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Dummies Guide to Oil Screen?

RBD

Well Known Member
I plan on changing my oil and filter tomorrow, and figure that I need to also pull the screen on my O-360. Problem is, I don't where the little guy lives, and I'm not afraid to admit it! I Googled the topic for a few minutes (and searched this site,) but couldn't find what I was looking for. If anyone has a picture and/or some tips (I did read that the screens can be tricky to reinstall properly) please pass them along.

Many thanks!
 
You will need a crush washer. Check your manual for the correct one. Manual is also a good place to find the location.
 
Ryan....

....it is located just about in the center of the rear of the oil sump, down low...yes, you can't reach it hardly:)...and it's safetied, usually.

We usually check ours at annual/condition inspection time and usually get bits of carbon from it.

Best,
 
Oh, oh!. I've checked the screen again just last Saturday, over four hundred hrs now. I don't recall a crush washer under the screen plug. Mine I would say is just a brass type flat washer. It's a Mattituck 360, is this posible that I have a reusable washer?
I also noticed a little carbon in it for the first time.
 
My guess would be that what you are thinking is a "flat washer" is really a "crushed" crush washer. supostabe a crush washer.
 
OIL SCREEN(S)

If you have an oil filter you have one screen in the sump. This screen is the one with the crush washer and safety wire. If you DON'T have an oil filter, you have a screen located centrally on the accessory housing. This screen housing is held in place by four 1/4" cap screws/and or studs with lock washers. Remove the screws/nuts, pull the housing aft, and the screen will slide out the forward end of the housing. use new lock washers and a new gasket. Install the gasket dry, make sure the gasket and the housing are oriented properly with regard to the oil passage holes. If you have a steam gage for oil temp you COULD have a crush washer on the oil temp probe which screws into the aft end of the housing. More likely you have an electrical connection, or a steam gage probe that does not require a crush washer.
 
We always check/clean the screen with Oil changes. Apart from anything else, in a taildragger it allows you to drain more oil from the engine.

We also know you are supposed to use a new washer each time... but have yet to get around to getting some :eek: So put that under "best practice" but not end of world if you use the old one (worst I can see happening is a slight leak?).

Andy
 
If you have a solid copper gasket you can reuse it by annealing it with a propane torch until it changed color. It will look kinda like a rainbow, then let it aircool. Soft & good as new. Worked for me anyway.
 
Done

Getting a socket on the 5/8ths head wasn't too bad, but man was the safety wire a pain the butt. I did find a fair amount of shiney flakes and carbon bits, but the local airport mechanic said it's nothing abnormal. What do you guys think? I have no idea when the last time this screen was checked/cleaned.

IMG_0422.JPG

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confusion

Lets not get confused. Depending on the engine, there could be two oil screens. Usually you find one on the side of the oil pan with a crush gasket... you will need to replace it. Also depending on the model, on the rear of the engine, there could be one. I have plenty of pics if you need them. It depends if there is an oil filter or not. I'm always available for questions if you have any. Feel free to PM me.
Best
Brian Wallis
 
Thanks Brian. It's an 0-360 A1D, and I do have an oil filter. I pulled the screen from the rear of the sump.

Are my little metal friends "normal"? They are paper thin, and as you can see (when comparing them to my finger) pretty small.
 
screen findings

Lycoming has a publication called Key Reprints that costs nothing more than a phone call if you own an engine. The first oil change on an engine will usually turn up a fair amount of stuff, after that, it depends on what kind of metal (ferrous dark, ferrous shiny, aluminum, brass flakes or dust) I allways give the prop a good shove aft and then forward to make sure there is a clearance durring preflight. If that clearance goes away, check your screens and filter (or high pressure screen) right away. That clearance is probably filled with metal. I also cut open filters and check screens every oil change.

Andrew
A&P I.A.
 
