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Does Oil Analysis Work?

avrojockey

avrojockey

Well Known Member
Patron
I say...yes!

I made NO indication on my Blackstone slip that small amounts of ferrous metal had been found in the oil filter to see if it could be caught in the sample analysis, only that there was a small chunk of inactivity in the January while I was in training.

At the time I took the sample, I knew there was a bit of metal but I had not known the source (eventually determined to be cam/lifter).

I knew analysis was good tool, but now I highly recommend! Blackstone nailed it!
 

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science does not lie

But scientists do....
I am not saying Blackstone lies but plenty of scientists do, depending on who pays for the report or analysis.

Flying regularly, (often) and changing your oil at set time or calendar intervals is probably better "science" than oil analysis.
Seeing elevated ferrous material in your oil analysis is probably a good foreteller of bad things to come. Like many of our modern gadgets that give us insight to information we did not have 30 years ago, oil analysis is yet another tool to help us sleep better. I religiously sent in oil samples on my last plane but decided to skip it on my IO 540, but I make sure I fly a lot and I sleep just as well.
 
What did they tell you that you didn't already know? You found iron. They found iron. You thought it was because of inactivity. They thought the same thing.

And what are you going to do with this information?
 
My engine builder's wisdom:

Oil analysis is great for trend monitoring if you are operating consistent hours in a consistent environment, like an enclosed generator set or mining haul truck in the Pilbara. But any Cat mechanic will tell you all operators and mechanics do the same thing, which is replicated in Aviation word for word... If a concerning report comes back, they change the oil and inspect the filter, all being ok ,send it back out for a set period of time and retest. We have never seen an aircraft engine grounded on the findings of an oil analysis report, only by what is in the actual filter or suction screen so it does beg the question, why do it in the first place?
Click to expand...

(This guy built Red Bull Air Race engines, and is very well known in Australia)

- mark
 
If you have a working plane that is flown on a regular basis (more than a hour a week) sure, trend analysis.
 
‘Oil analysis is great for trend monitoring if you are operating consistent hours in a consistent environment, like an enclosed generator set or mining haul truck in the Pilbara. But any Cat mechanic will tell you all operators and mechanics do the same thing, which is replicated in Aviation word for word... If a concerning report comes back, they change the oil and inspect the filter, all being ok ,send it back out for a set period of time and retest. We have never seen an aircraft engine grounded on the findings of an oil analysis report, only by what is in the actual filter or suction screen so it does beg the question, why do it in the first place?”

Totally agree with the above, never had anyone say the engine needs an OH based on oil analysis, so why do it.
 
StuBob said:
What did they tell you that you didn't already know? You found iron. They found iron. You thought it was because of inactivity. They thought the same thing.

And what are you going to do with this information?
Click to expand...

There are some that believe the analysis isn't worth it. In this case the iron was visually detected and validated with analysis. It did not tell me what I already knew but it validated my decision to spend money on it. Iron is about he simplest thing to detect in a filter...other elements, not so much. Sure, you may have bits of AL from pins caps easily detected, but more subtle things are much more difficult to catch and require trend analysis. The analysis catching the iron gives me confidence to the other parts of the sample. If I was only looking for iron, I probably wouldn't bother.

Additionally, 1 month inactivity in a WI January did not cause this. Something else in play.
 
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newt said:
My engine builder's wisdom:



(This guy built Red Bull Air Race engines, and is very well known in Australia)

- mark
Click to expand...

So the Cat mechanic defies all logic in continued application of wasting resources? This statement doesn't even make sense...I'm willing to bet, given the extensive mining enterprise in AU, and therefore presumably the millions spend on oil analysis in this industry, at some point, some accountant has made the determination it is worth it fiscally let alone functionally.
 
Walt said:
Totally agree with the above, never had anyone say the engine needs an OH based on oil analysis, so why do it.
Click to expand...

Walt, I know you're not saying the only time you need to maintain an engine is when it's time to overhaul. However, that's exactly how this statement reads. Surely an once of prevention is worth a pound of cure, and an entire industry of analysis was not birthed and thriving based on fear and ignorance.

I don't do this to make me feel good inside. I do it because it adds value to the safety system...a logbook entry from a human (eg. fallible) A&P that visually inspected the filter element is a completely different value than an independent lab spectrographic analysis of oil.
 
avrojockey said:
So the Cat mechanic defies all logic in continued application of wasting resources? This statement doesn't even make sense...I'm willing to bet, given the extensive mining enterprise in AU, and therefore presumably the millions spend on oil analysis in this industry, at some point, some accountant has made the determination it is worth it fiscally let alone functionally.
Click to expand...

In the mining case: The accountant has made the determination that it's worth it fiscally because the oil analysis use case for a mine haul truck is different from the one you're talking about.

In the mine haul truck, the oil analysis is used to extend maintenance: "This engine has done N hours which the book says means I need to pull it out of service for a week to do some checklist maintenance, but oil analysis is helping me to see that everything's fine so I'm going to let it stay in service for another three months and see what happens."

