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-   -   Making a Little Bit of Metal (https://vansairforce.net/community/showthread.php?t=135233)

MartinPred 03-02-2016 10:07 PM

Worth a Shot
 
Just sent you an order via paypal.

-Matt

G5Driver 03-03-2016 10:36 AM

Matt,
No expert here, but if you think about the heat and friction inside of an internal combustion engine, it has to show some sign of wear or they would never wear out.
Remember, these are parts per million! With your current numbers and running condition it looks like you will make TBO with proper maintenance and oil changes no problem. JMHO.

MartinPred 05-14-2017 09:20 AM

Hard to Tell
 
Since last year I installed the magnetic drain plug and ran through a couple oil changes. At first I thought I was within the Lycoming limit of 20-40 hairlike ferrous particles of 1/16" or smaller. Now I'm starting to think I'm exceeding that limit. Here's what it looked like yesterday:




That stuff on the screen is non-ferrous carbon. No large ferrous particles. Oil filter had a very small amount of super-tiny ferrous particles. Still waiting for the sample analysis.

Time to pull jugs?

-Matt

David Paule 05-14-2017 09:39 AM

Regarding the engine mount, all I could see in the photo are the large lengthwise marks that appear, as airguy said last year, to be from something scraping it.

Typically, cracks in steel tube will be associated with and adjacent to the welds. They might also be circumferential or spiraling. I doubt there will be any lengthwise cracks unless the tube itself was manufactured poorly.

If you remove a bit of finish around a suspected crack, you might be able to tell with a 10x magnifying glass, called loups. A friend recently showed me a 40x one that included a tiny LED. Amazon sells inexpensive ones in that range. Better ones are Bausch & Lomb Hastings Triplet Magnifier, for a bit more money but still reasonable. For the visual inspection, 10x is sufficient.

A more rigorous test, also more expensive, would be something like dye penetrant test, and Aircraft Spruce sells those. You can do that with the engine mount in place.

Dave

BillL 05-14-2017 10:33 AM

Fuzzy
 
That picture is hard to see. There are places that will analyze the particles and tell you what they came from, esp the ferrous ones. It could be a spalling lifter/cam, or a spalling gear. A better photo can tell if these are sheared pieces or spalled particles. They look like spalled generated.

Can you get a better focused and magnified photo of the particles? I have a little attachment for my iPhone that makes fantastic close up photos.

What ever it is, it is not going away.

vic syracuse 05-14-2017 01:39 PM

Did you try to crush the pieces? Believe it or not, but lead deposits in the oil are magnetic. Lead becomes magnetized when heated inside the combustion chambers.

Look at them under some magnification, as mentioned earlier.

Vic

Vic

lr172 05-14-2017 01:57 PM

Quote:

Originally Posted by MartinPred (Post 1058858)
Bill,

I'm pretty sure the A1D has steel cylinders, so the most common culprit for that is the piston plug (hence the Lycoming SB). I may be pulling some jugs in the future.

-Matt

Piston pin plugs are aluminum and cylinder walls are steel. Wear at their interface will produce aluminum particles that are non-ferrous, at least until the plug is fully worn away. As someone that experienced wear here, you will see a LOT of AL material in the filter with even minimal wear. It is VERY unlikely to have your plugs completely wear away without noticing it if you routinely cut the filters open.

Larry

lr172 05-14-2017 02:11 PM

It is not normal for engines to produce ferrous metal of that size once broken in. That is not normal wear from the ring/wall interface. That would be more microscopic and picked up by the oil analysis. particles of the size shown are not represented in spectral analysis. When dealing with wear of this size, you cannot trust oil analysis for your guide. If you are producing fine and coarse particles, the oil analysis helps. If you are only producing coarse particles, OA will give you a false sense of security. When my pin plugs were wearing, I got a lot of particles in the filter, but the OA showed below normal levels of AL.

Mostly likely culprits are cam/lifer wear due to spalling or a broken ring. Next would be gear wear. A broken ring should show up in a compression test. No way to identify cam/lifter wear without a visual inspection (pull jug and look). Oil pump impellers are also a slim probability, but particles of this size should eventually cause reduced oil pressure.

Larry

lr172 05-14-2017 02:28 PM

Quote:

Originally Posted by vic syracuse (Post 1172999)
Did you try to crush the pieces? Believe it or not, but lead deposits in the oil are magnetic. Lead becomes magnetized when heated inside the combustion chambers.

Look at them under some magnification, as mentioned earlier.

Vic

Vic

Vic raises an interesting idea here. Under magnification, steel or iron shoud show fracturing and sharp edges. Lead would likely have some or all soft/rounded edges.

Larry

lr172 05-14-2017 02:32 PM

Quote:

Originally Posted by MartinPred (Post 1172983)
Since last year I installed the magnetic drain plug and ran through a couple oil changes. At first I thought I was within the Lycoming limit of 20-40 hairlike ferrous particles of 1/16" or smaller. Now I'm starting to think I'm exceeding that limit. Here's what it looked like yesterday:




That stuff on the screen is non-ferrous carbon. No large ferrous particles. Oil filter had a very small amount of super-tiny ferrous particles. Still waiting for the sample analysis.

Time to pull jugs?

-Matt

I didn't notice this pic when making my other comments. Those are LARGE particles on the magnet and, in my opinion, worthy of immediate identification, given that the magnet was not there during break in. Particles of that size don't fall into the category of wear, as we think of it. They are being caused to break off.

Carbon particle can sometimes be shiny when fractured, but I don't know if they can be attracted by a magnet. THe simple test is to put the particle in muriatic acid. Carbon or aluminum will fizz/bubble once the oil barrier is broken. Steel or iron will not.


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