Can you have good wear, and good visc at 100C if the TBN number are low or very low ?
How long can you use an oil with the TBN at zero before you start to damage something ?
What are you going to damage first ? And how would you know that ?
Thanks
Tbn Wear Contamination ....
- Thread starter Baveux
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I doubt you'll find an answer to that question. As the TBN goes down it is an indicator that the additive package which primarily serves to hold down oil oxidation is shot. When you are at this point other properties of the lubricting fluid start to break down: viscosity being one of the most important.
The other issue is the TBN may have been accelerated by a faulty engine which may already have high wear rates, fuel dilution, blowby or antifreeze. In this case wear and corrosion will go up faster. So if this is the best answer you get on this post. Just trust experience and conventional wisdom, and realize that when the TBN gets around 2 its time to change. I believe TooSlick recommends 3. ![[Smile]](images/icons/smile.gif)
I like to see TBE abouve 4 in diesels and maybe 3 or so in gasoline engines, but that is just part of the equation. If it is dropping to those levels in less than 15,000 miles, something is wrong. Find the problem rather than figure out how low you can go
quote:Not sure I agree with that. Some engines just beat up the oil and reduce the TBN to 2 in 7500 miles or so. My V6 Camry does this and to say there is a problem I feel would not be accurate. Perhaps if there was a problem it owuld have died long before its current 161,000 miles.
Originally posted by widman: I like to see TBE abouve 4 in diesels and maybe 3 or so in gasoline engines, but that is just part of the equation. If it is dropping to those levels in less than 15,000 miles, something is wrong. Find the problem rather than figure out how low you can go
![[Wink]](images/icons/wink.gif){kind=icon}
Well, okay maybe just an old guy.
I use a cutoff limit of 4.0 on TBN, using the ASTM D4739 test protocol. That's about 2 pts higher than most oil analysis labs will use.
Ted- Joined
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Correct me if I'm wrong here folks.
The test for TBN is done by titraiting acid into the oil until you reach a neutral Ph. That is, the number measures the amount of acid required to do this (if I interpreted what Blackstone says it does to determine this number correctly). Hence it measure the amount of buffering in the oil ..or rather the oil's "reserve capacity" for acid formation resistance.
If that is correct ..anything over zero should be prefectly functional, albeit having NO CAPACITY for further insult.
I would think that TBN would decay, assuming a constant rate of insult, at a rate "inversely proprotional to the square of the duration". That is, if the TBN dropped 50% in 6000 miles ..if would drop another 50% in 1500 miles. ( I may have expressed this incorrectly ..bear with me and try and extract what I'm trying to communicate)
[QUOTE]Originally posted by Baveux:
[QB] Can you have good wear, and good visc at 100C if the TBN number are low or very low ?
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Sure... you can also run the tires all the way to slicks too, but in all likelyhood, you will have one place on the tire go bald first.
How long can you use an oil with the TBN at zero before you start to damage something ?
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At ZERO, I would guess not at all. I think there is a 1 or 2 point rate of error in TBN (maybe 10-20%), and on top of this, to me and maybe me alone, this is like asking how long can you run oil when you cant see it on the dipstick, or how many pounds under inflated can you go on all your tires before they blow because afterall you will intend to put air in them JUST before they get too hot and blow..
Hey, either get use to WASTING some oil or don't worry about it and do what everyone else does and don't care
Just how far under the safety zone can you pull the rip cord and still live and walk away unharmed> Answer, YOU are NOT suppose to DO that!
What are you going to damage first ? And how would you know that ?
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God Almighty only knows. What does it matter?
I would guess it would be damaging everything, to what extent I donno!
Baveux:
If you don't wanna change your oil don;t
If you think it's still good, it's not.
IF The TBN bothers you of getting say 5-6-7K out of the oil and you want longer... you need Oil Extreme or something like it
Robbie,Let me explain to you why I ask that question.
I do not want to do extended interval. I just want to follow the oil life monitor on both of my cars.
My latest UOA showed me that the TBN was low (1.07) however all other number, contaminents,wear were normal.
I want to keep taking oil analysis, but I'm a cheap kind a guy and I dont want to pay extra money for TBN reading.
The lab where I'm sending the sample told me that it is not absolutly neccessary to have that number, and I was trying to get opinion from the member here on how TBN is important if totally depleted for a short period of time.
It was so simple before this board and before the Oil life monitor...5000km and voila due for an oil change....!!!
quote:I think I recall your post! Yeah, I understand exactly, I too am a Cheap Son too... This is what I would do. Pick the oil you want to use, your gonna have to do some testing... find out all the back ground info on it, and if your smart, you will start with one with a higher TBN, then just pick a number safe to you say like 75% of that number. Then run several OCI's The first pull and drain at say 3K The second run you will pull a sample too but longer than 3K, Then the third... You will find a place that your car averages... IF 75% drop in TBN is okay with you (me maybe 50% - you determine your own numbers) then this is the milage. I would also be pulling the POOR MAN"S oil test along the whole way... maybe every week or every 1-2K or whatever you feel like. Then after watching close you can sorta tell just by it when time is ready to do the drain by the way the oil is loaded-up... Again as far as my first post on the matter, if you are worried, you need something like Lube Control / Oil Extreme or whatever... I'm not endorsing any of these things, but they most likely will aid you in going longer drains.
Originally posted by Baveux: Robbie,Let me explain to you why I ask that question. I do not want to do extended interval. I just want to follow the oil life monitor on both of my cars. My latest UOA showed me that the TBN was low (1.07) however all other number, contaminents,wear were normal.-*-*-*
You know what Robbie, F... the oil life, f...the oil sample, the cheap man is going back to a 6000km schedule , why bother, I'm sure the oil can do it, and I have more important thing to do than worry about how far I can stretch 8 bucks !!!
I spent lots of time here and I've learned a lot and I thanks you all for that, but I think those headaches aren't for me. Maybe that disease will get at me again sometimes in 2004 but for now all I have to say it's bye !!!
Merry Christmas to all ,
My answer was based on my experiences with 1000 or more samples. The only oils I've found problems with (below 4) are Bolivian made Pennzoil, YPFB (made by Petrobras), Brazillian made Lubrax, and another Brazilian made product. Mostly I analize the two brands I represent, and I have only seen TBN in the 4 or 5 range when there are serious problems with injectors, raw petroleum mixed with the diesel fuel, extreme blowby (compression 70 psi), maybe one or two other causes that don't come to mind at the moment. If I had a car where the TBN was dropping so much and therest of the conditions seemed right, first thing I'd do is try a different oil.
quote:Well the first thing I'd do is SHORTEN THE OCI and look for the problem. My cut-off is much higher, but my starting TBN is too. If I were to guess, I'd say it is possible that a BETTER and STRONGER oil (changed to) may be working overtime to clean up old gunk, and then would drop the TBN faster.
Originally posted by widman: -*-*If I had a car where the TBN was dropping so much and therest of the conditions seemed right, first thing I'd do is try a different oil.
quote:with you 1000% That's the problem with making a pree-meee decision. IMO the runs most guys go through won't consider a real run.
Originally posted by widman: That's exactly one of those conditions.... I feel you really need an oil in an engine 3 change cycles before you really know how it is working.
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