FYI, DIfferences in TBN Tests

[Jim Allen]

There are two TBN tests common to test labs, ASTM 2896 and ASTM 4739. ASTM 2896 will read about one unit higher than 4739. ASTM 4739 is often preferred for used oil, but labs can use either. The oil companies Data Sheet listings are almost always ASTM 2896. I learned this by talking to techs at WearCheck and ANA Labs. I can tell you:

WearCheck Uses ASTM 2896
ANA Labs Uses ASTM 4739

I have seen posted here that Blackstone uses ASTM 4739 but I have not confirmed that. If anyone can check and confirm Blackstone, and the other labs we use and post here, perhaps we can compile a list for a sticky so that we may be better able to compare TBN results.

 

[Cup of Joe]

Polaris uses D4739, they perform testing for OAI under contract.

Quote:
In the past, standard practices for determining optimal drain intervals using fluid analysis have required testing the oil for TBN and TAN. The theory was that when new, an oil’s TBN is high and its TAN is low and the longer the oil is used, TBN decreases while TAN increases. At the point at which they meet is the optimal time to change the oil. It is important to note that ASTM D-4739 should be used when testing the TBN of used (in-service) oils as opposed to ASTM D-2896, which may be used when testing TBN in new oils. ASTM D-4739 uses a weaker acid for titration than does ASTM D-2896 and therefore produces slightly lower TBN results.



http://www.polarislabs1.com/optimizing-drain-intervals-using-tbn-vs-tan.php

 

[dparm]

The 65% thing is interesting, I'd not heard that anywhere. Blackstone always pushed the "TBN < 1.0 = bad" thinking.

 

[Cup of Joe]

2896 yeilds a higher value then 4739. As an example Amsoil data sheets report in 2896. When someone performs a VOA it is tested with 4739 so the TBN on a VOA will be roughly 2 points lower then stated on the website.

Quote:
Total Base Number (ASTM D-2896) 12.6


http://www.amsoil.com/storefront/azo.aspx

 

[Jim Allen]

Originally Posted By: TaterandNoodles
When someone performs a VOA it is tested with 4739 so the TBN on a VOA will be roughly 2 points lower then stated on the website.




Both the labs stated one unit difference between the two methods.

 

[Cup of Joe]

Look through the VOA's where a starting TBN in published using 2896. As an example here is a VOA I did of Amsoil ASM tested by Polaris. Published TBN was 12 as tested 9.81 a difference of 2.2. I also did a VOA of ACD starting TBN again was 12 as tested 10.6 a difference of 1.4.

I would say a range of 1-2 points.

http://www.bobistheoilguy.com/forums/ubb...rue#Post1328517

http://www.bobistheoilguy.com/forums/ubb...rue#Post1326398

 

[Jim Allen]

I think you may have variables in some of your examples due to lab errors, etc. but I honestly don't know enough to argue. However, when two experts in the field, who do both tests every day, say definitively, "we allow one unit difference between the two methods," I have to give that a lot of credence. But I'll still be comparing on my own, as you did, until it's crystal.

 

[Gene K]

Originally Posted By: TaterandNoodles
Look through the VOA's where a starting TBN in published using 2896. As an example here is a VOA I did of Amsoil ASM tested by Polaris. Published TBN was 12 as tested 9.81 a difference of 2.2. I also did a VOA of ACD starting TBN again was 12 as tested 10.6 a difference of 1.4.



Does Shell publish using D2896 or D4739? The reason I ask is Polaris is getting approximately the same TBN using D4739 as spec on Shell Rotella.

Im wondering if their could be that much difference depending on oil construction.

 

[Quattro Pete]

Originally Posted By: Jim Allen

I have seen posted here that Blackstone uses ASTM 4739 but I have not confirmed that. If anyone can check and confirm Blackstone,

Yes, Blackstone has been using ASTM 4739 for the past few years or so. Before that, it was 2896. So, if you're looking at old UOAs/VOAs here, they were most likely done using the old TBN test method (2896).