[JFP in PA]

Originally Posted by 941MXVET

JFP,

I spoke with the lab, they do not do TBN's for gas engine samples.

Ask them why not, it is an important value..............

From a well known lab's website:

"Do I Need a TBN?

What is a TBN, and who uses it? In short, a TBN (total base number) measures the amount of active additive left in a sample of oil. The TBN is useful for people who want to extend their oil usage far beyond the normal range.

By comparing the TBN of a used oil to the TBN of the same oil in virgin condition, the user can determine how much reserve additive the oil has left to neutralize acids. The lower the TBN reading, the less active additive the oil has left.
(Note: You do not need to send in a virgin sample for us to run a TBN on your oil. Some people like to send a virgin sample anyway, to find out exactly where the TBN of a specific oil starts out. The cost of a virgin oil sample plus TBN is the same as a regular oil sample plus TBN.)

An oil's function is to lubricate, clean, and cool the engine. Additives are added to the oil to enhance those functions. If the oil becomes too acidic, it will corrode the engine. A good TBN result, meaning plenty of active additive is left in the oil, is usually in the 6.0 to 14.0 range (depending on whether the oil is for gas or diesel engines). A low test result, meaning very little additive is left, is down around 1.

Scientifically speaking, the TBN is one of two "neutralization number" tests run on oils. The TAN (total acid number), which is used for hydraulic oils, is the other. The TBN measures the total basedity of an engine oil; that is, how much base (as in, a base vs. an acid) additive is in the oil to offset the deleterious effects of acids coming into the oil from combustion and other sources. "