How Do Viscosity Index Improvers Work?

Status
Not open for further replies.
Joined
Dec 9, 2013
Messages
3,083
Location
Alabama, United States
Look, I am more than certain this has been discussed many times over, but I think it's a subject that should be kept in current rotation. The easiest way to do that is to create a new thread about it. I also really don't know how they operate. So, in regular conventional multigrade motor oil, how do VII's operate?
 
Viscosity index improvers are long molecular chains made out of polymers that look like roll up ladders. When the oil is cold, the ladder is rolled up. When the oil heats up and gets thinner, the roll up ladder unrolls to counteract the oil's natural tendency to get thinner.

2017-factory-sale-Free-Shipping-10-m-High-quality-HOT-SALE-Emergency-roll-up-ladder.jpg
 
Originally Posted By: bullwinkle
Chevron has a good explanation here:
https://www.oronite.com/paratone/tempeffect.aspx


Fascinating.

"The VII polymer dissolved in oil takes on a coil form."

A guy on a tractor forum discussing 1960's diesels running on 15W-40 said it would kill the engine, because 15w-40 is filled with microscopic plastic beads that expand and thicken the oil when hot. He said older diesels designed to run straight 30 would shear/destroy all the little plastic beads in 15W-40 oil.
 
Originally Posted By: Red91
Look, I am more than certain this has been discussed many times over, but I think it's a subject that should be kept in current rotation. The easiest way to do that is to create a new thread about it. I also really don't know how they operate. So, in regular conventional multigrade motor oil, how do VII's operate?


https://bobistheoilguy.com/forums/ubbthr...ier#Post4137130
https://bobistheoilguy.com/forums/ubbthr...re_#Post3788899
https://passenger.lubrizoladditives360.com/vm-series-part-1/
https://passenger.lubrizoladditives360.com/vm-series-part-2/
https://commercialdevsite.lubrizoladditives360.com/vm-series-part-3/
 
Originally Posted By: Linctex
Originally Posted By: bullwinkle
Chevron has a good explanation here:
https://www.oronite.com/paratone/tempeffect.aspx


Fascinating.

"The VII polymer dissolved in oil takes on a coil form."

A guy on a tractor forum discussing 1960's diesels running on 15W-40 said it would kill the engine, because 15w-40 is filled with microscopic plastic beads that expand and thicken the oil when hot. He said older diesels designed to run straight 30 would shear/destroy all the little plastic beads in 15W-40 oil.



There are many sizes and shapes of molecules that are used as VII polymers. That guy on the tractor forum doesn't know what he is talking about.
 
Originally Posted By: Merkava_4
Anybody can post a link.

It's the guy that provides an explanation right out of his head that makes him D'Man !
cool.gif



LOL, do that, and they ask you for proof.

Provide proof, and you're posting "other people's work"...can't win on BITOG.
 
The Chevron Oronite link puts it in basic, understandable terms. If I'm interpreting correctly, the VII allows more flow at lower temperatures because it shrinks the oil's molecules, no?
 
Originally Posted By: Red91
The Chevron Oronite link puts it in basic, understandable terms. If I'm interpreting correctly, the VII allows more flow at lower temperatures because it shrinks the oil's molecules, no?

No. Nothing is happening with the oil. The oil stays the same and it is the polymer molecules that are changing size and volume which influences the viscosity.
 
OK, that's where I get lost. How does this manipulate viscosity? What are the polymers doing when they coil and uncoil that affects viscosity? That's what I don't understand.
 
Originally Posted By: Red91
frown.gif
Come on guys, I'm serious. I thought it was a legitimate question.


What ? You don't like my roll-up ladder analogy ?
laugh.gif
 
Status
Not open for further replies.
Back
Top