What makes HDEO more shear stabel than PCMO?
- Thread starter bchannell
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It's not true.
It IS true.
HDMOs are made with higher viscosity basestocks than a typical ILSAC PCMO. They can do this because they typically aren't chasing 5W, or 0W.
In addition, the US PCMOs typically have less shear stable VII polymers.
All adds up.
HDMOs are made with higher viscosity basestocks than a typical ILSAC PCMO. They can do this because they typically aren't chasing 5W, or 0W.
In addition, the US PCMOs typically have less shear stable VII polymers.
All adds up.
What shears in engine oils is the additive called Viscosity Index Improver, on its polymerization (isn't their molecules that hear off, just the poly-attachments on each other long chain).
Knowing this, if such HDEO is more shear stable than such PCMO you can bet such HDEO's have a better VII, than such PCMO.
Knowing this, if such HDEO is more shear stable than such PCMO you can bet such HDEO's have a better VII, than such PCMO.
People complain about Rotella T6 5w40 shearing in motorcycles
Yes, but in share sump/tranny/clutch motorcycle. Those chew up any oils, even synthetics, since what shears isn't base but VII, specially wide spread grade, like 5w40, 10w50 or even a 0w30 ... Now a 20w50 is so thick that the VII is also protected, to a degree.
Originally Posted By: Shannow
It IS true.
HDMOs are made with higher viscosity basestocks than a typical ILSAC PCMO. They can do this because they typically aren't chasing 5W, or 0W.
In addition, the US PCMOs typically have less shear stable VII polymers.
All adds up.
Originally Posted By: 901Memphis
People complain about Rotella T6 5w40 shearing in motorcycles
I have noticed the same thing in my bike. But this still points to what shannow said, when they have to make it a 5w it shears more. The 15w 40 rotella goes longer in my bike than the 5w40 rotella. I have not done uoas, but i can feel the shifts getting notchy as the oil shears down.
It IS true.
HDMOs are made with higher viscosity basestocks than a typical ILSAC PCMO. They can do this because they typically aren't chasing 5W, or 0W.
In addition, the US PCMOs typically have less shear stable VII polymers.
All adds up.
Originally Posted By: 901Memphis
People complain about Rotella T6 5w40 shearing in motorcycles
I have noticed the same thing in my bike. But this still points to what shannow said, when they have to make it a 5w it shears more. The 15w 40 rotella goes longer in my bike than the 5w40 rotella. I have not done uoas, but i can feel the shifts getting notchy as the oil shears down.
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Originally Posted By: 901Memphis
People complain about Rotella T6 5w40 shearing in motorcycles
It's a 5W40, and therefore contains quite an amount of VIII (in spite of it not being the conventional basestock that the OP posted).
Going back to the OP's question, and taking the fact that I don't think the US even HAS a 15W40 PCMO (common in other parts of the world).
The 15W40 will have a higher viscosity basestock than a 10W40, 5Ws30, or 10W30.
The 15W40 will have lower VII treat rates than the 10W40 and the 5W30, and probably comparible with the (obsolete to BITOGERS) 10W30.
So YES, the HDMO conventional WILL be more shear stable than a typical PCMO conventional...it just is a fact of it's composition.
People complain about Rotella T6 5w40 shearing in motorcycles
It's a 5W40, and therefore contains quite an amount of VIII (in spite of it not being the conventional basestock that the OP posted).
Going back to the OP's question, and taking the fact that I don't think the US even HAS a 15W40 PCMO (common in other parts of the world).
The 15W40 will have a higher viscosity basestock than a 10W40, 5Ws30, or 10W30.
The 15W40 will have lower VII treat rates than the 10W40 and the 5W30, and probably comparible with the (obsolete to BITOGERS) 10W30.
So YES, the HDMO conventional WILL be more shear stable than a typical PCMO conventional...it just is a fact of it's composition.
Originally Posted By: mrsilv04
Originally Posted By: spasm3
I have not done uoas...
So, you're passing off what is little more than speculation, as the truth?
OK, I'll play along. My turn. I have not done uoa's, but the gearbox in a 250 can actually shear oil?
Not as truth, as something I said I've noticed with my bike.
Thats why i said i have not done uoas. I can definitely feel the shifts get clunky quicker with the t-6.
The wet clutch shares the engine oil with the gear box. Its an air cooled engine so why would it not shear oil like any other bike.
Originally Posted By: spasm3
I have not done uoas...
So, you're passing off what is little more than speculation, as the truth?
OK, I'll play along. My turn. I have not done uoa's, but the gearbox in a 250 can actually shear oil?
