I was surfing and I found this very informative article about oils. It explains Group I-V oils, dino, syn, semi-syn.

Not written by any vendor, just a guy who did a lot of research.

http://www.brainmaker.com/ST1300/Oils1.html

 

Thats a good article for someone like me who doesn't know a whole lot about the different types of oil.Most guys here know most of the information.This forum is great.I'm finding out a lot about oil that I never even considered in the past.Thanks.

 

I've read the article, as with a few other articles of this same nature.
So polymers are what make the oil multi-viscosity oil. My question..... Since an oil such as a straight 30w is not multi-viscosity, does it not have these non-lubricating polymers?

 

My understanding is that a straight weight oil, say SAE 30, does not have the polymers. It also would be limited in cold flow. For example, my Haynes Ford Truck manual says not to use SAE 30 oil below 40 degrees F ambient temperatures. This stuff would clog the oil pump on a very cold day, say maybe 20 F.

It also is my understanding that some synthetic oils acheive the multigrade rating without polymers because the oil already has a very high viscosity index. The lack of polymers (or minimized use of) probably is one of several reasons synthetics flow better in cold and hold up better in heat.

 

It's a good summary and I enjoyed reading about GTL (gas to liquid base oil). But it contains some inacuracy and misinformation.

The tables comparing the pour point of mineral oil, PAO and Diesters doesn't seem right. For instance it lists the pour point of Group II and III at +25 deg. F. and +20 deg. F. But I checked Chevron's data sheets and Group II 10w30 has a pour point of -31 deg. F. and Group III 10w30 has a pour point of -60 deg. F.

The article also seems to perpetuate the myth of 3,000 mile oil changes and the whole parafin/wax/sludge will kill your engine unless you use PAO or Diester base synthetic.

So while it does seem to contain some very good information, beware not to take everything it says as gospel.

 

It was written for motorcycles, so that may be the reason for the 3000 mile oil change.

The article does have some errors. Mobil 1 is a Group IV, I believe, not a Group III as stated in the article.

Delvac syn. is a Group III, not a Group IV.

The basic info, Group I-Group IV and additives, is very informative.

 

i thought it was a great article. i finally found what i was looking for . now i know of the flash point . ther you go i learn something new everyday

 

Only got to read three sections so far (refining, synthetics, and making multigrades) and I think it is pretty much right on. The table values of pour point do look wrong though. He overgeneralizes on the viscosity increase factors using SAE grades, but is is ball park. And he correctly (from what I have seen elsewhere) notes that a multigrade is better than a straight weight if the engine overheats (oil above 230 degrees). I disagree about the oil companies using cheap VIIs. Some may, but I suspect the premium oils use good ones.

 

Paul, I would be interested in looking over the sources of this information if you can recall who/what they are.

(FWIW, I'm just curious about it, that's all, I'm not taking you to task or anything... )

 

I bet I read it in Jim Fitch's book How to Select a Motor Oi and Filter (noria.com). I will check tonight and post what I can find. It also was his book that said not to use a straight weight if your engine overheats--I don't understand that, you would think the polymers would cook before a straight oil. Maybe I will pose that question to MolaKule at the oil guy site.

I am glad you put the FWIW. We all should be willing to take flack and perceived flack lightly on these boards since the posters may not mean it. I think few of us ever want to offend anyone, just clarify and ask good questions.

 

Permanent viscosity sheer down "is a non-issue for some Group V synthetics and only a marginal issue for Group III and Group IV base oils. Some synthetics don't use VII for 10w30, 15w40, 5w30, but do use them for 0w30. The exception might be a Group V ester synthetic which can reach a 0w30 unaided by VIIs."

From "How to Select A Motor Oil or Filter for Your Car or Truck," by James C. Fitch.

BTW, I have read this book three times and guess I will read it again. A hard copy is $5 more than an online copy, but the hard copy is nicer and has a beautiful front cover showing a hand removing an oil drain plug with the black oil running down the guy's arm.

 

so would i be ok with running that 5w40 syn rotella T in my truck? looks like a great oil.

 

Hi guys,

I wrote the article in question.

It was written very much with motorcycles in mind. Motorcycles generally run the engine oil through the transmission; this is hell on the VII package. I test the viscosity of oils regularly, and normal motor oil does not hold up in a motorcycle for more then 2500 miles. This statement is not true for cars - I run my engine oil in my (eh-hum) Brand "C" pickup truck for 7000 - 9000 miles.

The pour points listed are for pure base oils, and are correct. I work hard on my research - I'm a part-time graduate student in physics, bad research is simply not tolerated. The oils you buy are a blend of a lot of stuff, and normal multi-grade oils have typical pour points of -10 or so.

I stand by my statement that Mobil-1 is now primarily a group-III oil. Since the Exxon buyout and their lawsuit with Castrol, Mobil-1 has turned into just another group-III blend. It's still a good oil, and I don't hesitate to recommend it, but if you want a pure synthetic base stock you're currently limited to AMSOil and Motul-5100.

A straight 30 weight oil would have no VII package, no polymers to shear. This oil would be perhaps a good choice in the summer in a southern state, but a very poor choice if you think you might ever start your engine in temperatures under about 45 degrees.

Rotella is a fine choice for truck motors. Mobil-1 is about to release a 5w-40 oil for "SUVs" which I expect to also be excellent.

PAO and Diester based synthetics have a VII package. These base oils have a significantly higher VI than group I or group II oils, and require less of a VI package, but it's there.

VII packages definitely come in different prices and different qualities. Spiffo-Magic 10w-40 for $1.09/qt has a package which is very much inferior to the package in, for example, the group-II Rotella or Delvac 15w-40 oils. However, truck engines are really not all that hard on the VII package, this is considerably less of an issue than in a motorcycle.

I write and sell computer software; I manufacturer and sell aerodynamic accessories for motorcycles; and I maintain a motorcycle information web page http://MotorcycleInfo.calsci.com. I don't sell motor oil, and I don't sell truck parts or accessories. To the contrary, I buy my oil filters (Purolator Pure-One) by the case at Pep Boys, where I insist on a 25% case discount, and I buy my oil (Rotella 5w-40) by the case at Wal-mart, where asking for a case discount is about as effective as lecturing on Buddhism in Sanscrit in Saudi Arabia.

I run Rotella 5w-40 in all my motorcyles, my 5.3l truck, and my 7.4l motorhome.

 

Hi Mark! Thanks for joining us at FTE!

I was wondering about the pour point comparison in your paper. Would those numbers for mineral base oil be reflective of a Group I oil? Average pour points of -10 seems kind of high since I've gotten used to seeing product spec's with lower pour points. It seems that a Group II or III oil should have a much lower pour point, such as I quoted from a spec sheet in my previous post. It just didn't seem to be fair to compare the highest rated (IV, V) pure synthetic against the lowest rated (I) mineral oil.

 

I am not challenging you work, just trying to get accurate information. So please don't hate me.

I posted your article on another forum. Below is the response that I got from someone who has worked in the oil industry about 30 years, including a long stretch as an oil blender: