Is Shearing and Oxidation happening at the same time?

OVERKILL said:
Keep in mind, there are a variety of different VII polymers used and they vary in their shear resistance from "shear easily" to basically not at all.

Base oils also oxidize at different rates; have different levels of oxidation resistance and antioxidants are used to reduce the propensity to oxidize.

Formulators do indeed try and balance visc loss through shear with oxidation, and, as @userfriendly noted, light ends flashing off, which varies depending on the base oils used. However, a bigger factor in recent years, since the introduction of DI, has been fuel dilution.

This is what happens when you use shear stable VII's with PAO as the dominant base in an application that doesn't fuel dilute (sample 2 is VOA):
View attachment 278655
Click to expand...
Thank you. That oil became thick instead, 8.5 to 9.5. Now this is another problem, oxidation winning and there is no shearing to stop it. This is not cool. I got excited that No VII oils remain at virgin viscosity all the time but apparently it is not the case. What oil is this?
 
Motor oil rookie said:
Thank you. That oil became thick instead, 8.5 to 9.5. Now this is another problem, oxidation winning and there is no shearing to stop it. This is not cool. I got excited that No VII oils remain at virgin viscosity all the time but apparently it is not the case. What oil is this?
Click to expand...
No VII oils do not remain at virgin viscosity, they thicken in use. This is not a no VII oil, this is the HPL "overkill" Super Car 0W-20, which has very little VII, and the VII it does have, are the incredibly shear resistant star type, which, as you can see, leads to viscosity only going one direction: up.

Now, this isn't a problem, a bit of oxidative thickening, but it's 180 degrees from what we normally see on here, which is viscosity loss in service.

I have another UOA/VOA combo that shows the Super Car 0W-40 compared to the Ravenol SSL 0W-40 in my SRT, the Ravenol sheared considerably, while the HPL sheared only a small amount. Of course a 0W-40 has more VII than a 0W-20.
 
OVERKILL said:
Keep in mind, there are a variety of different VII polymers used and they vary in their shear resistance from "shear easily" to basically not at all.

Base oils also oxidize at different rates; have different levels of oxidation resistance and antioxidants are used to reduce the propensity to oxidize.

Formulators do indeed try and balance visc loss through shear with oxidation, and, as @userfriendly noted, light ends flashing off, which varies depending on the base oils used. However, a bigger factor in recent years, since the introduction of DI, has been fuel dilution.

This is what happens when you use shear stable VII's with PAO as the dominant base in an application that doesn't fuel dilute (sample 2 is VOA):
View attachment 278655
Click to expand...
Thank you. That oil became thick instead, 8.5 to 9.5. Now this is another problem, oxidation winning and there is no shearing to stop it. This is not cool. I got excited that No VII oils remain at virgin viscosity all the time but apparently it is not the case What oil is this?
OVERKILL said:
No VII oils do not remain at virgin viscosity, they thicken in use. This is not a no VII oil, this is the HPL "overkill" Super Car 0W-20, which has very little VII, and the VII it does have, are the incredibly shear resistant star type, which, as you can see, leads to viscosity only going one direction: up.

Now, this isn't a problem, a bit of oxidative thickening, but it's 180 degrees from what we normally see on here, which is viscosity loss in service.

I have another UOA/VOA combo that shows the Super Car 0W-40 compared to the Ravenol SSL 0W-40 in my SRT, the Ravenol sheared considerably, while the HPL sheared only a small amount. Of course a 0W-40 has more VII than a 0W-20.
Click to expand...
I don't like this then. First 2000 miles on a regular 0W-30 will be 0W-30 and then becomes a thick 0W-20 after that. Here it is the other way around, oxidation makes the 0W-20 a thin 0W-30 in the last couple of thousand miles. In both cases I risk damaging my 3.6L Pentastar Upgrade(PUG) with that has a sophisticated valvetrain.
 
OVERKILL said:
Keep in mind, there are a variety of different VII polymers used and they vary in their shear resistance from "shear easily" to basically not at all.

Base oils also oxidize at different rates; have different levels of oxidation resistance and antioxidants are used to reduce the propensity to oxidize.

Formulators do indeed try and balance visc loss through shear with oxidation, and, as @userfriendly noted, light ends flashing off, which varies depending on the base oils used. However, a bigger factor in recent years, since the introduction of DI, has been fuel dilution.

