Too Much "TBN"?

[SWS]

I have seen various comments about making sure that the TBN level is >2 and how the oil is OK "until the TBN is used up". It is possible that in their zeal to control acids for long OCI that some suppliers formulate their oils too basic? If so, then would it be true that new oil would not be as "good" as that same oil that is slightly contaminated with acid, making a more neutral mix? I am thinking that rubber seals, etc would deteriorate in the presence of a strong acid or a strong base....

Some questions:
1) What are the max ranges of TBN observed on new oil?

2) What is the TBN of M1 5W-30?

3) Assuming constant acid comtamination of the oil due to the same stop-and-go driving and same driving routes on the same car, is TBN "used up" linearly or does it suddenly drop off?

4) Are all additives the same in this regard? In other words, does one oil's additive package stand-up to acids as well as another's? Which oils are better at maintaining TBN?

Thanks for your advice!

SWS

 

[TC]

"1) What are the max ranges of TBN observed on new oil?"

Most firms don't list TBNs in their spec sheets, but they may be available through virgin oil analyses. From the 15 or so spec sheets I have, a low might be Union 76 and Kendall GT-1 at 6.2, and a high might be Rotella and Pennzoil Long Life at 11.5. Synthetics fall somewhere in between, closer to the high end occupied by diesel lubes.

 

[Robbie Alexander]

Some questions:
1) What are the max ranges of TBN observed on new oil?
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Depends on MFG
5/6 - 10/12 even 15+ or MORE
TBN alone is not the Garden of Eden
Some here look at the TAN more than the TBN
I am on the TBN bandwaggggggon. Unless someone will explain how to look at an oil with the TAN???

What you want to look for is a slow and stable tbn drop IMHO, and IMExperience when it goes it will be at the very end and it will go quickly, however it will usually last longer than the oil because if you do oil samples, the oil will be USED up before TBN dies... that said... IF YOU NOTICE TBN drop suddenly at an early stage, there is a reason (mechanical of some kind).


3) Assuming constant acid comtamination of the oil due to the same stop-and-go driving and same driving routes on the same car, is TBN "used up" linearly or does it suddenly drop off?
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yes and no. more jagged or see-saw-ed IMO
But generally will slope based on miles...
If you run the same oil every OCI, I would say you could kinda guess where it will be and what milage. Not always because a dirty engine or poor EGR or other factors like non tune-up or oil leak could cause it to drop faster because of the oil fighting to clean....


4) Are all additives the same in this regard? In other words, does one oil's additive package stand-up to acids as well as another's? Which oils are better at maintaining TBN?
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Additives like foods. You have fast foods, you have hormone induced or modified/altered foods or organic or REAL VEGAN organic.... different quality adds... in answer, each blend has its unique make-up.

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[haley10]

I think Exxon/Mobil that implies long drains and Amsoil that sells this concept do a lot of seal compatibility testing. Others do also. I don't see a problem with most oils, so I don't think too high TBN is an issue.

Raw TBN numbers are something I don't rely on. Higher is better, but it depends on how it got there. It depends on the quality of additives of how fast it drops, planes out, and how long it lasts in general. I look for ACEA B3, B5 specs. also in gauging if an oil may be used for longer drains.

It's usually the other factors that get you first, before TBN does. Going out of grade, fuel dilution, and especially insolubles get you way before TBN is a problem.

Generally the TBN of M1 show somewhere around 4.7 after being run about 5,000 miles on Blackstones' test. TBN is not taxed at all, but your solids will start going up with a standard filter. This is a limiting factor in my mind.

 

[Baveux]

quote:

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Originally posted by haley10:

It's usually the other factors that get you first, before TBN does. Going out of grade, fuel dilution, and especially insolubles get you way before TBN is a problem.

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That being said, if your oil analysis show normal wear, no excessive contamination in oil, visc in grade, you can assume that the oil is still good and that the tbn and additive package isn't completely depleted ? Am I right ?

 

[Robbie Alexander]

It's always always always about the wear numbers for YOUR motor. TREND it out and build the database in your mind of the average... perhaps even plot it out on graf paper...
WHEN you see numbers start to rise faster than normal but are still in the safe zone... that is where it is starting to be pushed.

Example if a number is:
0.01 0.04 0.03 0.05 0.04 0.06 ---2.0 7.0
or
2 3 2 3 4 5 3 4 4 4 5 5 ---8 18

Now the pro's here should be able to give better examples.... it's always in the trend and when it starts to spike then drain.

quote:

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Originally posted by Baveux:

Originally posted by haley10:
[qb]
It's usually -*-*-

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That being said, if your oil analysis show normal wear,