Is the oil screen really necessary?

pboyce · #1 01-28-2006, 08:26 PM

A very experienced A&P at my field, whose judgement I respect, strongly suggested that since I have an oil filter on my 180hp Superior engine, the oil screen was completely uneccesary. In fact, he said it could conceivably clog and seize the engine. Yes, the oil screen was meant to catch big pieces of metal, but the oil filter will catch those pieces just as well. So it's uneccesary.

Anyone share that judgement?

Thanks,

Paul

tacchi88 · #2 01-28-2006, 08:42 PM

It seems funny how the majority of 4 cycle internal combustion engines, have oil pick up screens. If you value your pocket book as well as your bacon, I would stronly suggest that you do not heed his advice on this matter.
Safe flying
T88
RV10 with screen

szicree · #3 01-28-2006, 09:21 PM

I've never been inside a Lycoming, but on a car the screen is there to protect the oil pump. Sure the filter would catch a piece of metal, but only after it's torn up the oil pump. Up in the sky, behind an aircooled engine, I want that oil pump alive and well at all times.

gmcjetpilot · #4 01-28-2006, 10:54 PM

It's not necessary if there are no big chunks in the oil pan. Right the screen is course and lets most items thru. The screen is not a filter, but is serves a very important purpose.

Lets say a clip, a piece of safety wire, or a chunk of aluminum breaks off the piston. The engine may be flailing but still running, even with some major damage. You want that screen from sending big chunks thru the engine and causing more damage or blockage. It is a first line of defense.

I had an O235 blow a piston; after disassemble there was metal caught by the screen. I was able to land with the other 3 pistons. Also once I had a Chevy small block 327 piston go to lunch. The remains where all in the oil pan. Again the pump screen keep the metal, at least the big pieces, from getting further into the engine. What is the advantage of leaving it OFF?

George

jarhead · #5 01-29-2006, 04:28 PM

Quote:

Originally Posted by pboyce

A very experienced A&P at my field, whose judgement I respect, strongly suggested that since I have an oil filter on my 180hp Superior engine, the oil screen was completely uneccesary. In fact, he said it could conceivably clog and seize the engine. Yes, the oil screen was meant to catch big pieces of metal, but the oil filter will catch those pieces just as well. So it's uneccesary.

Anyone share that judgement?

Thanks,

Paul

Leave the screen in place. It doesn't restrict oil flow at all, unless your engine is shedding lots of metal chunks.

Mark Burns · #6 01-29-2006, 05:13 PM

I was doing an annual on a C-172 (0-320) once and found the oil screen nearly clogged with carbon deposits. It was bad. But the engine was in good health.

I don't think the screen had been checked for a very long time, if ever. It's sort of a pain, and messy to get it out. I think the oil screen inspection is sometimes just pencil whipped.

On these aircraft engines there's more interaction with the oil and combustion gases than there is in your pick-up truck. (hopefully)
This is due to the clearances needed to operate over such a wide temperature range. (I know, everyone here knows that but just in case).

So, it's not just chunks of metal the screen is keeping out of the oil pump.
I'd say check it every other oil change and if it still looks perfect then you can stretch the inspections out some.

jonbakerok · #7 01-30-2006, 07:49 AM

When I swapped out the break-in oil on my new Lycoming, I checked the screens and found big chunks of white telflon gasket sealer from the assembly process. I'm glad those screens were there. But I've never found anything since. Makes me wonder if the "carbon" someone said they found once in an old Cessna might have actually been chunks of Permatex #2.

tacchi88 · #8 01-30-2006, 07:56 AM

Mark,
You are so correct in your assessment. AC engines are notorious oil guzzlers, and use mediocre lubricants to boot, save for some of the multigrades. At every revolution of the engine, there is "blow by" which form those carbon depisits you pointed out. Those deposits harden with time and if ingested directly into the system, it acts as an abrasive. Even with oil sampling, due to the fact that there is such a high number of these deposits, it is not regarded with great concern, but in the mean time it is performing it's duty, to shorten the life of the engine. Who cares about a simple little screen

T88
RV10

sf3543 · #9 01-30-2006, 09:55 AM

On top of all of the above comments, most of the oil filters we use have an internal bypass valve. If the filter goes into bypass mode, for whatever reason, none of the oil will be going through the filter.

mahlon_r · #10 01-30-2006, 10:19 AM

Paul, The oil filter is AFTER the oil pump and the finger screen is BEFORE the oil pump. The finger screen's job is to prevent pieces that are big enough to damage the oil pump and that might cause the oil pump to fail, from ever getting that far. Yes, the pick up screen can clog up but it takes a real lot of material to do that. Personally, I don't think that clogging is a consideration for removing it. I would strongly recommend that you leave the finger screen intact and installed.
Good Luck,
Mahlon
"The opinions and information provided in this and all of my posts
are hopefully helpful to you. Please use the information provided
responsibly and at you own risk."