You're trying to do the opposite: "I already know there's a problem with the engine because I've poured 3 lb of iron filings and a mud dauber wasp nest out of the oil filter, and I'm going to use oil analysis to help direct my scrutiny during the tear-down."

The mines are using oil analysis to get extended economic life out of their diesel engines, avoiding unnecessary expensive downtime. You've already decided to accept expensive downtime, using factors other than oil analysis to make the decision. So I'm not sure how oil analysis has actually helped you here.

- mark
 
Just a single data point, but worth noting. In 2011, the crankshaft gear in my engine began disintegrating. I found a lot of metal in the filter, none in the screen. The oil analysis done showed no increase in iron or any other component.

Screens and filters are your first indication something bad and potentially catastrophic is happening. Oil analysis might tell you something is wearing unusually. YMMV. I'll report back after this upcoming (May) analysis, as the plane sat unused for almost 3 months this winter.
 
Short term or long term.

The oil analysis does not lie. The high iron in the oil for many of Tims analysis reports indicated some internal issue that was progressing. If it was a multi-million dollar piece of equipment, they would have addressed this long ago.

20 for iron is too much. This should have alerted Tim that it was either an operating procedure - i.e. internal corrosion between each flight, or something mechanical going wrong and a decision made on what to do.

If this was a Cat engine, then as soon as the iron exceeded 4-5 the customer would have been alerted that the air filtration system should be inspected. Air leak, filter change, or brand of filters was not up to par. This happens quite often. Mining trucks and other heavy duty Cat engines (transmissions, hydraulic systems etc) will have a TBO of 20-40,000 hours. A longer term outlook.

It really depends on what we are looking for the analysis to do. Most don't keep the engine to over haul so don't much seem to care if it is 1800 or 3600 hours. With this situation, the oil analysis is of little value as it won't be acted on. The plane might be sold or engine removed, sold, and replaced with "new".

Discounting TBO, if one wants to see if a rapidly occurring threat to operation is beginning, then analysis will show it, but so will regular filter inspections. This is Walt's most excellent point. (and newt/Mark's too)

Why aren't our engines in the 3 ppm Fe range? Crappy air filtration is the prime issue if frequent flights eliminate static corrosion.

If Tim was about to depart on a round the world event then the oil analysis would have said, beware.
 
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Right before my IO-520 tear down, in which the crank and cam were so far out of spec that both had to be replaced, Blackstone sent me a report saying “this Continental is aging like a fine wine.”

So I disagree with the statement that oil analysis doesn’t lie.
 
StuBob said:
Right before my IO-520 tear down, in which the crank and cam were so far out of spec that both had to be replaced, Blackstone sent me a report saying “this Continental is aging like a fine wine.”

So I disagree with the statement that oil analysis doesn’t lie.
Click to expand...

The data or the interpreter?
 
avrojockey said:
There are some that believe the analysis isn't worth it. In this case the iron was visually detected and validated with analysis. It did not tell me what I already knew but it validated my decision to spend money on it. Iron is about he simplest thing to detect in a filter...other elements, not so much. Sure, you may have bits of AL from pins caps easily detected, but more subtle things are much more difficult to catch and require trend analysis. The analysis catching the iron gives me confidence to the other parts of the sample. If I was only looking for iron, I probably wouldn't bother.

Additionally, 1 month inactivity in a WI January did not cause this. Something else in play.
Click to expand...

You don't know which Iron pariccles they detected and you had two issues going on - corrosion from inactivity and cam spalling. They use mass Spectrometers and they only see microscopic things. THe cyl wall corrossion from inactivity gets scraped off by the rings and creates very fine iron particles and likely this is what they caught. Cam spalling tears chunks off the lifter body close to 1/16" in length. The Mass Spec cannot see that, though they may see the finer particles that also are created in the spalling process. However, most of the debris from spalling is chunks, as you saw in your filter. I had my piston pin caps wearing away. Oil filter looked like someone poured a jar of glitter in my oil (I had confirmed that the glitter was Aluminum with an acid test). OIl analysis came back with a well below average level of aluminum (including a smiley face) and this makes senses as in my failure mode it was not wear creating microscopic stuff but tearing off chunks of material. It does not catch all issues. It is a tool, but lick any tool it can only do certain things.

PLEASE do not trust oil analysis to identify ALL problems. Cutting open the filter is a critical step. In your case, the cam issues created both fine particles and chunks. However, the reading was not high enough to indicate a serious issue like cam spalling as it could have been several benign sources. Monitoring trends is a two tool job. The oil analysis helps to track the things you cannot see and the filter examination tracks the things you can see.

Don't know about WI, but down here in Chicago we had one of the warmest Januaries on record with the avg right around mid to upper 30's. Plenty of moisture in the air at those temps.

Larry
 
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I used to do this, as it was something like $20 including shipping - very reasonable. Then the price doubled, then it tripled, then I gave up on it. Nice to have, but not worth the expense anymore especially given the likelihood of it "saving your engine", let alone saving your life, is actually insignificant.
 
