Best SAE30 weight oil?

[userfriendly]

I believe you can drop a grade with mono-grades, such as SAE40 instead of 20W50, SAE30 instead of 10W40 and so on.
Traditional VIIs permanently shear as they age, but they also shear temporarily in use ( %TVL ).

The minimum HTHS of 3.7 for an SAE40 is doable with an SAE 30, but, because it would be at the top end of the SAE30 specification of 12.5@100C, it may thicken out of grade from contaminates.

Chevron's Delo 15W30 is said to have an HTHS of 3.7 and a very high specific gravity which says mono-grade to me.

Would the same apply to an SAE20 instead of 0W30?

Let's say the SAE20 had a HTHS of 2.8 and the 0W30 3.2, but in operation temporary shear reduced the 0W30's HTHS to 2.7, thinner than the 0W30 when it counts.

One step further down the viscosity scale, an SAE16 could have a thicker base oil viscosity and higher HTHS during operation than a 0W20.

Which answers your question. Am I a 0W20 believer? Naw, if its cold enough to require 0W-XX, I'm staying indoors.

 

[Garak]

I don't buy the argument about the market moving away from multigrades at all, and commented in the other thread. Whoever makes a monograde oil that can pass ILSAC requirements without blowing the R&D budget to heck and back (and make an oil unfeasibly expensive) might be a hero, or a magician.

 

[alcyon]

Originally Posted By: Kuato


And yikes, based on this chart I'd prefer a 10w30 to a straight 30 - things are still pretty thick
at 40°C in a straight 30...

[

Actually looks pretty good .Most 5W and 10 are about 78 - 82 at 40C, this SAE30 PYB at 98 looks to be comparable to a 15Wor 20W.. Tempting to me.

 

[Jetronic]

Originally Posted By: userfriendly
I believe you can drop a grade with mono-grades, such as SAE40 instead of 20W50, SAE30 instead of 10W40 and so on.
Traditional VIIs permanently shear as they age, but they also shear temporarily in use ( %TVL ).

The minimum HTHS of 3.7 for an SAE40 is doable with an SAE 30, but, because it would be at the top end of the SAE30 specification of 12.5@100C, it may thicken out of grade from contaminates.

Chevron's Delo 15W30 is said to have an HTHS of 3.7 and a very high specific gravity which says mono-grade to me.

Would the same apply to an SAE20 instead of 0W30?

Let's say the SAE20 had a HTHS of 2.8 and the 0W30 3.2, but in operation temporary shear reduced the 0W30's HTHS to 2.7, thinner than the 0W30 when it counts.

One step further down the viscosity scale, an SAE16 could have a thicker base oil viscosity and higher HTHS during operation than a 0W20.

Which answers your question. Am I a 0W20 believer? Naw, if its cold enough to require 0W-XX, I'm staying indoors.


the 3.2 HTHS of the 0w30 is including temporary shear. Without that, we're looking at the kinematic viscosity at 150°C from which you can calculate the dynamic viscosity or the HTHS viscosity without the actual shearing.

 

[KCJeep]

I ran the PYB SAE 30 for six months during my summer OCI in the Jeep. Only time I could tell the slightest difference from 10w30 was a couple times at the very end of the OCI when it dipped to 40 degrees or so overnight. A little noisy then.

 

[BrocLuno]

So a bit more digging and we have this:

And to quote G-Man "Maybe the oils companies do know what they are talking about when they put something like the following in the PDS for straight grades: "Valvoline SAE 30, SAE 40, and SAE 50 offer excellent protection to gasoline engines operating under high temperature and heavy-duty service (hauling trailers, boats or RVs for sustained periods)."

 

[Bgallagher]

Castrol has always been good to me for SAE 30.

 

[BrocLuno]

Yeah, looking at that too

 

[gfh77665]

Originally Posted By: BrocLuno
So a bit more digging and we have this:

And to quote G-Man "Maybe the oils companies do know what they are talking about when they put something like the following in the PDS for straight grades: "Valvoline SAE 30, SAE 40, and SAE 50 offer excellent protection to gasoline engines operating under high temperature and heavy-duty service (hauling trailers, boats or RVs for sustained periods)."


That chart and its accompanying statement just blew a whole bunch of "thin oil" advocates right out of the water. Of course they certainly won't admit it though, LOL.

 

[Oregoonian]

synthetic available.....among the majors (PP, M-1, QSUD, Castrol etc.)

 

[SR5]

Wow !! Very interesting chart.
Thanks for posting

 

[BrocLuno]

Actually, I blows bad on the multi's with a lot of VII's... The rule of thumb is to keep the viscosity range as close as possible, So a premium 15W-30 is more stable (and maybe better...) than a 5W-40.

I'll dig up some other stuff and post when I get home.

But, the bottom line for me, is that I'll use up what's in my stash over the next few years and then switch back to a straight 30. I do not have cold to deal with. I do have hot ...

 

[zeng]

Originally Posted By: BrocLuno
So a bit more digging and we have this:

And to quote G-Man "Maybe the oils companies do know what they are talking about when they put something like the following in the PDS for straight grades: "Valvoline SAE 30, SAE 40, and SAE 50 offer excellent protection to gasoline engines operating under high temperature and heavy-duty service (hauling trailers, boats or RVs for sustained periods)."


+1
Thanks for sharing.

