Making a Little Bit of Metal
 

So over the past two years, the iron in my oil samples has been slowly creeping up. But the filter was always clean so I just kept an eye on it.

On my last oil change however, I was able to tease a little bit of ferrous particles out of the filter with a magnet.

The engine is a Lycoming O-360-A1D with Bendix mags, about 600 hours since factory re-man.

Here's the oil data:



Filter at first glance looks pretty clean:



But with a magnet, I'm able to pull out tiny ferrous particles:



The engine has been running great. And I watch my CHTs like a hawk. Here's a recent flight:



Blackstone still thinks it's not urgent, and recommends checking back in 30 hours. But I did find something that was worrisome--a possible crack in the engine mount:



Hard to tell if the crack goes through the paint or not. But the fact that it runs along the tube has me worried. Could vibration also cause some wear inside the engine?

At this point, I'm inclined to take Blackstone's advice. But I'd love to hear the thoughts of the engine guys out there.

-Matt
N402BD

Could be the picture, but that looks more like a rub mark from something than a crack on the engine mount. In any case, a crack is much more likely to occur at a weld, and be circumferential, than lengthwise.

A problem with the engine mount also will not be connected to a rise in ferrous metals in the oil analysis. You are chasing two different problems, unrelated, and one of which may not be a problem at all.

Tiny Cracks
 

Greg,

In the picture, the cracks on the mount are the things that look like scratches. Very fine, but definitely cracks in the paint. Just not sure if the tube underneath is also cracked. Seems like a strange place for that to happen. I'll keep an eye on it.

As for the metal, Blackstone suggested that it might just be "the new normal" for my engine. And I'd hate to start tearing it apart if that's the case.

I'll probably fly another 20 hours or so, change the oil, and see how it looks.

-Matt
N402BD

Mike Busch
 

Mike Busch wrote a very good article about how much metal is too much. That sort of thing. Look it up in the EAA archives.

Great Tip
 

Of course. A quick google search reveals that Mike Busch has written a couple of articles on the subject. And Lycoming has issued some guidance in the form of Service Instruction 1492C.

Turns out in my case, since Aluminum is not elevated and the particles in the filter are few in number and smaller that 1/16", Both Mike and Lycoming recommend putting the plane back in service and checking again at the next regular oil change. So that's what I'll do.

Thanks guys!

-Matt

Your profile does not say where you are - like humidity and temperature environment. Looking at the time between changes, it appears the plane can sit a while. Depending how you fly - short vs long times, and how long the oil is hot, and if you use heaters it could be some mild corrosion due to internal moisture.

Silicon is not elevated, so it is not getting dusted.

If that is the case then changing your routine may help drop the iron. May not, but worth a try.

Do you have an oil separator or a straight exit breather?, is there any water related whiteness/condensate on the dipstick?

All these thing might give some clues, or it is a piston pin scraping the cylinder wall, or a slowly eroding cam/lifter unrelated to operation and nothing to do but open ad repair. In any case, more investigation is in order to prevent proper discovery of the root cause later on. No use in getting oil samples if no action is taken on the results. It may, indeed, be a fundamental issue unrelated to anything but chance.

PRL - what kind of barrels, and rings? Probably not ring de-lamination as oil consumption would be rising, so scratch that.

I really don't like iron in the filter after the initial oil changes cleans everything out. Good luck.

Some Sitting
 

Bill,

The airplane did spend some time as the hangar queen while I was overseas in 2012 and again in 2014. Plus I missed a sample on an oil change in 2014. When the plane was sitting (maybe two months tops), it was in New Mexico. So I'm hoping corrosion is not the issue. But I have been in South Dakota the last two years where there is a touch of humidity in the summer.

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

Straight Breather
 

Also, straight breather tube. Normally I don't see any moisture in the little bit of oil that drips out while the plane is sitting in the hangar. But after the last cold snap, I did see some.

-Matt

It sounds like it is not corrosion, so it is something else. Yes, SD should be pretty low in all around humidity, and there were no spikes in iron, so less chance of corroded cylinder walls. Jug inspection through spark plug hole seems in order, but inspect the particles magnified, or send a collection of particles to Blackstone for metallurgical analysis. That would help identify the source.

Lifters could be another consideration, but an analysis should help narrow that down. Sorry, we could not be more help.

