I'm not reading all that, but no, thicker oil will not help. The pin is soft, and rollers eat into it. I have posted about this before. One thing though.... there are not that many failures when u consider how many are out there. Drive it and dont worry about it
Can thicker oil prevent rocker arm failures in Pentastar 3.6 V6?
- Thread starter easym
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Shear, not sheer. Sheers are curtains.
SAE J300 defines the minimum HT/HS for different grades. Reading your post I think you need to start further back in your understanding:
https://www.machinerylubrication.com/Read/31956/understand-oil-viscosity
That ship has sailedCareful there. You will be accused of being in the spelling and grammar Gestapo.
5w-20 has a better base with less VII plastic and that would be better for shear with the same running viscosity. VII has a limit they expand and HTHS goes beyond the limit.
What limit?
Also highly dependent on the base stock composition and the quality of the viscosity index improver used in the particular product.
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Yup, exactly.
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Deleted member 89374
Viscosity Improvers are kind of a big deal. A company like ExxonMobil Chemical makes its own. So does Castrol for specific blends. Castrol patented their best Viscosity Improver, and you can find the patent number on Castrol EDGE EP gold jugs and bottles, for example. Most petrochemical manufacturers make Viscosity Improvers. However, they are not all the same. Not even close. You can trust a good quality motor oil that uses high-quality Viscosity Improvers to stay in grade. Other oils will not, that's why there are so many discussions about oils shearing. And then there are motor oils like Mobil 1 FS 0W-40 that are designed to barely be a forty-grade due to fuel efficiency and cold-climate concerns.
I thought we were talking about an HT/HS limit for a particular grade. There is no real “limit” associated with VII functionality. Actually they work at all temperatures.
Even the best VII that do not permanently shear will have a expansion limit. And VII will have a temporary lower viscosity affect at MOFT. It is best to use base oil with a high VI.
The high quality base oil in this video is no VII at all but falls off to parallel at 100 C. That is some really good base oil to make 10w-40 with no plastic. In reality if we are talking about comparing 5w-20 to 0w-20 and the 5w-20 is a good synthetic that would be my choice for HTHS. Oil shears when there is plastic. That is if we are talking about 20 grade. But you get my drift being one of the smart guys here.
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Deleted member 89374
How do you know?
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Deleted member 89374
I talked to a Red Line Oil technician about this subject. I have also seen plenty of UOAs of the lubes I just listed. They are very stable. Oh, and I use them
This guy better be using some high viscosity clipper oil for that "High Sheering" action.
Well it’s going to be dependent on engine design and measurement tolerances as to whether any particular oil displays a viscosity deviation attributable to mechanical shear in a UOA. But in general any oil with VII can show a deviation due to shear. Only a monograde oil will be immune to mechanical shear in an ICE.I talked to a Red Line Oil technician about this subject. I have also seen plenty of UOAs of the lubes I just listed. They are very stable. Oh, and I use them
Plus on here most of the UOA showing a viscosity deviation can be attributed to fuel dilution, so it’s actually pretty hard to tell if an oil is shearing.
How the oil shears and loses viscosity due to the VIIs being chopped up vs what the HTHS viscosity is at 150C are somewhat separate things. There's a difference between permanent shear and temporary shear. A xW-20 will pretty much always have a lower HTHS viscosliy than a xW-30.
HTHS viscosity is HTHS viscosity ... regardless of the base oil or formulation of the oil.
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