TBN % Change

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Based purely on the TBN and TBN only: What % change from New oil TBN levels to current TBN levels listed in the UOA's, do you consider a point in and of itself as a flag to change the oil?
 
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I'd really be interested if one of the lab people could tell us how much titration (adding of acid) it takes to get the TBN to start decaying. That is, I wonder to what extent oil is "buffered". I wonder if they just use a Ph meter and see when it hits neutral [Confused] . Typically ..unless you have an "ion balanced" liquid ..the neutralization is not linear. That is, you'll add xxx amount of acid before it even moves toward neutral ..THEN is decays more rapidly. There does seem to be a consensus that 70-75% ..or 25% remaining is an accepted level. My only UOA had a TBN of 2.5 ..and was deemed shot (10 was the assumed starting point).
 

Robbie Alexander

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Originally posted by Gary Allan: *-*-..the neutralization is not linear. That is, you'll add xxx amount of acid before it even moves toward neutral ..THEN is decays more rapidly. *-*-*- (10 was the assumed starting point).
True, not linear... but not always too far off... I have seen this done on a graf, over time it seems like it starts to form a VERY nice predicted pattern (roughly speaking) and anytime it goes out side the graf borders (as like in Stock Technical trending) there is always a problem. It works like the Blotter test of sorts, however I have never decided to do that in my regime. As far as TEN being the assumed TBN starting point, ARE you sure? The Mfg can be using one ASTM method to determine the TBN, and almost without exception I think the Labs use the other. The MFG can or IMO probably should use the TBN that looks at the TOTAL components, while the labs look at the Components as they HAPPEN with WEAR, subtracting components parts of the ADDS... I think I said that right.
 
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quote:
As far as TEN being the assumed TBN starting point, ARE you sure?
No, but this is what Blackstone said was probably my starting point (it decayed to 2.5 and was deemed all but shot). I didn't have a VOA to compare it to (Mobil 1). I'm just going by my experience with acids (in place of "acid formation") and alkilyns where if the fluid is buffered (like with sodium bicarbonate for example) you can add a butt load of acid and the stuff will never move toward neutral. Once you deplete the buffering agent ..the stuff tracks in a quasi-linear manner. That is, something with a Ph of 9 that is buffered with sodium bicarbonate will take 10 times the HCL to make it become less than 9. This is opposed to a liquid that is just adjusted to 9 Ph with SodiumHydroxide (caustic). That is, if I was using the method that Blackstone uses to determine in my above scenereo ...and assuming a starting point of "9" ..I could remain at a TBN of 9 for xxx amount of miles ..then have it drop off rather quickly. That's why I wonder if the TBN number decays in an "inversely proportional" manner (assuming the same operational insult) ..or expotentially (half the distance "again" 4x the decay) ..or if it has no linear component at all for xxxx amount of insult ..then decays along one of the aforementioned rates. Blackstone's site describes it as: 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. So I wonder if they just drop a Ph probe into the oil ...have it mixing (one of those magnetic thingies spinning via the magnetic force generated from the plate under the sample) and titrate acid into the solution until it reaches 7.0 Ph. I would think in a VOA that they would not see the needle head toward neutral immediately like it would in a "simple" base solution. Just more monumental things to ponder on our quest for the Holy Grail ... [Big Grin] Now we can seek a new standard ....TBN "reserve" factor [Big Grin] [ December 30, 2003, 10:06 AM: Message edited by: Gary Allan ]
 

Robbie Alexander

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quote:
Originally posted by Gary Allan: [QUOTE] -*-*-* Now we can seek a new standard ....TBN "reserve" factor [Big Grin]
thats what the UOA's show, the reserve factor ( a good guess, because from my info, the TBN is still kinda tricky, and not exactly precise... Always have some reserve.
 
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quote:
thats what the UOA's show, the reserve factor
Yes, but that's not what I was comically referring to. I was referring to "buffering" ..that is the amount of insult a 12 TBN could withstand and still be a 12 TBN. Perhaps VIRGIN TBN Reserve would have been a better description of what I meant [Big Grin]
 

Robbie Alexander

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quote:
Originally posted by Gary Allan:
quote:
thats what the UOA's show, the reserve factor
Yes, but that's not what I was comically referring to. I was referring to "buffering" ..that is the amount of insult a 12 TBN could withstand and still be a 12 TBN. Perhaps VIRGIN TBN Reserve would have been a better description of what I meant [Big Grin]

I think I understand... Yes, virgin reserve is better... BUT: my point is that it doesn't matter per se The Virgin TBN and the TBN just after a few miles or perhaps no miles is not the same due to my understanding; the acids already in the dirty engine are wiped out by the NEW oil...Thus if the TBN was 8, now it 6 or 5 or 5.4 (AS the starting TBN IN THE DIRTY ENGINE). From there it's, I believe, normal WEAR and TEAR that breaks down the oil. On top of this: TBN's are tricky to pinpoint, and are not THAT perfect/close to the "REAL" number in many cases... so there could be a couple point "SPREAD" . My main point was the TBN going in as 12, will not be 12 very long... At least in my cheap dino motor oil that I use it has not been the case. I'm talking from what I have seen, not any real knowledge. This is Life in the trenches experiences. My conclusions may be wrong and subjective, but there they are, it's by belief based on my limited knowledge how things work.
 
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