A Little Extra Ins!
 

....You may want to consider one of these. It will catch all the ferrous materials, prior to them going through and damaging the oil pump. It will also catch all the particles too small to be caught in the filter. When removed it will give you a 100% visual of all this type of material that has been generated in your engine, making comparisons from one oil change to the next very easy.
Thanks, Allan..:D:D
http://antisplataero.com/Magnetic_Super_Plug.html

Worth a Shot
 

Just sent you an order via paypal.

-Matt

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.

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

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

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.

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

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

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

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

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.

You can put the cam on the base circle and see if the hydraulic lifters are out of range - dead giveaway. If that occurs, the plane should be grounded.

The pieces can break off the edge of the cam lobes after the followers become concave (if they are not rollers) and create edge loading.

Lots of speculation - a good magnified photo should narrow the scope.

Something is definitely happening, but just when it needs repair is not clear yet from information available.

Power?
 

Bill,

If the lifters were out of range, would that affect performance? The engine has been running like a champ.

I'll see if I can get better pictures of the particles and maybe get them analyzed. I hate to start performing exploratory surgery unless there's no other choice.

-Matt

Probably not early in it's progression, if that's it. Maybe after lash range was exhausted, the CHT would creep downward relative to other jugs as the first indication. Email sent.

Once a cam/lifter wears enough to be noticeable it is not likely to stop; It will typically take out the whole lobe. I have no first hand experience with lycoming cam failure due to spalling. However, an engine that is throwing off chunks the size shown in your pictures is not doing well in some area. Most cam/lifer wear will not generate chunks of steel like you are showing. Once they go, they can go fast, but it is more typical wear, with much finer debris, due to surface imperfections and resulting bad geometry (i.e. concave vs convex).

I'll restate, ferrous chunks of that size need to be identified as to there source so that you can assess your risk.

Larry

Martin.
 

I can give you two cents from the peanut gallery. Pictures are sometimes hard to read and inturpret so from what you have posted I can guess but not be sure. The dark black stuff looks to be normal coke and stuff you see all the time. But the metal that is both in the finger strainer and on the magnet is a dead giveaway there is something in the engine going away. If I understand this history of this power plant correct, it has been stored from time to time and not run for months at a time. What you are seeing is what we would expect for long dry store, start damage. It is better to pull a jug or two now than wait or guess if or when something may turn loose internally in this power plant.
Sorry, I think you need to get this stuff checked and identafied then if it looks to be gear, cam, lifter or whatever metal go in and put your finger on the problem. You will be money and peace of mind ahead.
Hope this helps, Yours, R.E.A. III #80888

Making Metal
 

I was putting together a comment but Robert Anglin very clearly stated what I was thinking. Have dealt with this issue a several times and his advice is spot on.

Don Broussard A&P, IA etc etc
RV9 Rebuild in Progress
57 Pacer

I hope your results are different than mine.
For the last year I've been seeing metal in the filter on my RV-10's io-540. I found one small shard in my pick-up screen. All told, less metal than you are picturing. I had my mechanic look at what I found and he wasn't too concerned. My oil analysis always comes back normal. For piece of mind, I pulled my #3 cylinder since there was some evidence of past corrosion in there. The cylinder looked as expected. However, the tappets I could see had severe pitting and there was visible cam damage.

My engine is at Barrett as we speak. My cam and lifters are shot. There is some scoring on the crank which may or may not polish out. I should have stopped flying it earlier--it may have saved me the cost of a crank.

My engine came off a Piper Twin, and then only flew 200 hours in 7 years in my RV-10 before I bought the plane. I knew I might run into this, but I was hoping not!

Best of luck!

Guy

As to the question on loss of performance on the worn cam, I doubt you would notice anything. I have a Mustang 2 with an O-360 that I bought about 5 years ago and prior to my buying it it sat for a while and apparently got some rust on the cam which is all it takes to ruin one. Engine ran just fine until a minor prop strike and I pulled the engine apart to magnaflux the crank. I was shocked to see two cam lobes with nearly an eighth inch of wear on the end of the lobes and correspondingly ate up tappet bodies. I expected a nice increase in performance when I put the new cam in, but two engine experts said I probably would not notice any difference and I could not even tell when I flew it. And this is a plane that I keep detailed performance records on.

