What should the minimum TBN be for a UOA?

[cp3]

Originally Posted By: edhackett
It doesn't really correspond to any of the ASTM methods, but since it uses hydrochloric acid as a reagent(not the titrant), it would be closest to ASTM D 4739.

They list the MDL at 0.6 TBN, accuracy of +/- 10%+MDL, and MQL at 1.8 TBN.

This means that if you receive a TBN reading of 4.0, that's 4.0 +/-1.0 and the method cannot accurately measure TBN below 1.8.

Ed




Based on that, what would be a safe condemnation level? Or should I find a different lab...lol

 

[edhackett]

Originally Posted By: Quattro Pete
Wouldn't it show up as elevated insolubles?


I've seen UOAs here from sludged engines that did not show abnormally high insolubles. Looking at it from a purely common sense angle, we see varnish and sludge attached to the metal or laying in the head/pan. If it's not in suspension in the oil, it isn't there to be picked up by UOA.

Ed

 

[edhackett]

Originally Posted By: cp3
Based on that, what would be a safe condemnation level? Or should I find a different lab...lol


I found this on their site. Page 16 gives some good information on how it corresponds to the other methods. It's not that bad, but accuracy will never be as good as the proper titration to the inflection point as used in the other methods.

http://www.dexsil.com/pdf/2008_brochure.pdf

Ed