This is what happens when you use shear stable VII's with PAO as the dominant base in an application that doesn't fuel dilute (sample 2 is VOA):
View attachment 278655
Click to expand...
You ran that oil for 6,800 miles though. If you stopped at 4000 miles or 5000 miles, it would remain closer to virgin, right?
 
OVERKILL said:
No VII oils do not remain at virgin viscosity, they thicken in use. This is not a no VII oil, this is the HPL "overkill" Super Car 0W-20, which has very little VII, and the VII it does have, are the incredibly shear resistant star type, which, as you can see, leads to viscosity only going one direction: up.

Now, this isn't a problem, a bit of oxidative thickening, but it's 180 degrees from what we normally see on here, which is viscosity loss in service.

I have another UOA/VOA combo that shows the Super Car 0W-40 compared to the Ravenol SSL 0W-40 in my SRT, the Ravenol sheared considerably, while the HPL sheared only a small amount. Of course a 0W-40 has more VII than a 0W-20.
Click to expand...
Is it this oil? Pricey but still less than going to the dealer and Jiffy Lube.
I will feel kind of bad to drain this out every 4000 miles but I will tell myself I am going to Jiffy Lube and spend $100 there.

Screenshot_20250511_093318_Chrome.webp
 
Motor oil rookie said:
I don't like this then. First 2000 miles on a regular 0W-30 will be 0W-30 and then becomes a thick 0W-20 after that. Here it is the other way around, oxidation makes the 0W-20 a thin 0W-30 in the last couple of thousand miles. In both cases I risk damaging my 3.6L Pentastar Upgrade(PUG) with that has a sophisticated valvetrain.
Click to expand...
You definitely do not risk damaging your Pentastar with a 0W-30, the tiny difference in viscosity at operating temperature is nothing compared to the huge swing experienced due to temperature. When I start my RAM at -30C, the oil is thousands of cP.
 
Motor oil rookie said:
You ran that oil for 6,800 miles though. If you stopped at 4000 miles or 5000 miles, it would remain closer to virgin, right?
Click to expand...
Yes, it thickens more the longer it is in service. I ran it even longer more recently, last OCI was 12,000 miles:
OVERKILL

Post in thread 'Post your latest oil change'

2019 RAM 1500 Sport - 5.7L HEMI

Engine mileage: 122,839km
Engine hours: 4,042 (614 idle)

Out: @High Performance Lubricants Super Car "Overkill" 0W-20, FRAM Titanium FS2
In: @High Performance Lubricants Super Car "Overkill" 0W-20, FRAM Titanium FS2

OCI length: 19,733km (12,261 miles)
OCI hours: 719

Oil added: none

IMG_7016.webp


This is my last FRAM Titanium kindly gifted by former member Rod Knock, so I've got two EaO's and then I'm into my stash of OG Ultra's, of which I have 9.
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I did not grab a sample, but I expect it was probably up closer to 10cSt.
 
Motor oil rookie said:
Is it this oil? Pricey but still less than going to the dealer and Jiffy Lube.
I will feel kind of bad to drain this out every 4000 miles but I will tell myself I am going to Jiffy Lube and spend $100 there.

View attachment 278660
Click to expand...
Yes, that's the oil. Dave blended it up for me, it's a full-SAPS additive package blended into a 0W-20 base. This means higher TBN and more AW additives than permitted for the API/ILSAC standards.
 
EvoMan said:
@OVERKILL In the example I posted below, (not my bike), the oil is a 20W-50. After 5,000 miles, which is what Harley says is a normal OCI, the ending viscosity was 23.87, which makes it a 60 grade. Is this something to be concerned about?

O

Thread 'Mobil1 V-Twin 20/50 2008 HD'

25,000 on 2008 FLHX. 5k on oil. Other sample on chart is Syn3

[img:center]
mobil.jpg
[/img]
Click to expand...
No, I wouldn't be worried about that.
 
Changing oil on my Jeep is a piece of cake. It is way up in the air and no jack needed. Oil filter is in the engine bay. By not going to Oil change places, not I will save money to buy premium oils but I will also do a better and cleaner job. They will over tighten my oil filter and overfill the oil, spill oil in the engine bay and charge me $125 for that pathetic job. Not to mention their low quality oil. I invested in a torque wrench, the required sockets and a cardboard to lay under the Jeep. That's it

Screenshot_20250511_173324_Gallery.webp
 
They are so busy that I'm pretty sure they wait for no longer than 5 minutes for the oil to drain out. No wonder oil is overfilled
 
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