Messing around with mixing - viscosities...

[userfriendly]

On the HDEO side of the equation, mixing a little SAE 40 in with 10W30 could result in a nice 15W30 with HTHS around 3.7.
Mixing SAE 30 into 15W40, same thing, except 15W40 HDEOs are easier to find than 10W30s and often cheaper.
In these examples, you are not playing with the VII affect, especially with multi-grade synthetic blends.
Would 0W40 + 15W40 = 20W50? That is the question. Non-linear VII affect, interesting concept. Almost game theory.

 

[SonofJoe]

Originally Posted By: Shannow
Here's what I recieved from another oil formulator when asking the same question...

Quote:
It's an interesting one. Certainly no guarantee of 0W being achieved but without knowing the oils it's difficult. Often PPDs are universal across an additive suppliers range. But if you had two oils with different DI, PPD and VII you might cause problems with used oil. Even if Ccs is ok for 0W

MRV can also run into problems when certain VMs are combined with other PPDs.



This person was probably taking about high ethylene VII polymers (typically, the Paratone VIIs sold by Oronite). Finding the right PPD to get MRV response (especially the yield stress component of the test) with these crystalline polymers can be problematic, especially if you have a lot of VII present (like in a Group I 10W50 for example). However, whilst you do need to take care, the problems are always fixable.

I would add three things on this...

First, virtually all commercial oils are way over-treated with PPD. This comes about because whilst, in theory, you might need only 0.01 wt% PPD to get a minimum passing MRV, commercial lube blending plants can't really cope with handling such tiny amounts, so this will typically get rounded up to 0.1 to 0.2%.

Secondly (and this only applies to the US ILSAC grades), since GF-4, it's a requirement to have a passing MRV on the used, end-of-test oil from the Sequence IIIG test (the so-called Sequence IIIGA). This too has led to formulators purposely over-treating the fresh oil with PPD.

If you mix two on-grade oils, one based on high ethylene OCP VII and the other based on the more common amorphous OCP, and both oils are on-grade for MRV (including yield stress), then 'dilution is a solution' as mixes of high & low ethylene OCPs tend to be more responsive to PPD.

 

[SonofJoe]

Originally Posted By: userfriendly
The topic of NOACK has not been mentioned in this thread. Not so much for the HDEO crowd, but in engines that are sensitive to formulations that might lead to LSPI, oil burning with the light grades, excessive piston deposits and stuck rings.

In Shannow's example, the same question of mixing; it sounds like the baby was thrown out with the bath water when A was added to B.

Look what happened to Richard Pryor when he mixed homogenized milk with skim. When left it in the fridge overnight, the two separated with the skim milk on the bottom.



If you want to get all scientific, blending Noack is fiendishly complicated because you are in effect blending vapour pressures of two multi-component mixtures. However given that most commercial oils have Noacks in a very limited range (say 7 to 15%?), then if you blend Noack linearly, you won't be far wrong.

I did do a lot of regression analysis on Noack. Typically the r-squared numbers would be a tad worse than for things like viscosity; maybe 0.985-ish?? However I came to the very simple conclusion that you just can't 100% predict a value that is subject to so much measurement error. The reproducibility of Noack is something like + or - 1%!

I take your point on LSPI. As you know, I'm something of an LSPI sceptic, but even so, I might think twice before blending up my own TGDI oil.

 

[Shannow]

Thanks for the great insights Joe !!!

 

[SR5]

Originally Posted By: SonofJoe
When I first transferred into Crankcase, ......

The analysis said that base oils, light or heavy, conventional or synthetic, Dispersants, Detergents, Antioxidants, ZDDP, etc all basically behave just like other hydrocarbons (ie units of -CH2-). VIIs are slightly different but as long as you de-couple their high temperature viscosities from their low temperature viscosities, they too blend all very logically.

If you blend two oils with a similar W-rating (say both have a CCS-35 of 6000 cP) but different oil weights, you will always get an oil with the same W-rating (and CCS-35 of 6000 cP) and the mixed oil KV100 will be somewhere between the KV100 of two original oils. The viscosities always blend on ln basis.

