I have a question about this list

jurko

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Since I posted this list on the other forum I started to have questions about what it all really means.
No tribology graduate here but interested in learning and how it all works.
5W-30.jpg

Am I understanding this correctly that if the final product contains higher content of VII also referred to as VM that said product is more susceptible to aging by mechanical shearing and therefore subject to more frequent OCI due to VM's being sensitive to shearing which disrupts the molecular chain?

On the other hand. Is the final product with lowest amount of VII less susceptible to mechanical shearing and therefore OCI could be extended compare to above?

Is the higher content of VII needed due to lesser quality of base oil and vice versa?
 
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One thing to remember is that engines are all different in terms of the mechanical shearing they may impose on the oil. My old 1MZ-FE has gear-driven camshafts so it is likely higher, but the 1NZ-FE in the ECHO does not significantly shear oil as far as I've seen in the few UOA I have done.

Also not all VII are the same either. SonofJoe (or his current name) has discussed that, some are better quality than others. So just having a list like you have above is only part of the story, the specific application and the specific lubricant are contributors to the equation.

Again for me that's why approvals are important. Some have stay-in-grade requirements that relate to this discussion. For me that's far more important than a chart of values derived from some formula that I have no idea is valid or not. But I know the approval tests are valid. I'm not smart enough nor properly educated to know if the "Gokhan Formula" is really illustrating some grand composite summation of properties that results in an overall ranking of oils. I'm suspicious of any such thing but again, I don't know enough to know.
 
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I am sure the base stock blend has lots to do with the added viscosity improver amounts. Plus the Xw-XX spread of the finished product.
 

jurko

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One thing to remember is that engines are all different in terms of the mechanical shearing they may impose on the oil. My old 1MZ-FE has gear-driven camshafts so it is likely higher, but the 1NZ-FE in the ECHO does not significantly shear oil as far as I've seen in the few UOA I have done.

Also not all VII are the same either. SoneofJoe (or his current name) has discussed that, some are much better quality than others. So just having a list like you have above is only part of the story, the specific application and the specific lubricant are contributors to the equation.

Again for me that's why approvals are important. Some have stay-in-grade requirements that relate to this discussion. For me that's far more important than a chart of values derived from some formula that I have no idea is valid or not. But I know the approval tests are valid. I'm not smart enough nor properly educated to know if the "Gokhan Formula" is really illustrating some grand composite summation of properties that results in an overall ranking of oils. I'm suspicious of any such thing but again, I don't know enough to know.
Thanks for your reply.
When you look at you UOA results, what criteria or numbers you look at to tell you if it sheared significantly or not?
 
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Thanks for your reply.
When you look at you UOA results, what criteria or numbers you look at to tell you if it sheared significantly or not?
For me it was just looking to see if it stayed in grade. One has to account for fuel dilution though and with Blackstone that's not always accurate.
 

jurko

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For me it was just looking to see if it stayed in grade. One has to account for fuel dilution though and with Blackstone that's not always accurate.
So you look at the used oil viscosity compare to virgin oil viscosity and make judgment based on that if it stayed in grade?
What % difference would cause alarm for you to shorten the OCI?
 
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So you look at the used oil viscosity compare to virgin oil viscosity and make judgment based on that if it stayed in grade?
What % difference would cause alarm for you to shorten the OCI?
Only if it had an excursion outside of the grade limits. But that's just me.
 
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Another factor is that the oil companies reformulate their oils to meet current standards. That list will be accurate for the moment but six months or a year from now, maybe not.

As already mentioned , approvals are the best way to choose a oil.
 

jurko

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Another factor is that the oil companies reformulate their oils to meet current standards. That list will be accurate for the moment but six months or a year from now, maybe not.

As already mentioned , approvals are the best way to choose a oil.
I agree about approvals. But if that was my only concern and nothing else I would have not become a member of this great community where members share their experience and knowledge about motor oil properties which I wouldn't otherwise know.
 
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I agree about approvals. But if that was my only concern and nothing else I would have not become a member of this great community where members share their experience and knowledge about motor oil properties which I wouldn't otherwise know.
Well, in this case the great BITOG community is reaffirming what you already believed - that mfg approvals are a great measure of performance. Everything else is highly speculative, but of course it gives BITOG something to talk about.
 

jurko

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Well, in this case the great BITOG community is reaffirming what you already believed - that mfg approvals are a great measure of performance. Everything else is highly speculative, but of course it gives BITOG something to talk about.
😊
 
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