The International Cessna^® 170 Association

Like most of you guys I like to tinker and build things. Does anyone have plans for an oil filter cutter they would like to share? I think $60 bucks is way too high for something that simple. I've seen a set of plans before but cannot locate them again. A buddy of mine bought one and if I have to reverse engineer one thats okay, but I thought I'd try the experts first. Any help would be appreciated.

I built my own but don't have plans. Here are pictures:





When we build these things we try to use what we got. The bearings we had which determined the size of the bolts used to hold them otherwise we'd have used smaller ones. You may not have to stack the bearings as we did but we had em and it holds the filter nice an square.

The bar stock we had. It's about 1/4 by 1-1/4. the cutting wheel is a normal pipe cutting wheel available for about $4 at Ace Hardware and is the only part we bought.

Since the photos where taken we've drilled a 7/8" hole in the middle of the bar under the center where the filter sits to accommodate filters with nipples.

Special Note: The pictures where captioned for another pilots group I belong to. We got to calling anything made or work done for our airplanes as being done by "The Skunkworks". We've since changed that name to "Stinkworks" to avoid a lawsuit from Lockheed Martin and the name is probably better suited for the work done anyway.

Bruce,
Thank you very much. Fabrication will begin this week in my hangar. I knew somebody from the 170 association would have it figured out. Thanks again,
Paul

a dumb Q
what are they for?
dave

iowa wrote:a dumb Q
what are they for?
dave

They are used to cut open your used oil filter to see what part numbers fall out.

LowNslow must refer to your plane.....certainly not your wit.......

Not a dumb question if you have the original oil screen, Dave! Russ Farris

iowa

Many aircraft engines have oil filters instead of screens. The Continentals in our 170s would have screens but many of us have changed to a filter system.

It any case since we don't have a screen to check for metal (the filter replaced it) the only way to check is to open the filter. You must have an opener of some type to do this. A hacksaw won't work because you'd be filling the filter with metal from the filter can from the opening process.

I can remember my first airplane way back was a Cherokee and it didn't have a filter but most do these days. I to was a bit surprised the first time someone asked if I cut open my filters. Of course I played along like I was an old pro at filter cutting and inspection.

Cutting filters open will probably show if something major is wrong with the engine. If the metal in the filter is big enough to see with the naked eye, it may be too late to save the engine, but will probably save your bacon.

Oil sampling and sending it in for analysis is a better way to check engine condition. Consistent oil sampling establishes a trend over time. Any significant change in the trend may show a change in engine condition.

I am not trying to down play the value of cutting filters open, but oil analysis by a lab will detect particles the human eye will miss and establishes a trend.

Bill

I certainly don't mean to deny that a good analysis program isn't interesting, and maybe a few cases exist where someone offered a testimonial in which it predicted catastrophic failure a few hours down the road. But I consider it overkill. (Another case of measuring with a micrometer something we intend to cut with an oil-filter opener.)
Analysis programs were introduced in the late fifty's/early sixties when turbine engines were so expensive and out-of-reach of even corporate operators, that turbine/jet engine mfr's offered on-going warranty programs like power-by-the-hour/MSP/etc. Corporations were so afraid of the expensive prospect of a sudden failure of their expensive new jets they would frequently avoid the issue by staying with old WW-II converted airplanes like Lockheed Lodestars/Howard 500's, etc. rather than run the risk of losing an engine that cost more than an entire airplane.
Oil analysis was a method of catching a failing bearing before it shelled out the entire core of a turbine. (And this was when synthetic turbine oils were marketed by individuals and independent laboratories under trade names which would never be recognized today.) Times have changed.
In any case, checking the screens/filters at every oil change for foreign materials is a good way to discover if something is breaking down inside the engine. The most common discovery is carbon particles (usually from beneath piston domes where engine oil has been scorched due to heat, then fallen off and circulated to the screen/filter.) Occasionally a copper/bronze/brass particle is found (also unlikely to be significant.)
When larger pieces of copper, aluminum, or ferrous material of any visible size is found, then it's time to investigate further. The low-stress level of our engines is not likely to surprise us with sudden stoppage without some indication in the screen/filter unless it's an ignition or fuel delivery problem. And in any case, a sudden failure in either ignition or fuel delivery is not something one can ordinarily expect oil analysis to predict.)
There are so many ways that most owners mis-manage oil analysis programs that end up in needless additional costs chasing non-problems that I don't recommend them to the average owner. (One area that oil analysis does operate well is detection of induction-system leaks. Silicon (dirt) increases is easily detected with analysis. But so is regular physical inspection of the system, which we should all be doing anyway.)
This is not to say that analysis isn't interesting and fun, if you're the type to enjoy such details. I just don't believe it's worth the expense and trouble for the average owner. It's much more useful for the fleet operator who practices stringent sample-control and operating practices in commercial operations, particularly with turbine equipment. IMHO

I am not suggesting that cutting filters and inspecting the contents does not have value or that anyone should start a fluid analysis program.

I do believe that long term fluid analysis that sets a trend in oil and engine condition can detect metals and a possible engine problem before the human eye can see it on a paper filter element.

Bill

is this s.t. that the mechanics
routinely do at annual?
iowa

When your oil is changed whether that be at annual or any other time you should remove and check you screens or replace your filter which ever you have. When the filter is replaced that is when you would want to cut it and check it.

I take it you don't do your own oil changes in your airplane Dave. That's Ok if you don't I would just find it odd someone with your other mechanical hobbies (Jeeps and such) pay someone do their oil change.

how many hours before it should be changed?
dave

You will probably get a lot of different opinions, but I change my oil and filter every 25 hours or 3- 4 months whichever come first. If I have not been flying allot and have less than 15 or so hours on the filter I may just change the oil and skip the filter. I cut the filter at every filter change. I use The Airwolf cutter and am quite happy with it, but they are getting a bit pricey now. There are many others available.