oil analysis after top overhaul

Jon Gunther

Jon Gunther

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Jon Gunther
Hello all, about 25 hours ago we did a top overhaul on my 0-320-e2a. My question is, should we do an oil analysis on the break in oil, or wait till we switch back to the normal oil?
 
I'm waiting on mine...I have bout 30 hrs on a top and one oil change. I might do one after the next oil change.
 
Do it. Ain’t gonna cost that much. Lab should be able to tell you how your oil compares to the limits for top break-in. That and the filter cut should make you more confident that just normal wear is occurring.
 
I would love to hear from anyone who does oil analysis and actually made the decision to tear a recently overhauled or low time engine apart on the basis of the oil sample lab results. Anyone?

Let's suppose the lab comes back and tells the OP its NOT within limits for a top break-in (assuming they actually have an objective way of determining that). What's the owner going to do, having paid for the analysis? Tear off the new cylinders? Sue the shop that did the top? Something else?
Most likely going to get in the plane and fly it some more and see what happens, all the time with a little anxiety gnawing away inside. Until the next oil change and the next oil analysis. Or the one after that. Or the one after...

I am a believer in spending money to get data that allows me to take more decisive actions. I am yet to be convinced the money spent on oil analyses adds any value in that respect.

But then, I don't wear one of those health monitoring watches either. So what do I know...
 
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the analysis is great for resale....people like it and will spend extra. ;)
 
@GRG55 you have a point there.

For me, it’s a little like glancing down at the engine instruments and confirming “green”. When it’s green, no biggie. When it’s not - hmmm, wtf is going on? Then what? Heck, I dunno; Land? Keep going? Check later? Ignore it?

It’s cheap voodoo maybe. I’m not not gonna do it, lol.
 
Checkout_my_Six said:
I'm waiting on mine...I have bout 30 hrs on a top and one oil change. I might do one after the next oil change.
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30 hours since a top overhaul oil change? I had to replace one cylinder and did an oil change after 10 hours and was told to do one again after another 10 hours.

I do an oil analysis after every oil change it not for the oil changes after the new cylinder. For me the purpose of an oil analysis is to show a trend.
 
455 Bravo Uniform said:
@GRG55 you have a point there.

For me, it’s a little like glancing down at the engine instruments and confirming “green”. When it’s green, no biggie. When it’s not - hmmm, wtf is going on? Then what? Heck, I dunno; Land? Keep going? Check later? Ignore it?

It’s cheap voodoo maybe. I’m not not gonna do it, lol.
Click to expand...

I've heard the argument that airplane engines are expensive (can't disagree with that), and more information about the health of the engine is useful, especially since oil analysis is comparatively inexpensive (unlike so many other things on an airplane).

There's a difference between an engine instrument indication and an oil analysis indication. With the former when the pilot makes a change to try to address the "outside of green" (such as richen the mixture, open the cowl flaps, change the MP/RPM, turn on the boost pump, change the fuel tank, etc) there's a rapid feedback from the gauge as to whether an action has had a positive, negative or zero effect, and that inputs into the subsequent decisions being made real time to resolve the anomaly.

I've just never understood what an owner is going to do with an oil analysis, or even a string of them trending, "outside of green"? Especially if there is not (yet) any other indication of a problem.
 
I had a bad camshaft, oil analysis was normal, no metal in filter, the engine monitor let me know it was bad.


Tom
 
Jamie Kirk said:
30 hours since a top overhaul oil change? I had to replace one cylinder and did an oil change after 10 hours and was told to do one again after another 10 hours.

I do an oil analysis after every oil change it not for the oil changes after the new cylinder. For me the purpose of an oil analysis is to show a trend.
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I did a change after 5 hrs....and now up to 30 hrs. since Top.
 
MooneyDriver78 said:
I had a bad camshaft, oil analysis was normal, no metal in filter, the engine monitor let me know it was bad.


Tom
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yup....oil analysis only indicates fine...."fine"..."PPM sized" ....particulate wear. Course wear debris will not indicate with oil analysis. The medium sized material/debris is found in the oil filter....and larger in the oil screen/pan.
 
I would if for nothing else having data that correlates to the break in wear just out of curiosity. Smarter people than I am will be along at some point.
 
Checkout_my_Six said:
yup....oil analysis only indicates fine...."fine"..."PPM sized" ....particulate wear.
Click to expand...

But only if it’s a rapid wear, slow wear you won’t notice. So if you do what’s best for an engine (frequent flights and oil changes) you won’t get a large elevation of the levels of iron.


Tom
 
MooneyDriver78 said:
But only if it’s a rapid wear, slow wear you won’t notice. So if you do what’s best for an engine (frequent flights and oil changes) you won’t get a large elevation of the levels of iron.


Tom
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I'm not gonna get iron wear anyways.....mine are Nickel coated.
 
GRG55 said:
I would love to hear from anyone who does oil analysis and actually made the decision to tear a recently overhauled or low time engine apart on the basis of the oil sample lab results. Anyone?

