Advice wanted: Metal in oil filter element

[toto]

Background: For years now, I’ve been having the shop do an oil+filter change every 50 hours, and I do an oil drain and refill myself at 25 hours (keeping the filter in place for two 25-hour rounds). 

This past week, I did my own 50-hour oil+filter change. No problems, everything per normal. I flew the plane for 1.5 hours yesterday, no problems.

Today I cut open the filter to examine the element and there’s some ferrous metal. I didn’t even notice it when I pulled the element apart, because the bits are really tiny. But when I ran a magnet over it, the magnet became pretty popular (photo below).

Since I usually have the shop do the filter change, I have no idea what the filter element normally looks like. They have always given it a clean bill of health with a “cut open filter, no metal found” kind of thing.

I understand that I can mail off the filter element to some analysis firm and they can give some advice about where the metal is likely coming from. Is that worth doing? What does the hive mind suggest for next steps?

Probably worth noting that the engine has a newish chrome cylinder, replaced about two years ago (~150 hours). The engine TSMOH is about 700 hours.

[DXB]

26 minutes ago, toto said:

Background: For years now, I’ve been having the shop do an oil+filter change every 50 hours, and I do an oil drain and refill myself at 25 hours (keeping the filter in place for two 25-hour rounds). 

This past week, I did my own 50-hour oil+filter change. No problems, everything per normal. I flew the plane for 1.5 hours yesterday, no problems.

Today I cut open the filter to examine the element and there’s some ferrous metal. I didn’t even notice it when I pulled the element apart, because the bits are really tiny. But when I ran a magnet over it, the magnet became pretty popular (photo below).

Since I usually have the shop do the filter change, I have no idea what the filter element normally looks like. They have always given it a clean bill of health with a “cut open filter, no metal found” kind of thing.

I understand that I can mail off the filter element to some analysis firm and they can give some advice about where the metal is likely coming from. Is that worth doing? What does the hive mind suggest for next steps?

Probably worth noting that the engine has a newish chrome cylinder, replaced about two years ago (~150 hours). The engine TSMOH is about 700 hours.

That’s a fair amount (hard to tell exactly how much based on scale of image), highly suggestive of cam/lifter spalling. Having your mechanic measure how far the  valves move when turning  the crank may give you confirmation. It’s worth looking at the previous filter if you can get it so you have a trend. Also review lycoming guidance for monitoring once you find metal: https://www.lycoming.com/content/suggestions-if-metal-found-screens-or-filter

Sadly, if I were wagering here, I would bet on an overhaul in your near future. It’s not terribly dangerous to run it more, but at some point the metal flakes can trash other components, making your overhaul much more costly 

[Aaviationist]

I wouldn’t call that “too much”. Pull your filter the next 25 instead of 50 and see what you e got. 

[Hank]

I think Lycoming's guidance is a teaspoon or two; that looks like a common magnetic retriever about 1/4" diameter, so you're still a tiny bit of the permitted amount.

Watch it and see what happens in the future. Cutting the filter open at your next oil change may help, just realize that if it's at 25 hours and this one was at 50 hours, if nothing changes, you will have 1/2 of what you see here.

[cliffy]

Point to remember

An oil analysis will not "see" large particles like what you have on the magnet.

Its designed to "see' only microscopic particles. 

So an analysis may not report anything wrong.

Follow the above Lycoming report on how the move from here on. 

[toto]

2 minutes ago, cliffy said:

Point to remember

An oil analysis will not "see" large particles like what you have on the magnet.

Its designed to "see' only microscopic particles. 

So an analysis may not report anything wrong.

Follow the above Lycoming report on how the move from here on. 

I didn’t mean an oil analysis - I meant an oil filter analysis, where they examine any debris in the filter element. 

I have no experience with this, so I don’t know if it’s snake oil. But there are companies that provide the service like 

https://avlab.com/product/oil-filter-analysis-kit/

[Hank]

3 minutes ago, toto said:

I didn’t mean an oil analysis - I meant an oil filter analysis, where they examine any debris in the filter element. 