I see oil analysis as a tool in my tool box. It's not a panacea and IMO should be used to compliment all of the other tools (filter examination, borescope, compression checks, etc) in order to take a holistic view of engine health.
 
ditto

Auburntsts said:
I see oil analysis as a tool in my tool box. It's not a panacea and IMO should be used to compliment all of the other tools (filter examination, borescope, compression checks, etc) in order to take a holistic view of engine health.
Click to expand...

thanks exactly what I was thinking. been testing for a long time now.
I have my two 300 r OB on the program and it is a big help. :D
 
newt said:
In the mining case: The accountant has made the determination that it's worth it fiscally because the oil analysis use case for a mine haul truck is different from the one you're talking about.

In the mine haul truck, the oil analysis is used to extend maintenance: "This engine has done N hours which the book says means I need to pull it out of service for a week to do some checklist maintenance, but oil analysis is helping me to see that everything's fine so I'm going to let it stay in service for another three months and see what happens."

You're trying to do the opposite: "I already know there's a problem with the engine because I've poured 3 lb of iron filings and a mud dauber wasp nest out of the oil filter, and I'm going to use oil analysis to help direct my scrutiny during the tear-down."

The mines are using oil analysis to get extended economic life out of their diesel engines, avoiding unnecessary expensive downtime. You've already decided to accept expensive downtime, using factors other than oil analysis to make the decision. So I'm not sure how oil analysis has actually helped you here.

- mark
Click to expand...

You're right...It didn't help me in this circumstance but it validate the process because, like you, I questioned it
 
lr172 said:
You don't know which Iron pariccles they detected and you had two issues going on - corrosion from inactivity and cam spalling. They use mass Spectrometers and they only see microscopic things. THe cyl wall corrossion from inactivity gets scraped off by the rings and creates very fine iron particles and likely this is what they caught. Cam spalling tears chunks off the lifter body close to 1/16" in length. The Mass Spec cannot see that, though they may see the finer particles that also are created in the spalling process. However, most of the debris from spalling is chunks, as you saw in your filter. I had my piston pin caps wearing away. Oil filter looked like someone poured a jar of glitter in my oil (I had confirmed that the glitter was Aluminum with an acid test). OIl analysis came back with a well below average level of aluminum (including a smiley face) and this makes senses as in my failure mode it was not wear creating microscopic stuff but tearing off chunks of material. It does not catch all issues. It is a tool, but lick any tool it can only do certain things.

PLEASE do not trust oil analysis to identify ALL problems. Cutting open the filter is a critical step. In your case, the cam issues created both fine particles and chunks. However, the reading was not high enough to indicate a serious issue like cam spalling as it could have been several benign sources. Monitoring trends is a two tool job. The oil analysis helps to track the things you cannot see and the filter examination tracks the things you can see.

Don't know about WI, but down here in Chicago we had one of the warmest Januaries on record with the avg right around mid to upper 30's. Plenty of moisture in the air at those temps.

Larry
Click to expand...

Definitely not relying solely on analysis for anything. Thanks for pointing that out.

When I was gone I remember it was pretty cold. I was was in Dallas and teasing my wife about the nice weather. Appleton is far enough from the border to cause a noticeable difference between it and Chicago, where I usually work. Plus I have an engine dehydrator.

This is where it gets interesting, and what I think happened: I installed the ASA oil separator. This didn't cause it, but the dehydrator is a closed loop system that I did not modify to keep closed loop with the breather now attached to the PCV. Dry air was displacing the moist in the case, but the water was going out the breather, to the separator, condensing, and returning back to the case. When I took the drain-back line off, water came out. This caustic solution had been going right back to the case, so the dehydrator wasn't doing anything unmodified. In fact I remember checking my oil the first flight after the break and seeing ice crystals at the top of the oil level on the dip-stick. I had never seen that before and considered it pretty strange considering the dehydrator was hooked up. It all makes sense post-mortem but at the time I blew it off.

There may be evidence in analysis something was happing before this. However, the dehydrator, as currently designed, didn't help. I definitely need to reverse the flow so water isn't condensing in the separator.
 
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Auburntsts said:
I see oil analysis as a tool in my tool box. It's not a panacea and IMO should be used to compliment all of the other tools (filter examination, borescope, compression checks, etc) in order to take a holistic view of engine health.
Click to expand...

In what way does it complement other sources of information? ISTM that it either agrees with the other information and adds nothing or disagrees with the other information and adds confusion.
 
StuBob said:
In what way does it complement other sources of information? ISTM that it either agrees with the other information and adds nothing or disagrees with the other information and adds confusion.
Click to expand...

Whatever makes you feel happy. I'm not trying to convince you one way or another. For me it's another source of data because one tool might not indicate a problem whereas another does. It can also help perform differential diagnostics and help narrow an issue down or identify a lurking issue. For me it's a cheap tool worth using. For others maybe not so much. YMMV.....
 
35 BUCKS

71459 said:
I used to do this, as it was something like $20 including shipping - very reasonable. Then the price doubled, then it tripled, then I gave up on it. Nice to have, but not worth the expense anymore especially given the likelihood of it "saving your engine", let alone saving your life, is actually insignificant.
Click to expand...

Not a clue who you use but mine is $ 35.00 and just went up 5.00 including shipping.
 
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