Let's suppose the lab comes back and tells the OP its NOT within limits for a top break-in (assuming they actually have an objective way of determining that). What's the owner going to do, having paid for the analysis? Tear off the new cylinders? Sue the shop that did the top? Something else?
Most likely going to get in the plane and fly it some more and see what happens, all the time with a little anxiety gnawing away inside. Until the next oil change and the next oil analysis. Or the one after that. Or the one after...

I am a believer in spending money to get data that allows me to take more decisive actions. I am yet to be convinced the money spent on oil analyses adds any value in that respect.

But then, I don't wear one of those health monitoring watches either. So what do I know...
Click to expand...

GRG55 said:
I've heard the argument that airplane engines are expensive (can't disagree with that), and more information about the health of the engine is useful, especially since oil analysis is comparatively inexpensive (unlike so many other things on an airplane).
*snip*

I've just never understood what an owner is going to do with an oil analysis, or even a string of them trending, "outside of green"? Especially if there is not (yet) any other indication of a problem.
Click to expand...

You're both absolutely right. I've never heard of oil analysis providing anything other than confirmation of what an owner already knew, or confusion. "More data" is only good if it's reliable, meaningful, and actionable. Oil analysis almost never fits that definition.
 
I'm thinking the first analysis might be full of normal crud as the new cylinders settle in.
(I prefer to change the oil at 5-10hrs after cylinder change for that reason, then 25-30hrs later.)

However, for your question...

I like to think I make efforts to look ahead.

So, in this case I might say; Let's presume there is a problem with the second analysis.
With that presumption, would you then say "I wish I knew what was going on with the first analysis." Maybe it would not be particularly helpful in this case, but that is how I approach things.
 
Cap'n Jack said:
Or aren't an iron alloy.
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Once upon a time way long time a go R/R had an engine that had carbide rings and tungsten cylinders.. or maybe it was the other way around, anyway the cost of manufacture was unrealistic for production.
so there may be something weird out there. but I doubt anyone is flying it.
 
Back in the old days (yes, I was around then) it became popular to use chrome rings in automotive engine rebuilds. It gave you a free rebore for the next oversize at the next rebuild.( a joke) Not a good plan. It led to improvement in cast iron rings with a moly fill. Cast iron rings are the only way to go.

It is against conventional wisdom, but in the seventies, Ryder Labs proved that cast iron rings would seat on a glazed cylinder that was within dimensional limits, but I digress.
 
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MBDiagMan said:
Back in the old days (yes, I was around then) it became popular to use chrome rings in automotive engine rebuilds. It gave you a free rebore for the next oversize at the next rebuild.( a joke) Not a good plan. It led to improvement in cast iron rings with a moly fill. Cast iron rings are the only way to go.

It is against conventional wisdom, but in the seventies, Ryder Labs proved that cast iron rings would seat on a glazed cylinder that was within dimensional limits, but I digress.
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Solid chrome, or chrome faced? I also saw where stainless steel rings could be used (hence my iron alloy comment, those could still shed iron as @Tom-D was alluding).

https://www.hastingspistonrings.com...s-piston-ring-set-composition-recommendations
 
Funny,,,, Stainless Steel, is Still steel.
 
Checkout_my_Six said:
but....not iron. :D
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Yes IRON. major ingredient is iron. most Stainless has less than 10% chrome or nickle.

Break it down by chemical in the oil analysis it will show as each ingredient ( IRON )

None of the rings you can buy are stainless, they are at best cast iron with the top ring being chrome plated on the surface that touches the cylinder wall.
 
Tom-D said:
Yes IRON. major ingredient is iron. most Stainless has less than 10% chrome or nickle.

Break it down by chemical in the oil analysis it will show as each ingredient ( IRON )

None of the rings you can buy are stainless, they are at best cast iron with the top ring being chrome plated on the surface that touches the cylinder wall.
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what chemicals are in iron? :D
 
Tom-D said:
Did you forget? Iron has its own chemical number and Chemical abbreviation ?

https://en.wikipedia.org/wiki/Iron
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Tom- it's an atomic number, based on the number of protons in its nucleus. The closest thing I can recall being a "chemical number" is a "chemical abstracts number" (CAS number), used to uniquely identify a substance.

Checkout_my_Six said:
maybe you forgot what a chemical is ....Tom? :D

Fe....is not a chemical. It's an element....or mineral. When mixed with other elements it forms compounds....which are referred to as "chemical" compounds.
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I actually consider iron to be a chemical, even it its elemental form. I can use it for reactions, like any other chemical. Another term is "chemical element" for elements such as pure iron, hydrogen, oxygen, chlorine, iodine, etc
 
Checkout_my_Six said:
maybe you forgot what a chemical is ....Tom? :D

Fe....is not a chemical. It's an element....or mineral. When mixed with other elements it forms compounds....which are referred to as "chemical" compounds.
Click to expand...

OK element, what will the oil analysis sheet list? Or are we back to the same old question?

Now you've discovered how to make steel.

Good for you :)
 
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