Ryan - I check that screen on my 2200 hour O-235 at every change and I've never seen anything in it like that. Usually I get nothing, or maybe a chunk of carbon type stuff. Since your mechanic said its OK, I wouldn't worry about what you've found

Of course, those flakes could have been in there a really long time if that screen hasn't been pulled. The best thing might be to check it again in 25 hours.
 
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Crush Gasket Size?

Does any one know the size of the AN900 crush gasket for the oil screen plug on on a Lycoming O360-A1A?

Ordering a handful from Spruce but don't know the diameter or dash number. Can't find in manual.

Thanks

Jim Sharkey
 
Does any one know the size of the AN900 crush gasket for the oil screen plug on on a Lycoming O360-A1A?

Ordering a handful from Spruce but don't know the diameter or dash number. Can't find in manual.

Thanks

Jim Sharkey

Found it in PC-306-1B, the Parts Catalog for O-360-A Wide Cylinder Flange Engines.

Lycoming p/n is STD-111 with an I/D of 1" so it's an AN900-16.

And for some strange reason the MS part number is a -21. Go figure.

Jim Sharkey
 
IO-540

I know this is an old thread. Is the crush gasket for the oil screen the same for the different Lycoming engines? I've got an IO-540 D4A5 in my RV10. Is AN960-16 the right size?
 
I know this is an old thread. Is the crush gasket for the oil screen the same for the different Lycoming engines? I've got an IO-540 D4A5 in my RV10. Is AN960-16 the right size?

No. AN960 is a solid washer. AN900 is a crush gasket with an asbestos insert.

Fiber material goes against the non-tightening part, tightened 135 degrees past hand tight. Check the Direct Drive Overhaul Manual for details.
 
No. AN960 is a solid washer. AN900 is a crush gasket with an asbestos insert.

Thank you very much. My bad. That was a typo on my part. .... Is the AN900-16 the crush gasket needed for the IO-540? I've looked through multiple documents and found the procedure for changing the screen but I can't find any part numbers for the gasket(s).
 
Yes that's the one - AN900-16, also called MS35769-21, 44 cents ea at Spruce. FWIW the Lycoming part is 07-03129 but it's spendier. I ordered both the first time just to confirm they were the same. I always get a few at a time to have at least one extra on hand, along with a big bag of spark plug washers.

==dave==
N102FM
 
Thank you very much. My bad. That was a typo on my part. .... Is the AN900-16 the crush gasket needed for the IO-540? I've looked through multiple documents and found the procedure for changing the screen but I can't find any part numbers for the gasket(s).

You can reuse that crush washer (and the ones for the spark plugs too) if you want, just anneal them. Heat it with a propane torch until it glows. I hold it over the flame with a piece of safety wire. Then quench it in a cup of water. It will be bright, shiny, and most importantly soft/flexible once again.
 
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You can reuse that crush washer (and the ones for the spark plugs too) if you want, just anneal them. Heat it with a propane torch until it glows. I hold it over the flame with a piece of safety wire. Then quench it in a cup of water. It will be bright, shiny, and most importantly soft/flexible once again.

AN900-16 $0.44
 

So? I didn't point the procedure out as a cost savings--I've bought new ones myself. I did it to point out you don't have to buy a new one if you don't want to or if time is of the essence. It takes less than a minute to anneal a washer back to a like new condition vs 3-5 days ship time for the mail, if you didn't have the foresight to buy one ahead of time.
 
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I didn't offer this advice as a cost savings. I did it to point out you don't have to buy a new one if you don't want to or if time is of the essence. It takes less than a minute to anneal a washer back to a like new condition vs 3-5 days ship time for the mail, if you didn't have the foresight to buy one ahead of time.

I do reuse solid copper gaskets by annealing them but I personally don't do it with crush washers that have the inserts in them.
 
I do reuse solid copper gaskets by annealing them but I personally don't do it with crush washers that have the inserts in them.

I'm talking about plain cooper washers only -- AN900 and AN4027s. Can't speak to other types, especially with inserts.
 
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