay!!

Allen Barrett

Allen Barrett · #9 12-08-2005, 10:14 AM

Oil analysis. I recommend every 50 hours starting at 50. And be religous about it. It's normal to see some high copper content as well as a bit high iron in the beginning as the engine is breaking in. What we have trended (non-scientifically and with a few exceptions,ie race engines) is that an engine will generally have a problem in it's first 100 or last 100 hours of operation. IF, IF the engine is maintained and used.

Allen Barrett

jimpleasants · #10 12-08-2005, 04:07 PM

I'm not convinced of the utility of oil filters, cutting open oil filters, or spectrographic analysis. By the time something really bad makes an appearance, it's too late for any of these to matter. By examining the screen, it is easy to determine whether the particles are magnetic, or copper, or whatever. If they are big enough, you might even get a part number off one. YMMV