Note to forum members:

These posts were originally in a recent thread titled 'Quaker State?'. The topic turned to discussion of Total Base Number. Since there was significant information being discussed it seemed deserving of it's own topic for discussion.

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greenpus
14-Jun-02, 08:36 AM (EST)
Does that mean if you decide to do extended oil changes in a car that you would be better off with oil rated for diesel engines so your oil does not get overly acidic?

horsepuller
14-Jun-02, 09:48 AM (EST)
Oils intended for diesels have a higher Total Base Number. Acid can still form from the moisture in the combustion gas of gasoline vehicles, but not as great as with fuel that contains sulfur. In the days before unleaded gasoline, regular leaded gasoline blends contained 'light straight run' (LSR) which was a distillate that contained sulfur. LSR was also known as 'white gas'.

greenpus
17-Jun-02, 12:43 PM (EST)
I think BrianA is using the same company (http://www.oillab.com/) I did when I ran tests on my oil. I had to pay extra for the TBN test. At 15,000 miles my Mobil 1 Tri-Syn sample had a TBN of 2.XX. I haven't called them yet to find out what this means yet. It seems pretty low whatever it means.

greenpus
17-Jun-02, 12:56 PM (EST)
I just got off the phone with the oil lab and they told me my oil was unacceptable because of the TBN level. Mobil 1 Tri-Syn starts out at 12 and the longer you use it the TBN numbers go down which means the acid goes up. For Mobil 1 a TBN of 5 or so is acceptable but at 15,000 miles mine was 2.XX. This will cause pitting in the softer metals of the engine. Live and learn........

TorqueKing
17-Jun-02, 01:54 PM (EST)
Greenpus, so how many miles is Mobil-1 good for? You said you ran 15k, but how many miles could you run and be over 5 TBN?

greenpus
17-Jun-02, 03:58 PM (EST)
I don't know. Every 5000 miles I took a sample and sent it in for testing. At that time I did not know about TBN so I did not have it tested until 15,000. Since I did not know about the acid level I pretty much screwed up my tests.

horsepuller
17-Jun-02, 08:06 PM (EST)
greenpus, was your test vehicle diesel or gas?

greenpus
18-Jun-02, 09:20 AM (EST)
Gas

BrianA
18-Jun-02, 09:37 AM (EST)
Greenpus,
Interesting info on the TBN for Mobile 1. The topic has strayed from Quaker State to your M1 TBN numbers. I hate your info is buried in this thread.....
I'm left to wonder...is the low TBN after 15,000 miles a reflection of your engine or the M1? You might not have the answer, but what is your gut feeling? Your information ties in handily with the conventional-vs-synthetic debate, and I'd like to have more information or opinion.
As always, Thanks,
Brian A
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Hopefully now we can use the information already discussed and add to it with our research and oil analysis.

 

Thanks Scott, good idea.

Since some have asked..here is some info from various sources. Maybe overkill, but here it is anyways....

Total Base Number (TBN) the quantity of acid, expressed in terms of the equivalent number of milligrams of potassium hydroxide that is required to neutralize all basic constituents present in 1 gram of sample. (ASTM Designation D 974.)
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Total Base Number (TBN): A classification of an oil's reserve alkalinity. Its ability to reduce the acids that form as a result of fuel sulfur content, high heat, condensation, and combustion processes. Acids formed in an engine's crankcase can etch and ruin bearings.
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NEUT NUMBER OR NEUTRALIZTION NUMBER:
The specific quanity of reagent required to "neutralize" the acidity or alkalinity of a lube sample. Either of these characteristics - acidity or alkalinity - may be exhibited by an unused oil, depending on its composition. In addition, certain additives impart acidity, while alkalinity may be derived from the presence of detergents or of basic material added to control oxidation. In service, the oil will show increasing acidity as the result of oxidation, and additive depletion. Though acidity is not, by itself, necessarily harmful, an increase in acidity may be indicative of oil deterioration, and the neut number is widely used to evaluate the condition of the oil in service. The most common measurement is ACID NUMBER, the specific quanity of KOH (potassium hydroxide) required to counterbalance the acid characteristics. How high an acid number can be tolerated depends on the oil and the service conditions. Only broad experimentation with the individual situation can determine the value. Neut number is determined in accordance with the ASTM method D664 or D974. The former is a potentiometric method, the latter, colormetric. Values for Total Acid, Strong Acid, Total Base, and Strong Base can be obtained. Strong acid numbers are considered to be related to inorganic acids, such as those derived from sulfur, while the difference between the total and strong acid numbers is attributed to weak (organic) acids. A total acid number (TAN) and a total base number (TBN) can exist simultaneously, both representing components too weak to completely neutralize the other. When results are reported simply as "neut number" or "acid number", a Total Acid Number (TAN) is implied.

Later,
Brian A