Different Labs have Different Standards?

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1,303
Location
Lexington, NC
I've been using WIX (ALS) for sometime now and when the viscosity (cST 100c) numbers hit 11.1, 11.4, 11.6, (2000 to 4000mi) and 10.6 (at 4000mi) I get yellow caution flags. The 10.6 had the comments of "change oil and filter if not already done so". Another rider of the same identical machine sends his 6000 mile sample to Blackstone, gets a viscosity of 8.3 (down in 20W) and a comment to try the next run to 8000 miles! There have been at least one other similar report done by Blackstone at 6000 mile with the comment that the oil was still ok. Metals and contaminants in all these reports were "normal". Question is, how can two labs be so far apart in judgement? I'm confused! My 10.6 and the 8.3 above were done on Can Am's new ACE 1330cc motor (3 cyl, shared sump) which the company says is good for 9300 miles between changes. Unless I get some convincing evidence otherwise, I'm going to change my oil at no more than 4000mi, maybe sooner.
 
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40,743
Location
Great Lakes
What you really should be comparing is the delta between virgin viscosity and used viscosity since different oils have different starting viscosity, even if they're classified in the same SAE viscosity grade. Example: Xw-30 oil with a starting viscosity of 10 cSt @ 100C. If UOA shows that it thickened up to 10.6, well, that's not a whole lot of change. Now if it had thickened up to 12.5, that's quite a bit more. Example 2: Xw-30 oil with a starting viscosity of 12.2 cSt @ 100C. If UOA shows that it's now 12.5, well that's not really so bad, is it? But as far as Blackstone and their so called "judgement", well, I don't exactly get it either. They seem to have invented their own viscosity ranges which do not line up with SAE J300.
 
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47,800
Location
Everson WA - Pacific NW USA
Blackstone comments. For entertainment purposes only. All in good fun. Their elemental analysis numbers, in particular the semi-metals (Ca, P, Na, Si, B, etc) have really tightened up in the last several years.
 
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15,881
Location
NE,Ohio
Depends on how you run your engine. If you push it alot a low viscosity could be troubling. Cruising around is different from pushing it in the hills.
 
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17,301
Location
OH
Yes, different labs have different ideas as to what's acceptable. Polaris will flag things that Blackstone won't. Blackstone will advise longer runs at TBN levels that Polaris will flag, for example.
 
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40,743
Location
Great Lakes
Originally Posted By: fdcg27
Blackstone will advise longer runs at TBN levels that Polaris will flag, for example.
Another example is TAN. Wearcheck will condemn any sample where TAN exceeds TBN, whether right or wrong. Blackstone will not do that. Not sure Blackstone ever looks at the relationship between the two.
 

tc1446

Thread starter
Messages
1,303
Location
Lexington, NC
Thanks folks for the feedback. I get the feeling that the reports I'm getting from ALS are reasonable, so I will continue to heed their advice.
 
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