I have no experience with this, so I don’t know if it’s snake oil. But there are companies that provide the service like 

https://avlab.com/product/oil-filter-analysis-kit/

That's interesting. I'd only heard of oil analysis, not filter analysis. 

[DXB]

16 minutes ago, toto said:

I didn’t mean an oil analysis - I meant an oil filter analysis, where they examine any debris in the filter element. 

I have no experience with this, so I don’t know if it’s snake oil. But there are companies that provide the service like 

https://avlab.com/product/oil-filter-analysis-kit/

In this case it will tell you that you have ferrous metal, which you already know.  It may underestimate the amount since you already pulled much of it off the filter with a magnet. It’s more informative for non-ferrous debris

[cliffy]

Some are good enough to tell you what bearing is failing but that's mostly for turbine equipment.

Again just follow the Lycoming guidance

[toto]

29 minutes ago, DXB said:

In this case it will tell you that you have ferrous metal, which you already know.  It may underestimate the amount since you already pulled much of it off the filter with a magnet. It’s more informative for non-ferrous debris

I’m going to let the element dry out over the next day or two and give it another go with the magnet. It was still pretty wet when I looked at it today, and I want to be sure I know how much is really in there.

$75 is pretty cheap if the filter analysis gave useful information, but as you said, if it’s really just ferrous vs non-ferrous, I think I already know the answer to that

 

[toto]

15 minutes ago, cliffy said:

Some are good enough to tell you what bearing is failing but that's mostly for turbine equipment.

Again just follow the Lycoming guidance

The Lycoming guidance is useful, but some of it is hard for me to gauge. Like whether it’s 1-9, 10-20 or 20-40 pieces.

I may have to give it another go with the magnet and then try to separate and count the tiny little things. I’ll try to get a really accurate count and a really accurate size estimate. 

[AndreiC]

7 minutes ago, toto said:

The Lycoming guidance is useful, but some of it is hard for me to gauge. Like whether it’s 1-9, 10-20 or 20-40 pieces.

I may have to give it another go with the magnet and then try to separate and count the tiny little things. I’ll try to get a really accurate count and a really accurate size estimate. 

The Lycoming guide refers to counting pieces only when they are big enough. Yours is more like dust. For those you use the total quantity (like fractions of a teaspoonful, as mentioned above).

[toto]

15 minutes ago, AndreiC said:

The Lycoming guide refers to counting pieces only when they are big enough. Yours is more like dust. For those you use the total quantity (like fractions of a teaspoonful, as mentioned above).

You’re right. I was looking at Lycoming service instruction 1492D, which is more focused on the quantity of debris items. 

[PT20J]

Analysis will tell you the alloy. Lycoming can tell you what parts use that alloy.

My mechanic likes to put the element in a big jar and fill it with solvent and shake it vigorously and then strain the solvent through a coffee filter. 

[toto]

5 minutes ago, PT20J said:

Analysis will tell you the alloy. Lycoming can tell you what parts use that alloy.

My mechanic likes to put the element in a big jar and fill it with solvent and shake it vigorously and then strain the solvent through a coffee filter. 

That seems like a pretty good approach. 

[Bartman]

Don't forget the finger screen at the rear of the engine.  You don't want to miss out on that fun, and you might find something.  

I did mine last month.

[LANCECASPER]

10 hours ago, toto said:

Background: For years now, I’ve been having the shop do an oil+filter change every 50 hours, and I do an oil drain and refill myself at 25 hours (keeping the filter in place for two 25-hour rounds). 

This past week, I did my own 50-hour oil+filter change. No problems, everything per normal. I flew the plane for 1.5 hours yesterday, no problems.

Today I cut open the filter to examine the element and there’s some ferrous metal. I didn’t even notice it when I pulled the element apart, because the bits are really tiny. But when I ran a magnet over it, the magnet became pretty popular (photo below).

Since I usually have the shop do the filter change, I have no idea what the filter element normally looks like. They have always given it a clean bill of health with a “cut open filter, no metal found” kind of thing.

I understand that I can mail off the filter element to some analysis firm and they can give some advice about where the metal is likely coming from. Is that worth doing? What does the hive mind suggest for next steps?

