Black Stone Oil Report...to Good To Be True?

[regular guy]

Originally Posted by Sebringjetta

well my main focus is keeping a eye on the rod bearings so iron/copper would be the big focus correct?

What year is your car?

[dparm]

Originally Posted by SenorFunkyPants

Whats the effect on the engine of having a high TAN?
Or more specifically the effect of sulphuric acid on engine bearings?

The acids attack pretty much everything. Namely, it causes corrosion that cannot be "burnt off" later on. The areas most prone to it are the valve train and cams.

For reference, when I changed my TWS after 7754 miles, the TBN came back at 3.4 and TAN at 3.4. When TAN = TBN that means you've effectively got a "neutral" oil. The conclusion I can draw is that for my specific engine and driving style, TWS is good for about an 8k change interval.

A person who has more highway driving and/or a warmer climate might be able to go longer. The only way to tell is to get it analyzed and look at the TAN/TBN relationship. If the TAN > TBN, you probably should've changed it a bit sooner. If TAN < TBN, you can probably leave it in there longer. Getting TBN alone is not that useful.

[Sebringjetta]

Originally Posted by regular guy

What year is your car?

2008 sir

[SenorFunkyPants]

Originally Posted by dparm

The acids attack pretty much everything. Namely, it causes corrosion that cannot be "burnt off" later on. The areas most prone to it are the valve train and cams.

For reference, when I changed my TWS after 7754 miles, the TBN came back at 3.4 and TAN at 3.4. When TAN = TBN that means you've effectively got a "neutral" oil. The conclusion I can draw is that for my specific engine and driving style, TWS is good for about an 8k change interval.

A person who has more highway driving and/or a warmer climate might be able to go longer. The only way to tell is to get it analyzed and look at the TAN/TBN relationship. If the TAN > TBN, you probably should've changed it a bit sooner. If TAN < TBN, you can probably leave it in there longer. Getting TBN alone is not that useful.

Brilliant...thanks for that. I guess that is something else I will have to read up on. I know BMW had trouble with high sulphur fuel with some Nikasil engines in the USA and that the LL-01 spec was related as well.