How Realistic Is This Theory?

Status
Not open for further replies.
Thanks ed, that's a nice summary and makes good sense. So they use atomic emission spectroscopy in the UOA industry, and what is this limitation that's often mentioned then with these analyses? Is only on particles above a certain size and if so is it that large particles ie sparklies tend to fall out of the sample before it's even introduced to the plasma or that they remain agglomerated in the plasma or some other mechanism?
 
Found the answer. For anyone curious it's some basic stuff from MachineryLubrication

Quote:
Influence of Particle Size
The major limitation with AES is that because the method requires excitation of individual atoms, the sample must be fully vaporized to allow all atoms present to be measured. While this is not a problem for small particles and dissolved metals, the probability that a particle can be vaporized and analyzed using AES drops very rapidly above 5 microns. In fact an AES spectrometer is all but blind to particles in excess of 10 microns.

Unfortunately, depending on the wear mechanism and the severity of the problem, active machine wear may generate particles that are greater than 10 microns in size, and will thus be invisible to the AES instrument. For this reason, it is important in any oil analysis program to not rely solely on AES data to determine active wear, but to include tests such as particle counting, ferrous density analysis and patch microscopy to measure larger particles.
 
Originally Posted By: PeterPolyol
Thanks ed, that's a nice summary and makes good sense. So they use atomic emission spectroscopy in the UOA industry, and what is this limitation that's often mentioned then with these analyses? Is only on particles above a certain size and if so is it that large particles ie sparklies tend to fall out of the sample before it's even introduced to the plasma or that they remain agglomerated in the plasma or some other mechanism?


The sample induction system is specifically designed to reject droplets greater than about 4.5 microns as larger ones destabilize the plasma. Since the droplets are carried into the plasma by argon flow, that diameter is aerodynamic diameter. I discussed this in detail in the second half of post #4147917 of this thread.

Ed
 
Well as you see, aluminium particles are likely the biggest ones that can be measured in a UOA, and titanium particles will already be smaller. Iron/chromium will be smaller yet and then we get copper. Lead particles detected will be the smallest, and all will be smaller than 4µm.

Normal oil filters will not filter any of the measurable particles out. Bypass filters can, however.
 
This "theory" is a b.s. New oil is always better than used (contaminated) one - new additive pack, no fuel contamination, no oxidation thickening going out of grade... I think said "theory" must be invention of people who try to find excuses for not changing the oil in their cars or people obsessed with the idea of saving new oils and depositing less used ones (which is a good thing, but not for your engine.
 
Originally Posted By: Thebimmerfan
This "theory" is a b.s. New oil is always better than used (contaminated) one - new additive pack, no fuel contamination, no oxidation thickening going out of grade... I think said "theory" must be invention of people who try to find excuses for not changing the oil in their cars or people obsessed with the idea of saving new oils and depositing less used ones (which is a good thing, but not for your engine.


What on earth are BMW thinking then ?
 
Originally Posted By: Shannow
Originally Posted By: Thebimmerfan
This "theory" is a b.s. New oil is always better than used (contaminated) one - new additive pack, no fuel contamination, no oxidation thickening going out of grade... I think said "theory" must be invention of people who try to find excuses for not changing the oil in their cars or people obsessed with the idea of saving new oils and depositing less used ones (which is a good thing, but not for your engine.


What on earth are BMW thinking then ?


Wasn't clear enough?..
 
Originally Posted By: bubbatime
Who cares? It doesn't matter. It's a $500 car.

Close thread.


crackmeup2.gif
 
Where does the engine with a 9 quart oil sump with upto 40000 km or every 2 years or whatever the oil life monitor says should comes first fit then ?

Without science behind there OCI is it BoolSheet or with science and proven field experience a long OCI maybe but not forever unless you replace oil at 1 quart per 1000km - 1500km km due high consumption and replace the oil filter every 10000km with dropping the oil out of the sump.

With "ASSYST", for the first time at Mercedes-Benz service
intervals up to 40,000 km or 2 years (min. 15,000 km or 1
year) are made possible. The system takes into account
individually the driving style of the customer by evaluating
engine speed, engine temperature, engine load and time.
The timing of the service required is calculated and the due
date is displayed to the customer in the instrument cluster.

This is from link below

https://bevo.mercedes-benz.com/d/d/en/Spec_215_0.pdf
 
Last edited:
Originally Posted By: AIRJAC3
Originally Posted By: bubbatime
Who cares? It doesn't matter. It's a $500 car.

Close thread.


crackmeup2.gif



Its sentimental value is priceless and gives immense pleasure so THERE.
 
Guy at work has an AMG63 - told me it is $500 for an oil change -
[censored], if nothing else would get folks off 3k OCI - "that ought a doer !" 🦃 ...
 