 

[B320i]

Originally Posted By: BrocLuno
So a bit more digging and we have this:

And to quote G-Man "Maybe the oils companies do know what they are talking about when they put something like the following in the PDS for straight grades: "Valvoline SAE 30, SAE 40, and SAE 50 offer excellent protection to gasoline engines operating under high temperature and heavy-duty service (hauling trailers, boats or RVs for sustained periods)."


WHOA! Now that is a real "piece of evidence," as it were. Maybe I ought to redact my previous criticisms of at least some thick oils!

That image is a keeper

However, if a 10w is a real wear-inducer - what is it thinning out to when hot?

 

[BrocLuno]

The report this came from was quite lengthy. It does not disclose all the elements of each of the oils. I suspect that they are run of the mill oils approved for Mercedes automotive diesels at the time.

Our oils have improved some, especially the AW add-paks, so I would expect the curves to be somewhat better today. But there are still lots of diesels, small aviation and marine gas engines that do not recommend multis, and have first choice still being straight weights. These engines can be very costly to extract and repair, so they pay very close attention. I also understand that radial piston engines do not tolerate synthetics very well. This applies mostly to dino oils.

True PAO and Ester synthetics (Grp IV & V) act very much like straight weights with the advantage of better cold performance and better high temp performance as well as shear resistance. So the ones mentioned earlier in this thread (Amsoil ACD for instance) will act like a straight 30 as far as the curves go, as far as I can can tell.

Redline lists their racing oils as XXwt for the racers. But if you look at the fine print, they also rate them as say 10W-30 or the like. So they are dual rating their oils. I have long suspected that this behavior under stress (acting like a straight weight) is the real key to Redline's race success...

But it all does toss a wrinkle in the 0W-20 qnd 0W-16 crowds reasoning. Within the article (or another I was reading, I get confused...), the engineers were stating that they used the very nature of the multi's shearing down as way of reducing internal drag and helping fuel economy. They were banking on it. So a 0W-20 might be a 16 on average by the time all the mileage testing was through ...

I'm not going to call it oil-gate, but I will say that there is whole lot that is not being discussed... And the marketers are having a field day making up hyperbole about how great their oils compared to one another. But note: they are only comparing a 5W-30 to say a 10W-30 or something. To my knowledge, no one is testing straight 30's against say 5W-30's for upper cylinder wear...

 

[Garak]

Originally Posted By: gfh77665
That chart and its accompanying statement just blew a whole bunch of "thin oil" advocates right out of the water. Of course they certainly won't admit it though, LOL.

There is one problem, though, with both points. First off, a 10w is a monograde. Secondly, it would appear that there's a lot of wear with high temperatures and 10w. No one would use (or was supposed to use back then) 10w in high stress applications. When that viscosity had a lot of traction, there weren't a lot of reasonable alternatives.

And that's what's being lost in much of this thread. If we had oil choices from fifty years ago, of course, I'd be doing seasonal oil changes, with a monograde 30 or whatever in the summer, and some other kludge for winter, be it a 10w or a 20w-20 or a fire under my oilpan or kerosene in the sump.

And, that's the point of multigrades. We don't have to go back to that, nor worry about comparing an SAE 30 to an obsolete 10w and a questionable 10w-30.

 

[userfriendly]

I made an assumption a page or two back which Jetronic corrected.
Published HTHS includes temporary shear loss by the action of the VII.
When an oil ages and displays permanent shear, does that viscosity loss affect the HTHS?

 

[Shannow]

Yes,
the temporary viscosity loss is the difference between what the oil SHOULD be if the fluid was "Newtonian" and what it does under extremely high shear rates (couple thousand RPM in modern engines for main bearings).

Pick M1 0W40 for example
Using
This M1 0W40 PDS

KV40 is 75
KV100 is 13.5.

Using the Widman calculator, KV150 should be 5.78cst.

Using the density, and http://planetcalc.com/2834/ the SG at 150C should be 0.75, and so if the oil were Newtonian (had no temporary shear), the HTHS SHOULD be 4.3... (KVxdensity convert to Cp).

Interestingly, that 4.3 is about what a straight 40 would deliver...surprise, it's Newtonian.

The M1 has 3.8. which means that under high shear rate conditions, it shears to 88% of it's theoretical, Newtonian Viscosity, or 12% viscosity loss at high shear. (It would have a Harman Index of 0.88)...it DOES recover back to 4.3Cp when the shear rate drops.

(Citgo 40 monograde http://www.docs.citgo.com/msds_pi/C10005A.pdf has an HTHS of 4.3, and that would be the same at any shear rate...it's High shear viscosity is exactly the same as it's low shear...zero viscosity loss).

As to part two of the question, multigrades show a usual "rule of thumb" permanent viscosity loss that is half the KV 100 loss within a range of up to about 20% KV100 loss.

As per the infamous Joe Gibbs Shear test, it's within a "rulle of thumb" measure, albeit at an extreme torture test.

"Sheared down to a 20, but at least maintained a high viscosity index"

 

[AuthorEditor]

Take a look at what longhaul truckers are using, especially big companies with lots of trucks. You would think that if anyone would want maximum wear protection, they would. Is anyone running a monograde?

 

[Garak]

I don't think they commonly are. TiredTrucker isn't. Doug Hillary doesn't. At the trucking parts and service outfitters I attend on occasion, I don't see a lot of monogrades hanging around or being pushed on promotion in their sales literature.