Oil Analysis IO360B1E

[Jeff Oslick]

Here's another example of how we've used oil analysis: Elevated silica pointed to a damaged seal on our carb air box.

 

[OneCharlieTango]

The silicon thing makes sense. There’s no other way to look for leaky filters and I don’t think anything else will cause it to be elevated. There’s still a question of false negatives and false positives, though.

As I mentioned, we went looking for the source of the increased contaminant. Without the report it would have taken weeks/months for the damage to be caught which in most cases will cause collateral damage as well.

”Went looking” in what way?

Despite how I’m apparently coming off, I’d really like detailed answers. Every time I push on this subject I either get dismissed as a crank, or people will say that, in response to a bad oil analysis, they THEN did a borescope or cut the filter — things they should’ve done anyway.

So when you say you went looking, what did you actually do?

 

[Bell206]

I’d really like detailed answers.

I can give them to you, but first we need to put things into their proper context....

they THEN did a borescope or cut the filter — things they should’ve done anyway.

What do you mean by "things they should’ve done anyway"? It comes across as though there is some standard process that would catch every issue found on an oil analysis. Thats not correct. Not every engine has a filter nor does the TCM boroscope inspection apply. Its a flippant response and the reason you're probably viewed as a crank. So onto the detailed answers....

For example, on the piston skirt, the analysis showed a large increase in aluminum shortly after overhaul. This is a Wright R1300. We tracked it through 3 oil changes with no reduction. After discussion with the engine shop we scoped the cylinder bores with no defects noted. We were sure it was piston or fuel pump related. After the pump came clean we pulled a jug and scoped the pistons again. Found 2 that were starting to fail at the skirt. There was no filter only a screen and no borescope procedure on this 80 year old engine. Regardless we got a warranty claim and replaced all pistons before the original pistons trashed the whole engine. Does this make more sense?

I've been around/using oil analysis for many years and consider it a valuable preventative tool just as a borescope, prop balancer, and other tools. Unfortunately, a majority of aircraft owners do not understand the incremental benefits achieved by using all recommendations out there. This topic is much bigger than just using oil analysis but if you want the most out of your aircraft in component life, reliability, etc. preventing the issues is the #1 goal every owner should strive for.

 

[OneCharlieTango]

Excellent. Thanks. Do I understand that you did borescope the cylinders and didn’t see scuffing or scoring?

When I say “things they should’ve done anyway,” I’m talking about the story I hear all the time that goes, “our oil analysis came back with large amounts of bronze. SO THEN we cut the filter and it was full of this gold stuff. . . .” In this common scenario, the oil analysis adds nothing because a prudent owner/maintainer cuts every filter.

I think this is the first story I’ve heard where anyone took an engine apart based on oil analysis findings. Sounds like it was the right thing to do.

 

[Domenick]

I used oil analysis for about 15 years with my last engine. I also tracked oil/fuel consumption for every flight. I cut the oil filter, checked the sump screen, and ran a compression check at most oil changes.

I ran that O-320 engine out to 2925 hours. At a certain point the wear metals increased (not suddenly, but quickened over a year), oil consumption went up, but compressions were okay. Borescope found no abnormalities. All this indicated an engine that had quickened its ageing rate. The final straw was my reluctance to cross the Cascade Mts. with the engine. Based on all the tools, despite some indicating quickened ageing and others showing no indications, I had lost confidence in the engine. It was replaced that winter.

You don't troubleshoot an electrical system with just a voltmeter. You use an ammeter, resistance meter, capacitance meter, oscilloscope, ...

 

[Pinecone]

In most cases no you wouldnt split an engine based solely on an oil analysis. But I've personally seen when there is no oil trending and you wait till the issue shows up in the filter or it is worn to the point you can see it then the repair costs more. Thats the point of the trend. For example, we've caught several piston skirts that started to shed aluminum, a few valve tappets that were defective, and a number of other similar type issues. In most cases it was a simple part replacement or was a warranty claim instead of a major repair. I always recommend to start an oil analysis trend when appropriate. It is what it is.

If you read Mike Busch's book, he mentions some also. Where the oil analysis pointed to something that would not normally be checked, that was found to be something that would have eventually turned into a problem.

Again a tool.

 

[Bell206]

Do I understand that you did borescope the cylinders and didn’t see scuffing or scoring?

No scuffing or scoring. But if that were the case there would be different trace metals in the report and not only aluminum. This is why it is important to understand the process and what the results mean.

In this common scenario, the oil analysis adds nothing because a prudent owner/maintainer cuts every filter.

However, the oil analysis will show a rise in metal contamination long before you see it in a filter. That is the point. Curious, since you don't use an oil analysis, how do you determine what metals are present in your filter sample?

I think this is the first story I’ve heard where anyone took an engine apart based on oil analysis findings.

It all depends on your vantage point is. For me and my view this is a common route especially on the commercial side and the turbine or helicopter side. When it comes to Part 91 GA a lot of the proven preventative measures are not used on over 50% of the aircraft simply due to cost or the owner not understanding the benefit. And a certain percentage of those who do use those methods do not understand how they work or what to expect. So you get a scenario of where someone checks his filter after a bad oil report. What's the point.

 

[Gary Ward]

I sent in a sample to AvLabs about 6 months ago and have heard nothing. I tried to call them and sent emails with no luck. My old results are still on their website but I expect it to eventually 404...

I would suspect to post office is the hold up?
Our local postal service is down to delivery 2-3 days a week.
It is taking 2.5 weeks to receive business checks that are mailed from the other side of town.
If you want fast then I would use UPS, Fedex etc other than the post office.

 

[Gary Ward]

I’ve wondered about how this may affect a sale. What if it’s the other way around? Let’s say the engine has a higher than normal lab trend. Do you advise the potential buyer of a poor lab report if all other traditional indicators are normal? This info is tracked by SN and registration, so there’s a record. Could this hurt the sale?
On the other hand, if all the lab history is great it’s obviously a benefit.
I did a prebuy for a POA member a couple years ago. The oil analysis was consistently normal for past 15 years SMOH. Wasn’t long after the purchase that we found a number of internal engine components coming apart. Zero warning. We were ultimately able to get everything taken care of without splitting the case.

I do all my own service to my plane myself with supervision from my IA mechanic. I want to demonstrate to anyone outside that I am not cutting corners and the plane is getting the best service possible.
Like I said I may fly the engine until TBO myself then it won't matter but at least I will have a good handle on it's health until I overhaul or replace it.
Yea it is a feel good experience to read these kinds of reports and would suck if it was the other way around. But wouldn't you want to know if something is not right in your engine? It is your butt in the seat.

 

[Gary Ward]

Here is my last report for my old engine after I re assembled all 4 cylinders. The reason I post this is because of the silicon numbers. They are high but not because of poor air filtration. I run a Challenger re usable filter that I keep clean and my other reports above show low silicon numbers indicating good air filtration. My theory which was shared with me by another member is when you install new silicon valve cover gaskets it causes your reading to be higher at first. Sure enough as the hours go by the silicon numbers came down even with a dirtier air filter. I installed new valve cover gaskets on my old engine and the readings were high at first. Same thing from my factory lycoming engine, it came with silicon valve cover gaskets and the readings were high even with freshly cleaned air filter, then they came down and I did more oil changes.
This was the last report for this engine before I sent it back to lycoming as a core, so I ran the oil and filter to 98 hrs. Didn't seem to hurt anything? I have never used a drop of silicon sealer anywhere on my aircraft engines, so the silicon readings did not come from sealers. But I did use plenty of WD40 on the cly walls and piston rings during assembly so that may have have come into play here?