1.0 is the right TBN cut-off for [wear]

[vinu_neuro]

I've gotten confused over the years about where TBN condemnation points should really be. Some labs go for 35% of initial value, some go for TBN/TAN intersection. According to a Honda paper, 1.0 is the point past which wear starts increasing. However, Blackstone is way off the mark in telling people that this is sufficient.

As important as TBN is oxidation over a long interval. Higher oxidation is first going to show up as deposits. First at the pistons, which isn't going to show up in a UOA. When comparing M1 and PP/PU, I saw some UOA's where TBN still measured 1.0-2.0 but Pennzoil showed signs of oxidation in the form of significant viscosity thickening, yet Blackstone was happy to tell the user to push on.

Thankfully most who do extended oci's do use some kind of M1 that seems to have better oxidative stability than just about anything else.

 

[friendly_jacek]

Great points. Agree 100%. The only thing is the oil formulations are moving target.

 

[Quattro Pete]

Originally Posted By: vinu_neuro
According to a Honda paper, 1.0 is the point past which wear starts increasing.

1 according to which test procedure? There are several.

 

[tig1]

I don't do UOAs(rare exception)and in the 37 yeras of doing 10K OCIs I never worry about TBN.

 

[dparm]

1.0 is just a very generic rule-of-thumb some use. TBN by itself is only part of the picture. You have to look at the report as a whole, and pay for TAN.

 

[vinu_neuro]

Originally Posted By: Quattro Pete
Originally Posted By: vinu_neuro
According to a Honda paper, 1.0 is the point past which wear starts increasing.

1 according to which test procedure? There are several.


Great question, I don't know and makes this a little irrelevant without knowing that. I emailed the authors, hopefully will hear back.
There's 2896 and 4739. What other TBN test methods are there.

Originally Posted By: tig1
I don't do UOAs(rare exception)and in the 37 yeras of doing 10K OCIs I never worry about TBN.


Good for you.

Originally Posted By: dparm
1.0 is just a very generic rule-of-thumb some use. TBN by itself is only part of the picture. You have to look at the report as a whole, and pay for TAN.


TBN is only part of picture, you have to look at the report as a whole and pay for Oxidation.

I believed TAN was necessary as well. Top labs like Wearcheck and Polaris both maintain that only TBN is necessary for gasoline engines and TAN matters more for CNG, drivetrain components, hydraulics, etc.

And Honda hasn't spent years working on TAN estimation models, for their olm system. Only Base Number modeling.

I think NO2's old post has merit.

Originally Posted By: NO2
So, as I understand it, TBN is simply a measure of buffer quantity. Since acids are generated at a fairly linear rate, the TBN measured buffers are consumed mostly at first and over time, less so as quantity decreases and secondary buffers (e.g those measured by Ca content + others) are consumed at a higher rate. TAN is irrelevant at TBN > 1.0 (given that the acid has been neutralized) and only becomes significant as secondary buffers become less effective and acid may increase.

So why is TAN necessary with a non-depleted TBN reading?

 

[A_Harman]

Maybe because major oil blenders such as Mobil and Castrol are using more Mg-based detergents, which have been documented to be not totally effective at neutralizing weak acids. So TAN could be increasing, even if TBN is still showing active additive available.

 

[vinu_neuro]

Originally Posted By: A_Harman
Maybe because major oil blenders such as Mobil and Castrol are using more Mg-based detergents, which have been documented to be not totally effective at neutralizing weak acids. So TAN could be increasing, even if TBN is still showing active additive available.


That was the case with Mg-based additive technology maybe 10-15 years ago. Things have moved along.

 

[CT8]

Wouldn't it be for corrosion?

 

[vinu_neuro]

Honda replied regarding TBN test method. The method used in the paper is JIS2501 5.2.2. Per the author, the JIS2501 5.2.2 method is mostly same as ASTM D4379.

 

[JAG]

Great thread. Thanks for the information.

 

[benjy]

just read info by Machinery Lubrication, they said a BN of 3 is time to change!! also some interesting info on thin x-20 oils ford in europe will not warranty x-20 oils in fact none are available, they still use 5-30 for better protection in the long run.

 

[supercity]

Originally Posted By: benjy
just read info by Machinery Lubrication, they said a BN of 3 is time to change!! also some interesting info on thin x-20 oils ford in europe will not warranty x-20 oils in fact none are available, they still use 5-30 for better protection in the long run.


Not just a 5w30 but an A5/B5 rated 5w30 that meets WSS M2C 913 is required.

 

[Boss302fan]

Originally Posted By: supercity
Originally Posted By: benjy
just read info by Machinery Lubrication, they said a BN of 3 is time to change!! also some interesting info on thin x-20 oils ford in europe will not warranty x-20 oils in fact none are available, they still use 5-30 for better protection in the long run.


Not just a 5w30 but an A5/B5 rated 5w30 that meets WSS M2C 913 is required.



Which 5W30's meet these specs?