New Article of the Month by Dr. Haas

[Gary Allan]

Originally Posted By: Tempest
Quote:
A 10W-30 multi-grade mineral based oil is made from a 10 grade oil and has VI improvers added to thicken the product in a 212 F engine.

Wrong.




That is allegedly one way to make a 10w-30 ..and it may indeed been under standards that are in excess of 40 years old. It would be worthless for any length of service ..which most multivisc's were.

There's was a discussion between Stinky Peterson, G-Man, and a couple of others on this.

Stinky put it forth, then G-Man responded ..sure, then you discover PPD's and now you can use a 20 grade base stock and it will meet your cold spec's and use less VII (paraphrased) ....etc...etc.

I got the impression (and I've looked for the origins of the rating system in terms of "numeri'clature") that 10 "weight" (
This isn't the thread in question, but it contains the same assertion.
Here. Take a look

Quote:
There is a band or range of acceptable viscosity for each viscosity weight or grade at each temperature. Sometimes liquid lubricants meet both the lower winter and the higher summer viscosity requirements, and carry numbers such as SAE 10W-30. SAE 10W-30 means that at -18°C (0°F) the oil viscosity falls within the 10 weight band, and at 100°C (212°F) the oil viscosity falls within the 30 weight band. Such lubricants are called multi-viscosity lubricants, and are made by adding specially selected VI improvers to 10 weight oil.

 

[Tempest]

That assumes a mono base oil...which isn't usually the case. They will be a blend of some sort...not to mention additives and correction fluid.

The CRC handbook mentions the 10 grade plumped up to a 30 grade via VII, but again, that is with a single, unformulated base. This may be where he got this from.

Amsoil sells their ACD which is a "10W30" achieved with no VII. Their ATM (also 10W30) has much better cold characteristics and does not make the no VII claim. The idea that ALL or even MOST synthetic 10W30's on the market have no VII doesn't add up.

 

[Gary Allan]

Oh, no argument there. Blending of base stocks and tweaking is far more common than not. You can't get some places without it. Bruce's 0w-10 was a blend. He listed PAO and Group III. One would think that if any oil could be done with a single base stock ..that would be it. It was not the case.

 

[crinkles]

Originally Posted By: Mustang Man
Having read Dr. Haas' article a few times, it appears some of this started over blood...

http://www.focfloridaregion.com/edu/oil.htm

"When he was a general surgery resident in Chapel Hill he studied the flow mechanics of human blood."

He uses thin oil for better flow. Well, using blood as an example, if blood is too thin, you may develop Hemophilia which means the blood is too thin to clot and you can bleed easily. So using that logic to motor oil, if the oil is too thin it will not protect as well and may leak.

If blood is too thick, then Hypercoagulability happens. Blood will tend to stick to the walls of blood vessels forming Fibrin. Fibrin leads to clots. So in relation to motor oil, if it is too thick, I suppose it will form oil's version of Fibrin... sludge/varnish.


whether bood will clot or not is not as a result of being thick or thin, but whether there is the clotting agent present.

 

[Steve S]

Originally Posted By: Quattro Pete
Originally Posted By: Bruce T
The ambient temperatures do matter in oil grade selection,

Why? In a modern engine, you could run 0w-30 oil regardless if you lived in Alaska or Arizona.

That is why.