TBN

[buster]

From Solarent:
Quote:
"The tricky part about TBN is that there are more then one way to test for it,and as you indicated,some detergent compounds do not show up on the testing. Also,how the detergent reacts with other additives in the system also plays into TBN retention. There have been several arguments one way or the other about how accurately a TBN measurement follows the ability of an oil to deal with acidic biproducts. In some cases,the detergent does not act on acids at all,leaving its base in tact when really the acidity is reaching dangerous levels.

AS Mobil does not disclose the TBN on it's pds - at least not on the one I found; it is difficult to say for certain that the low TBN reported by VOA is an accurate representation of it's ability to deal with acids. TBN retention is also equally affected by operating conditions,fuel dilution and other factors as much as it is additive formulation. This is why in some cases a high TBN oil will deplete faster than a lower TBN oil.

Detergents that produce low levels of sulphated ash are becoming much more popular (especially with oils used in diesel equipment); which in some cases are not showing up on testing the same way that Calcium"

 

[buster]

I've been curious about the lower TBN in newer formulations and an oils ability to fight acids over long drains. He raises an interesting point.

 

[tig1]

I mentioned this in the most recent discussion about TBN retention. I'm very confident that Mobil 1 oils are well protected for the warranty period of regular Mobil 1(10K) and also EP(15K). Thanks for this post.

 

[buster]

I don't know how true it is though.

 

[tig1]

Originally Posted By: buster
I don't know how true it is though.


I am on my 3rd 10K OCI with 0-20 and all is well. I won't spend the money on used oil analysis to determine TBN as I see no need to. Also I believe XM would not jeopradize their reputation by producing oils not up to the warranty requirements.

 

[buster]

True.

Your Ford engines could go 10k on Motorcraft though, so I don't think that means much.

 

[Capa]

Some of us have wondered just how accurate TBN is in regards to very accurately predicting the life of an oil. Is it possibly slghtly overrated?

 

[buster]

Possibly, yes.

 

[tig1]

Originally Posted By: Capa
Some of us have wondered just how accurate TBN is in regards to very accurately predicting the life of an oil. Is it possibly slghtly overrated?


I'm with you. I raised this question some time ago. I am thinking TBN is way over rated for extended OCIs.

https://bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2522167#Post2522167

 

[tig1]

Originally Posted By: buster
True.

Your Ford engines could go 10k on Motorcraft though, so I don't think that means much.


As I have never used MC oils, and you may be right. These Ford Duratechs are excellant engines.

 

[Artem]

Originally Posted By: tig1


I am on my 3rd 10K OCI with 0-20 and all is well. I won't spend the money on used oil analysis to determine TBN as I see no need to.


Kinda going at it blindly, IMO. I guess with your experience, you should be confident that all is "fine".

 

[Solarent]

I hope my comment doesn't give the impression that TBN is not valuable in evaluating the lifespan of the oil. I would suggest that for extended drains, one should not rely on TBN alone, but should consider all aspects of their analysis results.

Here is a paper from the SAE on the subject written by the guys at Oronite (which is a chevron company I believe). It is a little dated, but has been referenced as recently as in the ASTM Comprehensive Review of Lubricant Chemistry text from 2009 and The Chemistry and Technology of Lubricants by Springer in 2010. In Diesel oil technology there was a big concern about the lower levels of TBN due to the need to reduce sulphated ash to meet the CJ-4 specification. The answer was these ashless detergents which in many cases do not show up the same way on used oil analysis testing.

I would not be greatly concerned about the ability of Mobil 1 Extended Performance over the extended drains based on a low TBN that shows up on a third party analysis where I didn't know which test method was used. However any drain interval greater than 10 000 miles I would always recommend following a used oil analysis trend with a TAN/TBN check done every other analysis.

 

[buster]

Not at all, thanks for sharing Solarent.

 

[LckydevL]

With TBN retention rates in oils being different.

How do we know that one oil might go 3k miles between 2.0 and 1.0?

Some of the oils nowadays start out lower than they ever have but still last as long or longer than previous formulas.

 

[BMWTurboDzl]

Originally Posted By: LckydevL

With TBN retention rates in oils being different.

How do we know that one oil might go 3k miles between 2.0 and 1.0?

Some of the oils nowadays start out lower than they ever have but still last as long or longer than previous formulas.



I would say "How do you know it's really 1.0?"

 

[Capa]

This is a controversial topic but I hope some of the big boys comment on whether TBN is the end all be all of oil life. I'm going to guess that it is a good indicator but not an absolute one.

 

[Doc Holiday]

Originally Posted By: Capa
This is a controversial topic but I hope some of the big boys comment on whether TBN is the end all be all of oil life. I'm going to guess that it is a good indicator but not an absolute one.

It doesn't mean much. At least not the beginning TBN. TBN retention is much more important. Example is Rotella 15w40 vs a house oil I sell. The house oil has a TBN that is much higher than the Rotella in the beginning. But check them again after 9500k and the Rotella will be far better than my house oil.

 

[Doug Hillary]

Hi,
with today's lubricants and fuels TBN alone is just one tool in the mix of UOA factors

Personally I (use) used both TAN and TBN (trended) as part of my determination of lubricant life in extended OCIs in heavy high speed diesel engines

Others of course may think differently but its what has worked for me for a very long time indeed

 

[Solarent]

Originally Posted By: Doug Hillary
Hi,
TBN alone is just one tool in the mix of UOA factors

Personally I (use) used both TAN and TBN (trended) as part of my determination of lubricant life in extended OCIs in heavy high speed diesel engines

Agreed 100% here. TBN and TAN (trended) is one tool of many in the UOA tool box. I wouldn't call it the be all end all, but it is most definitely a good indicator, especially when considered in the context of the other results of your UOA.

To answer LckydevL's question the answer is the only way to really use TBN and TAN properly is to see it in your own equipment based on your own operating conditions. One of the biggest mistakes early UOA managers make (I know I did) was to put too much stock in what other people were seeing and not enough in seeing my own trends. Sometimes your operating conditions are what may cause a different result in the TBN retention of an oil, and so your own trends are critical in determining your ODI.

 

[Capa]

I
Originally Posted By: Doug Hillary
Hi,
with today's lubricants and fuels TBN alone is just one tool in the mix of UOA factors

Personally I (use) used both TAN and TBN (trended) as part of my determination of lubricant life in extended OCIs in heavy high speed diesel engines

Others of course may think differently but its what has worked for me for a very long time indeed


Doug, thanks for the reply. I, personally, find it odd that so many used oil analysis don't even report a TBN. Also, so many people seem to just look at the TBN and ignore the TAN.