Not as truth, as something I said I've noticed with my bike.
Thats why i said i have not done uoas. I can definitely feel the shifts get clunky quicker with the t-6.
The wet clutch shares the engine oil with the gear box. Its an air cooled engine so why would it not shear oil like any other bike.
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Originally Posted By: Shannow
It IS true.
HDMOs are made with higher viscosity basestocks than a typical ILSAC PCMO. They can do this because they typically aren't chasing 5W, or 0W.
In addition, the US PCMOs typically have less shear stable VII polymers.
All adds up.
Hate to burst everyone's bubble, but for a lot of blenders they use the same OCP Viscosity modifier for both PCMO and HDDEO - this is purely for logistical reasons. The more stable VM's typically end up in specialty grades like the 5W40's.
In some cases the blender might choose a more shear stable OCP for both, but it's not very common to have a separate VM for both HDDEO and PCMO.
It IS true.
HDMOs are made with higher viscosity basestocks than a typical ILSAC PCMO. They can do this because they typically aren't chasing 5W, or 0W.
In addition, the US PCMOs typically have less shear stable VII polymers.
All adds up.
Hate to burst everyone's bubble, but for a lot of blenders they use the same OCP Viscosity modifier for both PCMO and HDDEO - this is purely for logistical reasons. The more stable VM's typically end up in specialty grades like the 5W40's.
In some cases the blender might choose a more shear stable OCP for both, but it's not very common to have a separate VM for both HDDEO and PCMO.
Solarent, I will wear that, and not consider it a burst bubble, but WRT HDEO and PCMO shear stability in conventional oils, I don't think they are chasing 5W40 HDEO with conventional basestocks.
Here's one with a common ingredient
https://www.aftonchemical.com/ProductDataSheets/Engine Oil/HiTEC-5751_PDS.pdf
I'll still sit on the fact that the HDEO (15W40) conventional grade is more shear stable than the PCMO grades.
Here's one with a common ingredient
https://www.aftonchemical.com/ProductDataSheets/Engine Oil/HiTEC-5751_PDS.pdf
I'll still sit on the fact that the HDEO (15W40) conventional grade is more shear stable than the PCMO grades.
Originally Posted By: Shannow
Solarent, I will wear that, and not consider it a burst bubble, but WRT HDEO and PCMO shear stability in conventional oils, I don't think they are chasing 5W40 HDEO with conventional basestocks.
Here's one with a common ingredient
https://www.aftonchemical.com/ProductDataSheets/Engine Oil/HiTEC-5751_PDS.pdf
I'll still sit on the fact that the HDEO (15W40) conventional grade is more shear stable than the PCMO grades.
I agree 5W40 or even new 5W30 HDDEO - which we will see more of as PC-11 hits the market next December are usually with synthetics. If you go back and read some of my posts in the Viscosity Index Improvers are not Bad thread, I talked about different kinds of VM's and how they affect oils differently with relative shear stability and the concentration of VM in the formula.
The Afton OCP you link to has an SSI of 50 (this means the VM loses 50% of it's VM viscosity contribution). More shear stable options have much lower SSI numbers (like 35 or 25 for OCP's and as low as 5 for some of the other types). The thing about the more shear stable VM's is they tend to not thicken the oil as much so you need more to obtain the same viscosity increase impact. This is why VM concentration is not indicative of shear stability of the finished oil.
Solarent, I will wear that, and not consider it a burst bubble, but WRT HDEO and PCMO shear stability in conventional oils, I don't think they are chasing 5W40 HDEO with conventional basestocks.
Here's one with a common ingredient
https://www.aftonchemical.com/ProductDataSheets/Engine Oil/HiTEC-5751_PDS.pdf
I'll still sit on the fact that the HDEO (15W40) conventional grade is more shear stable than the PCMO grades.
I agree 5W40 or even new 5W30 HDDEO - which we will see more of as PC-11 hits the market next December are usually with synthetics. If you go back and read some of my posts in the Viscosity Index Improvers are not Bad thread, I talked about different kinds of VM's and how they affect oils differently with relative shear stability and the concentration of VM in the formula.
The Afton OCP you link to has an SSI of 50 (this means the VM loses 50% of it's VM viscosity contribution). More shear stable options have much lower SSI numbers (like 35 or 25 for OCP's and as low as 5 for some of the other types). The thing about the more shear stable VM's is they tend to not thicken the oil as much so you need more to obtain the same viscosity increase impact. This is why VM concentration is not indicative of shear stability of the finished oil.