If you blend a monograde SAE 30 with a VII laden multigrade 0W30, and both oils have a KV100 of say 11.0 cst, any resultant mix will also have a KV100 of 11.0 cst but the KV40, CCS & HTHS will all change.


And thus, the new Golden Era of mixing, already blended oil, was started on BITOG.

Time to turn my garage into a Tiki Bar.

 

[userfriendly]

I think you are on to something there. People could bring their own containers, weigh them empty and charge by the kg or lb when they leave.
Twenty or so different engine oils on tap, plus 3 or 4 GL-5s with pumps and meters with prices and pay at the pump like fuel would also work.
Today I will take 5 liters of 0W40 and 15 liters of SAE 50 HDEO for a synthetic blend 20W50.
In my GL-5 pail, 5 liters of 75W140 and 15 liters of 80W90 for a nice 80W110 grade.
For the thin oil crowd, 50/50 SAE 10 and 0W20 = 5W16 syn blend.
The concept would reduce plastic waste and we could have a new topic category, or at the very least "post your last blend".

 

[Shannow]

Sort of what I suggested the other month

https://bobistheoilguy.com/forums/ubbthr...d_y#Post4416899

 

[SR5]

The house secret cocktail:
dash of M1 EP for the PAO content
jigger of Kendall GT-1 for the Titanium add
dollop of Pennzoil Platinum for GTL content
half a finger of Valvoline VR-1 for the zinc add

Shake and strain, garnish with a Fram Ultra.....

 

[fdcg27]

Originally Posted By: Shannow
Sort of what I suggested the other month

https://bobistheoilguy.com/forums/ubbthr...d_y#Post4416899


You did suggest that we might just aggregate our oil stash in a large container on an ongoing basis.
I personally dismissed your idea in that thread.
Maybe you were actually right in suggesting that this would be a safe and workable practice after all.
Your notion of continuously updating the add pack as you went did make some sense and we now know that we have little to fear in mixing oils dissimilar in brand or grade.

 

[Dallas69]

As I've said for years,mix away my friend.
I have no scientific background, just real world experience.

 

[Ducked]

Blending with a straight weight should eliminate the risk of unexpected VII interactions, which, as I understand it, is the main argument against blending multigrades.

What, if any, are the remaining potential gotchas?

 

[userfriendly]

Possibly NOACK, BOI and completion for surface mixing FM'd PCMO with HDEOs.
Royal Purple & green Kendall could = black.

 

[SilverFusion2010]

I just can't do it. Intentionally mixing different oils just makes me twitch. Why not select the correct oil for the application in the first place?

For those of you trying to use up the odd quart here and there, please ignore this post. I get it, saving some moola matters.

To me, trying to outsmart oil blenders as a bunch of armchair tribilogists is ludicrous. I really don't understand it. You're going to end up with a question mark for your viscosity and add pack, yet out of pure ego the thought is you have somehow "perfected" your blend. There are so many fantastic oils available... WHY?!?!?!?!?!?!?

I'm going to go cry for the sad state of humanity for a moment, then have another beer.

 

[Ducked]

Originally Posted By: SilverFusion2010
I just can't do it. Intentionally mixing different oils just makes me twitch. Why not select the correct oil for the application in the first place?

For those of you trying to use up the odd quart here and there, please ignore this post. I get it, saving some moola matters.

To me, trying to outsmart oil blenders as a bunch of armchair tribilogists is ludicrous. I really don't understand it. You're going to end up with a question mark for your viscosity and add pack, yet out of pure ego the thought is you have somehow "perfected" your blend. There are so many fantastic oils available... WHY?!?!?!?!?!?!?

I'm going to go cry for the sad state of humanity for a moment, then have another beer.

Yeh, see your point. I sort-of got lured into it by accidental degrees.

Started by topping up Delvac 15W/40 with Delvac straight 40, rationale being I had a bit of straight 40 left over which came with my previous car (Ford Sierra 2L DOHC) but not enough for a whole oil change, and I figured it would compensate for shearing, not much of an issue with the car but might be with the Kymco Zing motorcycle I also had at the time.

Then I bought some China Petroleum Corporation straight 40 to use in a 2-stroke Yamaha RZR gearbox.