Sharp Pointy Particles
 

Here's a better photo of the particles on the magnetic drain plug.



I'm planning to pull the #2 cylinder when I get a free weekend. That one had the lowest compression (72) on the last annual.

-Matt

Quite a bit of metal there. Something is wearing aggressively. I would try to borrow a borescope or buy one of the dental cameras. Inside of a cylinder, I would think that only broken rings or missing pin plugs (they couldn't have worn away or you would have seen a LOT of aluminum in your filter) could cause that kind of metal. Wear on the cylinder wall should be quite visible with that kind of metal production. This would be a much faster way to check each cylinder before you pull more to check the cam. If they all look good, next step would be to pull jugs to check the cam. Seek advice on the best cylinders to pull for best visual access to viewing the cam. You should also pull the rocker covers to look for damage. Less likely, but easy to do. If it is not inside the cylinders, you're going to need a full tear down anyways, though I suppose it could be coming from the accessory case.

If you happen to have a buddy with an analyzer to determine the alloy of the fragments, Lycoming can tell you where the metal is coming from. They offered to do this for me when I was making small metal and couldn't confirm the source. I later figured out it was aluminum and never used their service. My piston pin plugs were wearing away.

Larry

At Least One Culprit Identified
 

I finally got an afternoon free to pull a cylinder--the #2. The second cam lobe looked pristine. But here's what the forward-most lobe looks like:




There's not much wear but the coating is clearly coming apart. Plus the lifter looks like it's taken some abuse. I'm not sure if that's normal.

Do you guys think I could grind it down a bit or do you think I need to pull the engine, split the case, and remove the cam for reconditioning?

Thanks,

-Matt

Stick a fork in that one!
 

Sorry to say it Matt but it's done, you are going to have to split it and repair it.

I'm with Russ - that cam follower is in worse shape than the ones they keep at the Lycomning school as absolute junk to show what junk followers look like....

Ahh...a wonderful opportunity to learn all about the inside of your engine.

There, doesn't that feel better?

Most definitely must split the case and replace the parts. Note peeling over of the edge on the cam lobe edge. It may be able to be reground but highly unlikely to reuse the cam. A follower like that is way beyond refurbish, it is scrap. The particles were most likely the spalled pieces from the pockmarks on the follower. From this condition, it could have begun rapid wear at any time, overwhelming the oil filter and pumping fine debris through the bearings. These conditions don't heal and only get worse.

Good call to pull the jug and inspect.

Cam holes?
 

I noticed there are two holes in the cam lobe, i guess for oiling. Is this a stock cam or aftermarket with the oil hole mods?

Stock
 

I bought this engine as a zero-time overhaul from Ly-Con. I presume they're stock, but I can't really say.

Can anyone recommend a good shop that can overhaul a cam? This engine only has 800 hours on it and so far everything else is looking pretty good. I plan to just IRAN everything as I take it apart.

-Matt

Aircraft Specialty Services in Tulsa, Oklahoma is a go-to vendor for most engine internals, including cams. A new cam (or a cam kit, which includes tappets, hydraulic units, etc.) isn't ridiculously expensive either...

Metal in oil
 

Hopefully no hard particles got in between the crank and main bearings. There is a risk of scoring which increases every hour it runs with metal circulating. Aircraft Specialty in Tulsa is great for the steel parts. IRAN is not a bad plan but I would strongly consider reworking the bottom end just like a major OH. Its not overly expensive once the engine is apart. If cylinders are good they could go right back on as they are relatively easy to deal with if rework is needed later. Serious cleaning/flushing of all areas that are exposed to engine oil is mandatory.

Don Broussard A&P, IA. Etc etc
RV9 Rebuild in Progress
57 Pacer

You won't be overhauling that cam, it will be red-tagged along with the lifters. I have seen this movie before. :)

N399SB engine overhaul






Do a complete overhaul of the bottom end with everything magnafluxed, replaced or yellow-tagged as necessary and you will have the foundation of a solid engine that should last a long time. The spalling of the lifters is what took out the cam and most likely is the result of corrosion due to extended periods of inactivity. By the way, the crankshaft was still good in my engine in spite of the loose metal being circulated. The engine is doing fine 17 years after overhaul: