Oil Analysis - good read

[svfinlandia]

Originally Posted by robert sailor

Oil analysis is good but you need a good baseline to start with and then a few samples at specific times for the analysis to be worth anything. The longer you take them the better information you will get.

My point exactly. As someone else said earlier, one oil sample doesn’t tell you very much.

Al, S/V Finlandia

[a64pilot]

If you guys feel an oil analysis will spot upcoming problems, knock yourselves out.
I’ve never seen it, and I maintained fleets of helicopters that had regular oil analysis done on the components, the nose gearboxes for example the sample interval was every 25 hours.
Also all our trucks were having oil analysis’s done, to determine oil change intervals, for that it’s excellent, an oil analysis is excellent for determining the condition of the oil, that is after all what it is, but for determining the conditioning of an engine? It’s next to worthless.

The theory is that when an engine begins to “make metal” an oil analysis will catch it in time as you will see a spike in a certain type of metal, they type of metal will tell you the source of the metal, bearing material and rings are of course very different metals.

The guy who’s engine threw a rod, would someone please tell me how an oil analysis would have predicted that?
About the only way is if the bearing slowly wore out before it spun, then maybe the higher metal content of the oil would have someone tear an engine apart to investigate.

You know how many engines I’ve seen taken apart or removed from service based on an oil analysis? Exactly zero, no oil analysis report will ever say, engine failure imminent, remove engine from service, none.
What they will say is change oil, resample at 25 hours and send in another oil sample, cause I’ve seen that many, many times.

If you really want to spot impending engine failure, instrument your engine, know it’s oil pressure and temp, buy an oil filter cutter and learn how to inspect the filter media, cause if an engine is actually making metal, where do you think it ends up?

You use your cutter to remove the can from the filter, you look for metal, if any is found you test it with a magnet to see if it’s ferrous metal or not, and you cut the media, wash it with mineral spirits and filter the mineral spirits to collect the metal.

But, and this is the big BUT, engines rarely make metal for very long before they go bang, and always when they do you get other indicators, like low oil pressure and high oil temps.

Since you guys like Blackstone labs and they are a very good lab, I’ll link to their how to page. Now it’s pretty aircraft engine specific, but it can also of course be used for any engine the principles are the same.
https://www.blackstone-labs.com/wp-c...Newsletter.pdf

Just noticed Blackstone reprinted John of Sacramento’s sky ranch’s article, but that if anything adds legitimacy to it in my opinion.

[mvweebles]

Originally Posted by b_rodwell

So would you guys recommend an oil test any time you are considering buying a used boat? (Obviously that would not work if the oil had just been changed)

Yes, absolutely (engine, transmission, and generator if equipped). As others have noted, better to have a trend, but if you read the Steve D article carefully, you will find that there are certain markers such as sodium (sea water) and certain alloys found only in bearings that should not be present in the oil in any concentration. So if you discover any discernible amount, it gives a clue. As far as masking results with a recent oil change, well, that can be a problem. Often times, the engine hours are marked on the oil filter in sharpie. Or the owner may have logs. Both could be faked, but it's at least something. Finally, long sea trials are not the norm, but you can always ask for an extended sea trial of at least 5-6 hours. When you send the oil sample in, it helps the lab to know how many hours on the sample so they can equilibrate for the engine hours. Not ideal, but again, better than nothing. And you'll have a baseline for future use.

A couple best-practices on oil analysis - rather than doing it every year, do it at regular engine-hour intervals, which may coincide with oil changes. Every 100 or 200 hours. Whatever you do. Lab may also ask how much make-up oil you've added during the period, so keep track of that too. Finally, as stated in the Steve D article, best to pull the oil when it's hot and hasn't set long enough for the particulates (if any) to settle.

Finally, here's a YouTube from a Midwest guy who does all sorts of mechanical tests (I've watched him blow-up dozens of lawnmower engines testing if Slick 50 actually works, etc.). This video compares a 70-year old can of Quaker State to modern engine oil. If you skip to 9:55, he shows a commercial engine oil analysis and describes the interpretation. Also note the "TBN" number which was also noted in the Steve D article as the oil's tendency to acidify.

https://www.youtube.com/watch?v=-zHlxeu_yuM

As a footnote, at $40/test (or less), it's great info. As mentioned, I posted this thread based on another CF thread where a 50-foot Beneteau threw a connecting rod, probably due to an exhaust water leak over time. There's a decent chance doing regular engine oil tests would discover sodium in the oil well before it caused a catastrophic failure. $40/test vs $12k engine replacement (guess). I've gotten lazy about tests over the years, and will definitely be more vigilant.

To the post saying it's common on airplanes but not on boats, not so - very common among the cruising-trawler crowd, especially those with larger engines. Catastrophic failures can easily reach $30k in repairs.

[mvweebles]

Originally Posted by a64pilot

The guy who’s engine threw a rod, would someone please tell me how an oil analysis would have predicted that?

How would an oil analysis help alert an impending issue that could result in a thrown con-rod? Easy. Chances are excellent the issue started with salt water intrusion into the exhaust. Most likely a poorly designed exhaust system, or, since mixing elbows rust from the inside-out, from a worn elbow. Would start with a drip or two, and slowly get worse. There's a damn good chance regular oil analysis would pick-up the sodium in the oil. Or, if the lower end bearing is wearing due to some sort of elongation or install mistake, oil analysis would pick-up the alloy metals.

Another example where an oil analysis would predict failure before major issues: Glycol should not be present in oil in any concentration. If you see it, it's from your coolant system, most likely a head gasket. If the head gasket blows completely all at once, well, oil test wouldn't give you a heads-up, but often it's a slow leak that's difficult to isolate otherwise.

Excessive carbon in oil is indicative of blow-by, or worn rings (trend is best on this).

And yes, for fleet management, it's helpful to test for TBN to determine when an oil change is needed. Not practical for small boats, but that's another use.

Here's another Steve D article on exhaust system design.

http://www.oceannavigator.com/May-Ju...system-design/

[a64pilot]

If You have an oil analysis ever 25 hours like we did on the helicopter, then maybe.
But most of you guys seem to run 200 hours or more between oil changes.
Do you really think these issues that cause engine failures take hundreds of hours to slowly occur, head gaskets for example do you think they slowly blow over hundreds of hours, or a exhaust elbow, takes hundreds of hours for one to go from slow leak to big leak?

So like I said if you think getting your oil analyzed once a year or so is going discover latent failures, do so.
But I can assure you, that if it did, then oil analysis would be mandatory for aircraft engines, and it’s not, not by the FAA anyway. Inspecting oil filters is.

On edit, your way better off adopting an inspection/replacement interval for your exhaust elbow, and there are inexpensive kits if your worried about a slowly blowing head gasket that will detect exhaust gasses in your coolant, but disappearing coolant levels ought to be your first clue there.
Relying on a once a year or so oil analysis to detect either before engine damage is, well just hoping, it’s not a good plan.

Then I don’t know about you, but I’m away from home base when we are cruising, I’ve not tried mailing anything, but I know how hard it is to get something sent to me.

Oil analysis is an industry that I’m sure makes some people millions of dollars, just I have never, ever seen it’s worth for engine analysis and I have decades of experience with it.
It has saved the taxpayer Millions I’m sure and probably saved the environment because since at least the early 80’s Military vehicles oil changes are based on oil condition, not calendar or hours.
It’s great for analyzing oil, like you said for finding antifreeze or excess dirt etc. but not for detecting imminent engine problems, or oil lubricated rotating components.
There are grease analysis as well, I’ve seen the main rotor swashplate on the AH-1 have grease analysis’s done after the change over to the new Kaman 747 rotor blades, and several aircrews killed from swasholate failures, but never seen a Swashplate condemned by grease analysis.

[mvweebles]

Originally Posted by a64pilot

If You have an oil analysis ever 25 hours like we did on the helicopter, then maybe.
But most of you guys seem to run 200 hours or more between oil changes.
Do you really think these issues that cause engine failures take hundreds of hours to slowly occur, head gaskets for example do you think they slowly blow over hundreds of hours, or a exhaust elbow, takes hundreds of hours for one to go from slow leak to big leak?

So like I said if you think getting your oil analyzed once a year or so is going discover latent failures, do so.
But I can assure you, that if it did, then oil analysis would be mandatory for aircraft engines, and it’s not, not by the FAA anyway. Inspecting oil filters is.

On edit, your way better off adopting an inspection/replacement interval for your exhaust elbow, and there are inexpensive kits if your worried about a slowly blowing head gasket that will detect exhaust gasses in your coolant, but disappearing coolant levels ought to be your first clue there.
Relying on a once a year or so oil analysis to detect either before engine damage is, well just hoping, it’s not a good plan.

Then I don’t know about you, but I’m away from home base when we are cruising, I’ve not tried mailing anything, but I know how hard it is to get something sent to me.

Oil analysis is an industry that I’m sure makes some people millions of dollars, just I have never, ever seen it’s worth for engine analysis and I have decades of experience with it.
It has saved the taxpayer Millions I’m sure and probably saved the environment because since at least the early 80’s Military vehicles oil changes are based on oil condition, not calendar or hours.
It’s great for analyzing oil, like you said for finding antifreeze or excess dirt etc. but not for detecting imminent engine problems, or oil lubricated rotating components.
There are grease analysis as well, I’ve seen the main rotor swashplate on the AH-1 have grease analysis’s done after the change over to the new Kaman 747 rotor blades, and several aircrews killed from swasholate failures, but never seen a Swashplate condemned by grease analysis.

A64pilot. I respect many of your posts. But in 25 years of boating, a fair amount of it as a full-time delivery skipper, you are the first person I've encountered who totally disses oil analysis. Most knowledgeable people caution against single samples without a trend. But you are the first who dismisses the information entirely.

[Wotname]

Originally Posted by mvweebles

A64pilot. I respect many of your posts. But in 25 years of boating, a fair amount of it as a full-time delivery skipper, you are the first person I've encountered who totally disses oil analysis. Most knowledgeable people caution against single samples without a trend. But you are the first who dismisses the information entirely.

I don't have an oar in this dinghy but I am always interested in engine maintenance techniques.

It seems to me that pertinent question is how many times has an oil analysis trend led to the discovery of impending engine failure as confirmed by a tear down of the engine before a terminal failure and seen the worn parts that oil analysis trend had predicted?

If occasionally, then the oil analysis is worth if but if never, then the oil analysis doesn't help regardless of what people believe about it.

[mvweebles]

Originally Posted by Wotname

I don't have an oar in this dinghy but I am always interested in engine maintenance techniques.

It seems to me that pertinent question is how many times has an oil analysis trend led to the discovery of impending engine failure as confirmed by a tear down of the engine before a terminal failure and seen the worn parts that oil analysis trend had predicted?

If occasionally, then the oil analysis is worth if but if never, then the oil analysis doesn't help regardless of what people believe about it.

It's the right question - does an oil analysis give meaningful data that can be actioned. Unfortunately, it's proving a negative - the theory is that by identifying a small problem now you prevent a large problem later. I am conformable saying that you have a much greater chance of identifying salt water intrusion or advanced bearing wear via an engine oil analysis than through any other method as there are none.

I agree with A64 in some ways - if the fault initiates immediately after the oil analysis, the issue may cause failure before the next change. But given the modest cost of the analysis and the hi cost and inconvenience of a failure, this one is a no-brainer for me.

[a64pilot]

Originally Posted by mvweebles

A64pilot. I respect many of your posts. But in 25 years of boating, a fair amount of it as a full-time delivery skipper, you are the first person I've encountered who totally disses oil analysis. Most knowledgeable people caution against single samples without a trend. But you are the first who dismisses the information entirely.

I spent 15 years as a Maintenance Pilot, we didn’t have the engines on oil analysis as GE said it was useless.
But we did have the nose gearboxes, the main transmissions and the APU on an analysis program, the ARMY has its own oil labs at each major installation. They were very much cutting edge, I’ve visited them.
We called it SOAP or Spectroscopic Oil Analysis Program. You sent in a sample that was meticulously taken usually by an analysis tube right after shutdown, the oil was analyzed through different processes, the one that determined any metals was a machine that spun a carbon disk that picked up the oil that was then burned and what was burned was spectroscopically analyzed.
Different processes measured viscosity and other test that I honestly don’t remember.

I’m not so much really against it, it doesn’t hurt and if it gives you a good feeling, go ahead.
What I am against is the people who want to line up and tell you all these things it will do, that it won’t do.

Now as I said if you get in a regular analysis program with a sample interval of every 25 hours or so, then maybe it will give you useful info, maybe. I’ve never seen it, but I’ve not seen everything.
But so far as I’ll send in a sample every couple of years or every 250 hours when I do an oil change, forget it.

So far as making metal, when engines start that, it goes very rapidly. Cams wear out and make metal when the super hard, but very thin surface wears off, then a lobe rounds off very quickly, as in a few hours.
Main and rod bearings wear very slowly and one day when the clearance is excess to the point that there is room for one to spin, it does, and very, very soon the engine seizes, or begins to knock so loud you shut it down, or it throws a rod, the failure is sudden, but for years leading up to it there has been a slow decrease in oil pressure as clearances open up and pressure can’t be maintained. The oil pressure is you sign, not an oil analysis.
Or a bearing is oil starved, seizes and spins, that is a very sudden failure.

It’s like a lot of things. You get something that isn’t a bad idea, but some make money out of it, and many, many jump on the band wagon to be so called experts. I’ve been astonished how many, apparently we’ll respected experts there are, and what amounts or complete nonsense they publish, and how so many will read it, and take it as gospel.
Let’s sell a super expensive high power generator to run off of the engines crankshaft, control it with electronics and convince people they don’t need a separate generator.
But let’s not tell them that Yanmar’s published max allowable power to extract from that engine at normal cruise is 4 HP, which is 100 amps at 12V.

Or High TBN oil will ruin your engines for one, beware of high TBN oil.
Such utter nonsense, we are to believe that a major super respected oil company like Shell is selling oil that will ruin engines, and all the major manufacturers from Caterpillar, John Deere and Yanmar etc approve of their oil, but don’t run it, cause if you do it will glaze your cylinder walls.
Where are all these engines that have been ruined by high TBN oil at anyway?

But let’s ignore that fact that since the mandate of ULSD that high TBN oil simply isn’t available, except rarely for apparently ship engines and maybe Locomotives etc. that need it because they burn very high sulphur fuel.

But what really bothers me is that there are procedures and inspections that will in fact work, been working for decades, but they require some training, and some work.
But people don’t want that, they want the newest latest high tech wizardry, that just spend some bucks on, no work, no training.
Problem is the proponents of the Wizardry have way out sold it’s uses.
It’s not a bad tool but it’s not capable of all the things people try to sell you on.

Funny thing is, if you go to a mechanics convention etc and talk to the Blackstone people, they don’t blow smoke up your behind, they tell it like it is.

Bottom line, it doesn’t hurt, except for the cost, but don’t rely on it to find anything truly, your much better off with a little training, cutting open and inspecting filters yourself and engine instrumentation, and knowing what it’s telling you.
If you do all of that and for an abundance of caution want to have an oil analysis, sure why not.
However I see people not doing those other things because they believe oil analysis makes it unnecessary, and I believe that to be incorrect.

Now I’m not the old guy that only wants to work on his Grandfathers engines, I love modern, electronically controlled engines, so long as there is an OBDII type of system, and it’s available to the user, and not only to dealers etc. So I embrace modern inventions, but I’ve never, ever seen oil analysis catch a component prior to their being other indications like high oil temp. Or in aircraft a chip light

[rbk]

So if you had an iron block and during regular analysis you suddenly see a spike in non ferrous content you would say that means nothing? No thrust bearing wear no anti-friction bearing nothing? Or as other mentioned small amounts of salt, fuel etc? There’s always the possibility something fails between inspection or regular maintenance that’s just the way things happen sometimes. Im no expert but maybe. We shouldn’t be comparing aviation engines to boat diesels. I would agree that component failure in an aircraft engine would be almost immediate but in a small diesel chugging along at <2k rpm? I think they have a bit more appetite for punishment, no? Just so there may no misinterpretation as there always seems to be online, I am honestly curious as I have passed on several boats for some of these reasons based on recommendations on analysis from very qualified marine mechanics on the above basis.

[mvweebles]

Originally Posted by a64pilot

I spent 15 years as a Maintenance Pilot, we didn’t have the engines on oil analysis as GE said it was useless.
But we did have the nose gearboxes, the main transmissions and the APU on an analysis program, the ARMY has its own oil labs at each major installation. They were very much cutting edge, I’ve visited them.
We called it SOAP or Spectroscopic Oil Analysis Program. You sent in a sample that was meticulously taken usually by an analysis tube right after shutdown, the oil was analyzed through different processes, the one that determined any metals was a machine that spun a carbon disk that picked up the oil that was then burned and what was burned was spectroscopically analyzed.
Different processes measured viscosity and other test that I honestly don’t remember.

I’m not so much really against it, it doesn’t hurt and if it gives you a good feeling, go ahead.
What I am against is the people who want to line up and tell you all these things it will do, that it won’t do.

Now as I said if you get in a regular analysis program with a sample interval of every 25 hours or so, then maybe it will give you useful info, maybe. I’ve never seen it, but I’ve not seen everything.
But so far as I’ll send in a sample every couple of years or every 250 hours when I do an oil change, forget it.

So far as making metal, when engines start that, it goes very rapidly. Cams wear out and make metal when the super hard, but very thin surface wears off, then a lobe rounds off very quickly, as in a few hours.
Main and rod bearings wear very slowly and one day when the clearance is excess to the point that there is room for one to spin, it does, and very, very soon the engine seizes, or begins to knock so loud you shut it down, or it throws a rod, the failure is sudden, but for years leading up to it there has been a slow decrease in oil pressure as clearances open up and pressure can’t be maintained. The oil pressure is you sign, not an oil analysis.
Or a bearing is oil starved, seizes and spins, that is a very sudden failure.

It’s like a lot of things. You get something that isn’t a bad idea, but some make money out of it, and many, many jump on the band wagon to be so called experts. I’ve been astonished how many, apparently we’ll respected experts there are, and what amounts or complete nonsense they publish, and how so many will read it, and take it as gospel.
Let’s sell a super expensive high power generator to run off of the engines crankshaft, control it with electronics and convince people they don’t need a separate generator.
But let’s not tell them that Yanmar’s published max allowable power to extract from that engine at normal cruise is 4 HP, which is 100 amps at 12V.

Or High TBN oil will ruin your engines for one, beware of high TBN oil.
Such utter nonsense, we are to believe that a major super respected oil company like Shell is selling oil that will ruin engines, and all the major manufacturers from Caterpillar, John Deere and Yanmar etc approve of their oil, but don’t run it, cause if you do it will glaze your cylinder walls.
Where are all these engines that have been ruined by high TBN oil at anyway?

But let’s ignore that fact that since the mandate of ULSD that high TBN oil simply isn’t available, except rarely for apparently ship engines and maybe Locomotives etc. that need it because they burn very high sulphur fuel.

But what really bothers me is that there are procedures and inspections that will in fact work, been working for decades, but they require some training, and some work.
But people don’t want that, they want the newest latest high tech wizardry, that just spend some bucks on, no work, no training.
Problem is the proponents of the Wizardry have way out sold it’s uses.
It’s not a bad tool but it’s not capable of all the things people try to sell you on.

Funny thing is, if you go to a mechanics convention etc and talk to the Blackstone people, they don’t blow smoke up your behind, they tell it like it is.

Bottom line, it doesn’t hurt, except for the cost, but don’t rely on it to find anything truly, your much better off with a little training, cutting open and inspecting filters yourself and engine instrumentation, and knowing what it’s telling you.
Of you do all of that and for an abundance of caution want to have an oil analysis, sure why not.
However I see people not doing those other things because they believe oil analysis makes it unnecessary, and I believe that to be incorrect.

You're comparing a very heavy cast iron marine diesel engine - a slow turning compression igniting engine - to a lightweight aircraft engine. With proper maintenance, Marine Diesels in our classification/rating often go 10,000 hours before rebuild. Small aircraft engines are specified at something under 2000 hours.

Would be difficult to find two more polar opposite engines to compare a single test.

Don't test your oil. Fine by me. Personally, I have confidence in Steve D'Antonio and a few diesel mechanics I've gotten to know over the years who view test data with extreme interest.

Look at it this way: if I had a new mechanic aboard and I told him "hey, I have been having my oil analyzed - would it help you diagnose my rough-idle problem?" and he said "Bullcrap. I don't need no stinking oil analysis!" I'd toss him off my boat.

[a64pilot]

Not to be a smart arse, but engine mechanic wise, I am an expert, card carrying, licensed for decades

Boat Diesels, lawnmowers etc. the interval between making metal and failure is short, if its from something that will cause a failure. Metal is not always death, but often is.
It could be from a thrust washer on a rocker arm, usually isn’t, but it could be.

Some transmission types of devices, not so much, if your a mechanic, we have all drained a rear end or boat outboard foot that had glitter in the oil, yet the rear end lasts for quite some time, or not.
If it’s something that I rely on, if I drain the oil and get glitter, I’m overhauling the part.
Cheap lawnmower? I’ll run it until it blows.
I’ve blown up motors, but in my life, I have only worn out one, that was when I was a kid cutting firewood, I wore a Poulan 361 bow saw, slap out, the chrome came off of the cylinder wall and it was done.

[a64pilot]

Originally Posted by mvweebles

You're comparing a very heavy cast iron marine diesel engine - a slow turning compression igniting engine - to a lightweight aircraft engine. With proper maintenance, Marine Diesels in our classification/rating often go 10,000 hours before rebuild. Small aircraft engines are specified at something under 2000 hours.

Would be difficult to find two more polar opposite engines to compare a single test.

Don't test your oil. Fine by me. Personally, I have confidence in Steve D'Antonio and a few diesel mechanics I've gotten to know over the years who view test data with extreme interest.

Look at it this way: if I had a new mechanic aboard and I told him "hey, I have been having my oil analyzed - would it help you diagnose my rough-idle problem?" and he said "Bullcrap. I don't need no stinking oil analysis!" I'd toss him off my boat.

You think oil analysis will find the cause of a rough idle?
That is exactly my point, you made it well.

Actually I wasn’t comparing aircraft engines, actually the transmissions, since GE said oil analysis of the T-701 engine was of no value, we didn’t sample them.

[mvweebles]

Originally Posted by a64pilot

Not to be a smart arse, but engine mechanic wise, I am an expert, card carrying, licensed for decades

Boat Diesels, lawnmowers etc. the interval between making metal and failure is short, if its from something that will cause a failure. Metal is not always death, but often is.
It could be from a thrust washer on a rocker arm, usually isn’t, but it could be.

Some transmission types of devices, not so much, if your a mechanic, we have all drained a rear end or boat outboard foot that had glitter in the oil, yet the rear end lasts for quite some time, or not.
If it’s something that I rely on, if I drain the oil and get glitter, I’m overhauling the part.
Cheap lawnmower? I’ll run it until it blows.
I’ve blown up motors, but in my life, I have only worn out one, that was when I was a kid cutting firewood, I wore a Poulan 361 bow saw, slap out, the chrome came off of the cylinder wall and it was done.

Do what you want. For the others who read threads like this and do not consider themselves a self professed mechanical expert, please consider having your oil tested. It may not be perfect, but it is some of the best data you can ascertain to foresee potential engine failure conditions. It's the rough equivalent of having your blood pressure checked, PSA test, or the myriad of other diagnostic tests run to see if there are anomalies. Goal is to discover a condition before it advances. An engine oil test - at no more than $40 - is your best chance of discovery. Yes, just like health checks, a baseline and trend line is most informative, but that doesn't mean a single data point is worthless.

Please, read the Steve D article and others like it from industry experts and make up your own mind. Cost is low. Benefit is high.

[mvweebles]

Originally Posted by a64pilot

You think oil analysis will find the cause of a rough idle?
That is exactly my point, you made it well.

Actually I wasn’t comparing aircraft engines, actually the transmissions, since GE said oil analysis of the T-701 engine was of no value, we didn’t sample them.

My sense is you will argue with anything. Anyone who would ignore data points is someone who has made up their mind too early. I'm sure it's worked for you, but it's not the person I want working on my boat. You never know what you might learn if you look around with a fresh set of eyes.