The International Cessna^® 170 Association

OK, I'm trolling for opinions on putting a magnet or two somewhere around my elephant trap, er, oil screen. Anybody have any experience with this?

I've seen people put them on the outside of their oil filters, to try and wring every last bit of abrasive metal out of the oil that they can. Sacremento Sky Ranch, I think, sells some that they claim to have documentation for. I wouldn't worry about hanging them onto a filter, but I am sadly not equipped with a filter - so, my question.

I'm thinking that I might be able to catch some of the rust etc particles that come off and that the screen will never slow down. I haven't looked to see which way would be better, actually putting one right on the screen (safety wired) or somehow outside? Just an idea that has been rattling around in my spacious, carefree brain.

Hans

Speaking of which, I have seen some sort of magnet arrangements which snap around the spin-on oil filter. Exactly what's the idea with these? Do they magnetically catch particles that are too fine for the filter to catch? Hard to believe-- that cardboard-like filter media seems like it would catch just about anything- even the proverbial angels that can dance on the head of a pin. I always cut my old filter open, cut & peel the media, and look for "evidence"-- never find any.
Anyone use these magnet things, or have any comment on them?

Eric

Seems to me to be a solution without a problem. As Eric said, I would imagine that the filter would catch most anything. If your engine is making any serious metal, it would easily show up in the filter and you wouldn't be flying it any more anyway (one would hope). If the particles are small enough to escape the filter they'd have to be so small as to be virtually undetectable. Besides anyone who does consistent oil changes would likely drain the stuff out with oil (if they are using AD oil).

If this were really an issue then I would think that the oil companies would have developed a new "must have" oil or filter for us to "combat" the problem. If there was really money to be made with it they would have found a way by now.

Come on fellas! He just said that he doesn't HAVE a filter, He's looking to trap the stuff at the screen housing.

Instead of monkeying around with wiring magnets into the screen, etc,-- if you're worried about something getting by the screen I'd just pop for a spin-on adapter. They were running around $300 for the F&M type a few years ago. Filters are $15-20 a shot, but you can extend your oil change intervals which cuts down on oil cost a bit to offset the price of filters.
I believe there's also another filter (Airwolf?) which mounts remotely, like on the firewall. Don't know the cost on those.

Eric

HA,
The oil filter is probably your best bet for metal removal, I agree that anything that passes a filter should be inconsequental.

That being said, a magnet placed "in" the oil screen would useful in removing metal that the screen missed. I would investigate the Sky Ranch magnet installation and if I liked it, give it a try. I think you will probably be suprised how much metal it attracts. Personally, I would want one mounted on the drain plug. My theory, what makes the difference where or how you remove the metal, get it out.

I have used magents for removing metal for years in industrial engines, with filters installed. You would be suprised at the amount of metal they remove. The metal that is attracted is normally in a fine black powder form. Either the filters do not get it all or the magnet gets it first. Who cares, either way it is removed.

Let us know what you decide and how it works. My father used to tell me, get the led out and he wasn't talking about an engine.
Ralph

It's amazing what our imaginations can do in the absence of good technical info. I'm no different than anyone else in this regard.
The typical spin-on oil filter will catch virtually anything larger than 40 microns, and it's generally held that anything smaller than that is too small to cause injury. The oil-film on plain bearings under load is typically about 80 microns, so anything smaller than 1/2 that measurement will float in the film without injuring the engine parts.
The philosopy I personally use to explain my own disregard of that "scientific" information (I believe it was Aviation Consumer who I remember writing about the subject in an article comparing various oil filter brands) ...in other words, the reason I use magnets anyway is because it makes me feel better. When I cut open my oil filters I find large areas of dark dust stuck to the inside walls of the can in exactly the same shape as my magnets. I prefer to have it reside there than in my filter media (I have no idea how to measure individual pieces of the dust) or circulating in my oil....no matter what it's size.
The magnets I use are a cute STC'd gizmo mfr'd by RAM Aircraft Engines of Waco, TX. It consists of a wide, circular, flat, aluminum clamp (similar to a high-pressure air clamp used on turbine aircraft) which has an adjustment screw to close it upon the oil filter can. It holds a series of magnets within it's structure in a ring around the filter. It has a nice engraved/stamped legend on it that says, "FAA-PMA, RAM Aircraft Engines, Inc." I have absolutely no supporting paperwork as I found it lying in the junk pile when I was up at Waco with a customer's airplane being worked on at RAM's recommended Cessna Service Center. The mechanics there had performed an oil change on hundreds of customer airplanes and their typical reaction when confronted with a gizmo installed on a filter was to remove it so they could cut open the filter, and toss it into a large, plastic garbage can over in the corner along with dozens of others of the device. I asked for one, and the closest mechanic shrugged his shoulders and said, "Help yourself." and went about his work.
Mine really catches a surprising amount of metal and holds it inside the filter. Would that stuff hurt my engine if the magnets weren't there? I doubt it.
Will the magnets extend my engine's TBO? No. If my engine makes it to 1800 hours then I'll consider it time for overhaul anyway.
Finally, it's amazing how long these engines last with only those original screens which will pick up anything large enough to have a part number engraved on it.
(Also you might remember a magnet only will hold magnetic/ferrous material. It won't affect all the aluminum, pewter, bronze, chrome, copper, dirt or silicon, carbon, or anything else.)
Even with my magnets I still change my oil AND filter every 25 hours. Even though TCM will approve the oil change interval to be extended up to 100 hours with use of a filter, and even though these filters will hold a lot more dirt/metal than any screen, ...the chronological period of time to change oil for reasons of accumulated condensation, acids, and other corrosive combustion by-products remains at the recommended 3 months. I fly my airplane about 100 hours a year therefore 25-hour oil changes work out about right for me. (But I still enjoy illogically looking at my smudges of black, magnetic dust captured inside the filter can.)
Hans, I'd recommend you spend your first improvement-dollars on an FM Enterprises oil filter adaptor for your airplane.
http://www.fm-enterprises.com/

thanks George, I knew somebody would be using magnets. and I agree that I probably won't catch anything useful, since if the chunks are big enough to worry about then I'll see them in the screen and I won't be extending the life on anything, just looking for the cam lobe or whatever is grinding away. I read a report on these magnets, Aviation Consumer maybe?, and they found pretty much the same as you - black smudge and warm happy feeling. sometimes I just feel strongly that there should really be a hyphen between anal and retentive

I always run a magnet around in the bottom of the oil screen area every time I change oil, just in case something is lurking. I think I am most worried about rust particles and their abrasive qualities, since I really do not fly my plane often enough. If I had a filter I probably wouldn't worry so much. And I think that someday soon I'll probably add a filter, if nothing else to save the delicate accessory housing threads from the constant in and out of the screen.

Hans