Shearing comes from the viscosity index improver (VII) additive. Straight motor oils do not shear. The most shear stable in a VII class are the lower molecular weight versions. Drawback of those is they do not thicken as well and it takes more additive or what many call "rubber" to get to a heavier grade. Down side is more rubber = more deposits. Within VII classifications such as PMA, OCP, Star polymers, PIB; the lower the molecular weight, the better the shear stability. When you make a multi-grade oil you usually start with the "W" grade to set the base oil grade. You than add VII to make the non "W" portion. The wider the span 0W-50 compared to 15W-50 the more VII.
Originally Posted By: Solarent
Originally Posted By: Shannow
It IS true.
HDMOs are made with higher viscosity basestocks than a typical ILSAC PCMO. They can do this because they typically aren't chasing 5W, or 0W.
In addition, the US PCMOs typically have less shear stable VII polymers.
All adds up.
Hate to burst everyone's bubble, but for a lot of blenders they use the same OCP Viscosity modifier for both PCMO and HDDEO - this is purely for logistical reasons. The more stable VM's typically end up in specialty grades like the 5W40's.
In some cases the blender might choose a more shear stable OCP for both, but it's not very common to have a separate VM for both HDDEO and PCMO.
VM, like MoS2? or you meant VII?
Originally Posted By: Shannow
It IS true.
HDMOs are made with higher viscosity basestocks than a typical ILSAC PCMO. They can do this because they typically aren't chasing 5W, or 0W.
In addition, the US PCMOs typically have less shear stable VII polymers.
All adds up.
Hate to burst everyone's bubble, but for a lot of blenders they use the same OCP Viscosity modifier for both PCMO and HDDEO - this is purely for logistical reasons. The more stable VM's typically end up in specialty grades like the 5W40's.
In some cases the blender might choose a more shear stable OCP for both, but it's not very common to have a separate VM for both HDDEO and PCMO.
VM, like MoS2? or you meant VII?
Originally Posted By: Pontual
VM, like MoS2? or you meant VII?
Moly is a friction modifier, not a viscosity modifier.
VM, like MoS2? or you meant VII?
Moly is a friction modifier, not a viscosity modifier.
Sure, but everybody uses VII ...
I think what you said about PCMO & HDDO using the same high SSI VII (you can call it VM, it's the same stuff) might have been true in the past but not today.
The API CJ-4 HDDO specification contains the Kurt Oban 90 cycle shear test. XX-40 oils must stay in grade (ie, have a KV100 of 12.5 cst min) after 90 cycles of being mechanically sheared. This almost certainly means that the oils are formulated with shear stable 22 SSI OCP VII.
The other thing that you need to bear in mind is that HDDOs tend to contain more additive than PCMOs, particularly ashless dispersant to handle the soot you get in diesel engines. This tends to reduce the amount of VII you need which in turn reduces the tendency of the oil to shear.
If you're worried about shear on a motorcycle engine, where the engine and the gearbox share the same oil, them I might look for a specialised bike oil which carried some sort of API gear oil spec. Motorcycle oils aren't my thing so I can't recommend anything. However I could well imagine that there's some blender out there using non-shearable PIB as a VII to get the performance you are looking for. It will however cost far more than bog standard HDDO and PCMO....
The API CJ-4 HDDO specification contains the Kurt Oban 90 cycle shear test. XX-40 oils must stay in grade (ie, have a KV100 of 12.5 cst min) after 90 cycles of being mechanically sheared. This almost certainly means that the oils are formulated with shear stable 22 SSI OCP VII.
The other thing that you need to bear in mind is that HDDOs tend to contain more additive than PCMOs, particularly ashless dispersant to handle the soot you get in diesel engines. This tends to reduce the amount of VII you need which in turn reduces the tendency of the oil to shear.
If you're worried about shear on a motorcycle engine, where the engine and the gearbox share the same oil, them I might look for a specialised bike oil which carried some sort of API gear oil spec. Motorcycle oils aren't my thing so I can't recommend anything. However I could well imagine that there's some blender out there using non-shearable PIB as a VII to get the performance you are looking for. It will however cost far more than bog standard HDDO and PCMO....
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Originally Posted By: Pontual
Sure, but everybody uses VII ...
VII = Viscosity Index Improver
VM = Viscosity Modifier
Both are used interchangeably in the industry. Although technically Viscosity Modifiers could include other types of polymers that are used as PPD's (or pour point depressants)- I'm sorry if my post was confusing.
Sure, but everybody uses VII ...
VII = Viscosity Index Improver
VM = Viscosity Modifier
Both are used interchangeably in the industry. Although technically Viscosity Modifiers could include other types of polymers that are used as PPD's (or pour point depressants)- I'm sorry if my post was confusing.
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