Then I had a massive oil leak after removing the sump on the car which I mistakenly assumed was the sump gasket, and by the time I fixed it I'd replaced about half the sump volume with straight 40.

So now I'm here, there seem to be some potential advantages.

I'd quite like to just run a straight weight oil, for the well-known reasons, and I'm pretty sure a straight 40 would be OK (seemed OK in the Sierra which had hydraulic tappets) but the charts show straight 30 for local temperatures, and I havn't seen straight 30 or 10W/30 here. Cutting the straight 40 a bit with the Delvac 15W/40 sort-of addresses that issue.

Mobil publish bugger-all on the Delvac 15W/40 but various indirect sources suggest its good stuff, but might be a bit "rich" for my car, having a lot of dipersant/detergent and a high TBN. The CPC stuff OTOH, has a low TBN, so they might complement one another fairly well.

Whether I'll repeat the accident deliberately when and if I eventually do an oil change, I dunno, but I don't find the idea especially shocking.

 

[fdcg27]

While I agree with you I do find it reassuring to learn that I can safely dump in that odd quart with no worries as well as having no concerns about top-off oil used where needed.
I have no intentions of freely mixing brands and grades just because I apparently can, but it is good to know that I can use those odd quarts without any real concern.

 

[Triton_330]

Originally Posted By: userfriendly
A 50/50 blend of SAE 0W40 and SAE 30 would have a treat rate of 5.8% VII.
BOV would be 17% X #4 , 20% X #6 and 50% of the BOV of your SAE 30, likely an ISO 68 grade @ 40C.

Einstein would say something like 0W40 + 30 = 15W50

Okay, I read this whole thread through and through, and understand about 2/3 of it, but I am still confused [about that of which I quoted of you]...

I honestly cannot tell if you are joking or not. Would a 50:50 mix of 0w-40 + SAE30 actually equal 15w-50?

 

[userfriendly]

Shannow was theorizing a non-linear VII action. If true, 0W40 + SAE 30 could equal more than the sum of each divided by two.
Sonofjoe, in a round about way, said nice try guys.

Back on Earth, 0W40 + SAE 30= 10W40, or somewhere there about.

 

[SilverFusion2010]

Wait a minute. This is earth??? I knew I missed a turn back there...

 

[userfriendly]

To witness this sort of exchange in NA, you have to be up all night. See the post times. The sun never sets on the Empire.
The morning sun is hitting the top of BIG Ben and setting on the Sydney Opera house at the same time.
And then, just when the sun is coming up in Canada .... I'm hit with illogical fallacies, A Prisoner's Dilemma & Nash Equation and the effects of VIIs on mono-grade engine oil.
Then I get reprimanded for not using brackets; (R+M)/2=octane in NA.

 

[Ducked]

Originally Posted By: userfriendly
Possibly NOACK, BOI and completion for surface mixing FM'd PCMO with HDEOs.
Royal Purple & green Kendall could = black.


Why/how NOACK?

Taking it as a synonym for volatility, assuming that's a BAD thing, but assuming the individual components volatility is acceptable, what kind of negative interaction could raise the mix volatility above that of either of the starting components?

I'd expect mix volatility to be slightly skewed towards the less volatile component.

I had to look BOI up, here

http://www.api.org/certification-programs/engine-oil-diesel-exhaust-fluid/~/media/files/certification/engine-oil-diesel/publications/appendix-e-rev-09-01-11.ashx

Pretty complicated, but I noted a couple of points.

(a) According to the Introduction, (adverse?) effects are likely to be obscured by the additive package.

(b) Substituting / mixing G1 and G2 oils requires testing. Since that's probably what I'm doing (The CPC is probably G1, the Delvac MX is probably G2, though I'm not sure about either) that's a fairly good reason not to do it.

I assume "completion" should read "competition" as in "competition for surfaces mixing FM'd PCMO with HDEOs". Thats not something that's likely to be predictable, and therefore another reason not to do it.

However, I don't THINK that's what I'm doing. I THINK I'm mixing a (fairly low quality) HDEO with a fairly high quality HDEO. I dunno if either are FM'd (I'd guess not) but I've used the former in m/c gearboxes with no obvious clutch-slipping problems.