Originally Posted By: virginoil

Without science behind there OCI is it BoolSheet or with science and proven field experience a long OCI maybe but not forever unless you replace oil at 1 quart per 1000km - 1500km km due high consumption and replace the oil filter every 10000km with dropping the oil out of the sump.





Do you need much science to know new oil is always better than used (contaminated) one?.. Not so much science needed in this case, just the capacity to use your brain...
 
Last edited:
Originally Posted By: Thebimmerfan
Originally Posted By: virginoil

Without science behind there OCI is it BoolSheet


Do you need much science to know new oil is always better than used (contaminated) one?.. Not so much science needed in this case, just the capacity to use your brain...


Not sure what brain capacity there is to use here to interpret whats said ?

Did you read the post if you add enough oil due to high consumption oil change maybe a waste. Just change the filter.

I am not sure what your point is, due to the direction the response could take me.
 
Last edited:
Originally Posted By: Thebimmerfan

Do you need much science to know new oil is always better than used (contaminated) one?.. Not so much science needed in this case, just the capacity to use your brain...

The science seems to suggest that new oil isn't always good.

There seems to be particular weight in the idea that changing every 5,000km or more frequently results in more wear, but changing too infrequently also causes additional wear.

The sweet spot in the middle is where those actually using UOA's are aiming for - not too short an interval, but not too long. Once you have established that, there is little need to continue spending money on UOA's, unless you like to understand what is ending up in the oil.

Our old adage "Black = Bad," "3 Months/3K miles," "Oil is cheap insurance" only serve to line the pockets of oil companies, and may offer no real benefit to us over the lifetime of a car. After-all, we are talking about small ppm differences in wear.

Change four times annually per the old adage = four times as much money spent over the car's life that may well have done little-nothing in terms of allowing the vehicle to reach 200,000-300,000 miles. And at that point, the engine might be good, but everything else has gone to pots and the car is worthless and your money wasted.
 
Originally Posted By: B320i

The science seems to suggest that new oil isn't always good.

There seems to be particular weight in the idea that changing every 5,000km or more frequently results in more wear, but changing too infrequently also causes additional wear.

The sweet spot in the middle is where those actually using UOA's are aiming for - not too short an interval, but not too long. Once you have established that, there is little need to continue spending money on UOA's, unless you like to understand what is ending up in the oil.

Our old adage "Black = Bad," "3 Months/3K miles," "Oil is cheap insurance" only serve to line the pockets of oil companies, and may offer no real benefit to us over the lifetime of a car. After-all, we are talking about small ppm differences in wear.

Change four times annually per the old adage = four times as much money spent over the car's life that may well have done little-nothing in terms of allowing the vehicle to reach 200,000-300,000 miles. And at that point, the engine might be good, but everything else has gone to pots and the car is worthless and your money wasted.


Changing oil too often may result harmfull to your wallet, but there's no way new oil leading to more engine wear, this is just absurd. I have always done short OCIs, my driving style requires it, and all of the engines of my cars have been in perfect shape with no considerable wear, no compression loss, no eaten cam lobs and others lubrication-related problems even with more than 650 000kms. I know people who prefered to follow absurd manufacturer's recomendations for oil change intervals of 30 000 kms and their engines were dead with 160 000kms.
I agree with you that changing oils with less than 5 000kms on most cars is a waste of money, but such oil changes at least won't waste your engine, which would most probably be caused by ridiculously long OCIs of 20 000miles which can be found nowadays from many manufacturers. First 4 years (200 000kms) obligatory free maintenance schedule made many car-makers to reconsider their recomendations for OCIs and to double and triple them, given the fact that in recent years they are the ones that have to pay for them.
 
Last edited:
Originally Posted By: Thebimmerfan

Changing oil too often may result harmfull to your wallet, but there's no way new oil is leading to more engine wear, this is just absurd...


^ This
 
Originally Posted By: wemay
Originally Posted By: Thebimmerfan

Changing oil too often may result harmfull to your wallet, but there's no way new oil is leading to more engine wear, this is just absurd...


^ This

Uh, go and check the whole of BITOG, then the rest of the internet before making that claim.

This is happening exactly as the thread suggests: New oil takes time to build a layer of additives. It doesn't just 'start working' the minute you start the engine. Engine oil isn't effective till it reaches close to full operating temperature. Industry experts posting on here have stated this time and time again.

In that time before the protecting film exists, more wear occurs. As I said though, over the life of the car it may not enough to be detrimental.

Talking about 30,000km intervals, you will find plenty of those in the trucking community regularly run such intervals, and so can anyone else running good oil and using their vehicle primarily on long trips. Again, using oil analysis is the only way you can be sure that isn't harmful to the engine.
 
Status
Not open for further replies.
Back
Top