POV on oil analysis / viscosity

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Hello folks...

Just had my second analysis done at Blackstone.

Car is a BMW 1 series, with a 2.0L diesel engine (Engine type : N47)

The thing is, that iron is somewhat high, thou it matches the universal avg.
I assume that most owners just stick to the recommended 5w/0w-30, but as you can see, the viscosity is a bit low, probably because of DPF regen. every 250-400km (thats normal for this engine)

What i was thinking, was going for a thicker GC 5w-40 (13.9 cst at 100c). The GC 0w-30 i use now, is 12.2 cst at 100c......Will this combat iron maybe ?

Any comments/advise ??

blst.jpg


RGDS
LK
Denmark
 
First, forget about the universal averages that B/S lists. They are based upon what B/S has in their database and who knows the mileage of each sample.

With a iron of 50, TBN of 2, and fuel at 1% your oil is close to being used up. I would not go past 10K km.

You should have soot as a measured value. Polaris/OAI does.

With the way they are doing diesel engine pollution control these days, you are bound to get fuel in the engine oil. I think most people with recent diesel engines will be doing oil changes based solely fuel dilution.
 
Thanks Donald...

I agree with you...
I can actually see oil level rising a bit over time, because of blow by, and the engine it self not using any oil.

I therefor only go 10.000KM on an oil change..... NO more!

Any comments on going for a thicker oil to combat a little low viscosity, or does'nt it matter, based on the wear i get ?


(I use german castrol 0w-30 now)

LK
Denmark
 
What condemnation limits have you set for the lube?

I would agree that you might be approaching some reasonable limit, but I'm curious as to what you have established for your limits?
 
Originally Posted By: dnewton3
What condemnation limits have you set for the lube?

I would agree that you might be approaching some reasonable limit, but I'm curious as to what you have established for your limits?


I dont have any limits at all. I just want to minimize wear, and need to find the best route to do that.

since iron is the only one a little high, is was just wondering if a thicker oil would help...

smile.gif
 
Originally Posted By: VTS16
dnewton3 said:
...since iron is the only one a little high, I was just wondering if a thicker oil would help...

smile.gif



I doubt it but if your operational cycle is pretty static, i.e. it will be roughly the same as it was on the 0W30 run, why not try a load of Edge 0W40 and see? Run it the same 9500 KM and have B/S run another test. Use the same filter, etc. but let the only variable be the oil. Using the Edge 0W40 vs some other brand/type will help show that it was the viscosity and not the formulation that helped (or didn't help, as the case may be). The run you posted hints that there are others to compare with. DIvide the iron ppm by the KMs to get an average then compare that average, as well as the actual number.
 
Originally Posted By: VTS16
Originally Posted By: dnewton3
What condemnation limits have you set for the lube?

I would agree that you might be approaching some reasonable limit, but I'm curious as to what you have established for your limits?


I dont have any limits at all. I just want to minimize wear, and need to find the best route to do that.

since iron is the only one a little high, is was just wondering if a thicker oil would help...

smile.gif



How are you going to measure your efforts to "minimize wear"?

What I'm getting at is that you need to be concerned about two things:
1) wear rates
2) condemnation levels for the lube

Until you work on those concepts, you're just running around blindly.

As for the wear rates, you can start to look at these as you collect several UOAs, and then you'll have some fundemental starting point to know what seems reasonable for your vehicle. That is just the very tip of the beginning of getting micro data analysis started.

I know nothing about the little diesel you have, and I doubt Blackstone has many UOAs on it. You need to find some kind of database with some reasonable quantity of information so you can judge how you compare in a marco sense.

As for condemnation levels, there are some reasonable estimates we could make; Fe at 100, Cu and Pb perhaps 35, Al and Cr perhaps 25? Fuel would be maybe limited to 3%; same for soot? I don't know about the engine; you might have to seek out some levels, as mine are only wide and wild stabs based upon other marques, in a general sense.

What I'm trying to impress upon you is that getting the "lowest" numbers in a UOA is pretty much meaningless, because you can always manipulate the OCI/UOA to bias the results. Further, looking at singular UOAs can never give you a true picture of what is "better"; there is simply not enough data to base any fair conclusion upon. Normal variation will create enough "noise" in the results that any decision you made would be based upon a false sense of performance.

What you need to do is establish some criteria for your quest:
Set an OCI and stick with it. (Using the OEM OCI is never a bad starting point.)
UOA at those OCIs for a while to establish ranges and trends.
Stick with one lube/grade/filter for the testing; minimize the input variables.

Then you can see what your wear rates are, and hopefully compare/contrast them to other similar vehicles with this engine series. Once you establish how your vehicle is running and performing, you can then look at extending OCIs, and/or trying different products.

Please read my normalcy article; it may help you understand how/why to use UOAs.
 
Last edited:
Originally Posted By: Donald
First, forget about the universal averages that B/S lists. They are based upon what B/S has in their database and who knows the mileage of each sample.

With a iron of 50, TBN of 2, and fuel at 1% your oil is close to being used up. I would not go past 10K km.

You should have soot as a measured value. Polaris/OAI does.

With the way they are doing diesel engine pollution control these days, you are bound to get fuel in the engine oil. I think most people with recent diesel engines will be doing oil changes based solely fuel dilution.


Blackstones do have the average OCI figure for their universal averages, you do need to ask them what that figure is to make a comparison. The UOA looks good and with the TBN at 2 I would call it quits at 10K.
 
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