Probably worth noting that the engine has a newish chrome cylinder, replaced about two years ago (~150 hours). The engine TSMOH is about 700 hours.

The most obvious answer is that the shop probably hasn’t been cutting open your filter. Or if they have been, they are expecting not to find anything so they don’t look very closely.

$75 to have the filter analyzed is nothing in aviation dollars, But doing everything you’ve done so far with the filter may alter the results that they would find. If it was me I’d still send it and the next one to see what they find. I’d also sample the oil and send it off.  I wouldn’t just assume it’s the new chrome cylinder breaking in. Pure chromium is not magnetic, but the alloy that they use in cylinder I believe has a weak magnetic attraction. The engine making metal on Lycomings is usually the cam lobe or lifters coming apart. Assume the most likely, hope for the best. 

[DXB]

10 hours ago, toto said:

The Lycoming guidance is useful, but some of it is hard for me to gauge. Like whether it’s 1-9, 10-20 or 20-40 pieces.

I may have to give it another go with the magnet and then try to separate and count the tiny little things. I’ll try to get a really accurate count and a really accurate size estimate. 

Yes you need to run a strong rare earth magnet across the entire surface of the filter - you will likely find lots more.  I bet what you have already is 40+ pieces though.  This is what my magnet looked like when I had one cam-lifter pair spall...they are small flecks, likely very similar to yours on closeup, but very hard to count.  Note this phenomenon may decrease considerably if you run it long enough to keep wearing down the cam lobe, and the only operational difference you may notice is subtly decreased power.  BTW I do all my own oil changes, but when this happened I had gotten lazy and was only cutting open every other filter.  I pulled the previous one off the shelf and found the same thing. I flew it one more time after that, to the engine shop.

 

 

 

[EricJ]

That's definitely enough to pay attention to.  The expectation is that you see a few flakes here and there, but not very much accumulation on the magnet.   You've got a fair amoutn on the magnet, which means you need to pay reasonable attention to how the engine is behaving and closely monitor the filter during subsequent oil changes.   Starting an oil analysis program now might not be as useful as it could be, since the real strength of oil analysis is monitoring trends.   If you start an oil analysis program now it could still be useful, but there's already some wear going on somewhere.

I don't think what you're seeing is anything to get too stressed over, but definitely suggests that you should closely monitor what the engine is doing.   And +1 to follow the Lycoming guidance on metal in the filter.   Mine made a significant amount of metal for a period of time but it turned out to be the prop governor failing.   Once that was replaced it returned to normal.

[MikeOH]

@EricJ

When your governor was making metal did you notice any rpm/control anomalies?

[EricJ]

2 minutes ago, MikeOH said:

@EricJ

When your governor was making metal did you notice any rpm/control anomalies?

Not until it failed completely, which was evident during a runup one day.   It was fine until that.

[Wingover]

16 minutes ago, EricJ said:

Not until it failed completely, which was evident during a runup one day.   It was fine until that.

How did you know the metal was from the governor and not something else?

[MikeOH]

12 minutes ago, Wingover said:

How did you know the metal was from the governor and not something else?

 

2 hours ago, EricJ said:

Mine made a significant amount of metal for a period of time but it turned out to be the prop governor failing.   Once that was replaced it returned to normal.

 

[A64Pilot]

That to me on a mid time engine is NOT normal, I can buy maybe what Lycoming says is OK on a new overhaul, but a mid time engine in my experience makes essentially no metal in 50 hours. I’ve seen what amounts to a tiny bit of powder so fine it feels like grease on internal filter magnets that is normal. I’m talking like maybe a drop total, which is I guess 1/4 of a CC or less?

Just because you have metal now doesn’t mean it was there last time, if it made this much every 50 hours there wouldn’t be any left. So we can’t make any judgement calls on the prior mechanics inspections.

I think investigation is in prudent myself, especially if you fly nights or IFR

[Fritz1]

yes, by all means, further investigation is prudent, I think there is a contorted way to stick a borescope into the engine, either through the oil filler spout or through the oil drain, I have never done it myself, your A&P will know, then you can see at least one cam lobe, this lobe may already give you the answer, the evil you know is better than the evil you don't know, I keep fingers crossed!