Thanks subdriver & jumcork1 for your info. As stated, I'm no oil guru & don't want to be. On base oil, I meant every oil starts at 0. The one thing I haven't been able to figure out is the groups. As you mentioned, most companies won't tell you, especially on their containers, & some may even lie about it to sell their product (won't mention any names). So how in hades do you know what you're buying. I've probably seen about every test of almost all oil manufacturers & believe it or not, their product always win.....amazing, isn't it. What actually confuses me is the weights. If "0" is very thin on startup, wouldn't thicker (forgive the term., guess it should be "heavier'), be better for a cold engine. I guess the downside on that is some will say it takes longer to get to the parts. I know the LS1 is known for engine slap. So what, if any, would be a good oil for that. I know nothing will cure it but something should help it. I can't believe GM would throw an engine like that in a Corvette & call it a true high perf. car. Yea I know, some will say it won't hurt anything, it sure as hell won't help either. Anyway thanks so much for the info.

tracer1

 

I work part time for Advance Auto Parts, and was just looking at a bottle of the new "house brand" syn oil today....it meets the GM spec. In all honesty, I was a little surprised, considering it sells for $3-4/qt less than the "brand name" oils.

 

Not quite sure what you mean by the above statement, so a short explanation.

All fluids lose viscosity as they heat up. A typical 5w30 has a viscosity of about 60 cSt at 100F and about 10 cSt at 212F, a drop of about six!

Before multi-grade oils, most oils were straight grade, e.g. SAE 30. Straight weight oils behave like 30 grade oils hot and cold and cannot have viscosity improvers. A straight 30 grade oil has a much higher viscosity when hot and cold than does a lower grade oil (like SAE 5w). If you plotted viscosity vs. temperature for a straight 30 grade oil, the plot would have a steep negative slope, and would be higher than the similarly shapped curve for an SAE 5w.

Multi-grade oils behave like lower viscosity fluids when cold, but hold their viscosity better as they heat up (drops less) and behave like higher viscosity fluids when hot. A multi-grade 5w30 has the viscosity of a straight SAE 5w when cold, but retains enough viscosity as it heats up to have the viscosity of a 30 grade when hot. But it still loses a lot of viscosity as it heats up - just less than a straight SAE 5w would. The slope of the above mentioned curve would be flatter - but not flat.

Prior to synthetics, to get conventional oil to retain viscosity, the oil needed viscosity improvers. These VIs have the property that in cold temperatures their polymers coil up, contributing little to the base oils viscosity measurements. At higher temperatures they uncoil to reduce the base oils loss of viscosity as it heats up. Their problem is that when the VIs break down (shear down) one is left with properties of the original base oil (the 5w). Thus over time, a low quality 5w30 could over time shear down to a 5w20, or worse.

Good synthetics basestocks are naturally multi-viscosity as their basestock does not lose viscosity as fast as conventional oil as they heat up. Thus many top synthetics can acheive a 10w30 rating with no viscosity improvers, thus are very shear resistant.

To turn a 10w30 synthetic into a 0w30 synthetic would almost certainly require viscosity improvers.

To put some numbers on the above, a 30 grade oil is defined by having a kinematic viscosity of 9.30-12.49 cSt at 100C (212F). In addition, each viscosity classification has High Temp High Shear (HTHS) rating requirements as measured at 150C (~300F). 30 grade oils must have a minimum HTHS viscosity of 2.9 cSt. Interesting to note that that band has about a 30% spread - not all 30 grades are the same!

Cold viscosity is measured by Brookfield viscosity (cP). A 5w must have a Brookfield viscosity of less than 6600 cP at -30C and also must have a Brookfield pumping viscosity of less than 60,000 cP at -35C (-31F). For comparison, a 0w must have a Brookfield viscosity of less than 6200 cP at -35C and also must have a Brookfield pumping viscosity of less than 60,000 cP at -40C (-31F).

So, when the oil is "cold" a 0w generally means the oil will flow better providing better lubrication to those parts of the engine that need it, but do not take away that a 0w is "thin" when cold - its viscosity is many many times higher than a 30 grade's viscosity when "hot".

Given the above variances, not all 0w30 or 5w30 are the same - the blender has a fairly wide band in which to blend the oil depending on the intended use. For example, the racing 10w30 I use sits very high in the 30 grade viscosity band. Most 0w30s are aimed at improved fuel economy, thus sit low in the band (less fluid friction).

Some examples :
Mobil 1 0w30
- Pour point - 50C
- 100F 62.9 cSt
- 212F 10.9 cSt
- HTHS 3.0 cSt
Mobil 1 5w30
- Pour point - 42C
- 100F 61.7 cSt
- 212F 11.0 cSt
- HTHS 3.1 cSt
AMSOIL 0w30
- Pour point - 51C
- 100F 59.0 cSt
- 212F 10.5 cSt
- HTHS 3.1 cSt
AMSOIL 5w30
- Pour point - 51C
- 100F 60.3 cSt
- 212F 10.5 cSt
- HTHS 3.2 cSt
AMSOIL 10w30 (Dominator Racing Oil)
- Pour point - 42C
- 100F 69.0 cSt
- 212F 11.5 cSt
- HTHS 3.6 cSt

As you can see from the above, it is hard to draw blanket conclusions. For example, the AMSOIL 5w30 has a lower viscosity at 100F (flows better) than does the M1 0w30, also has a (slightly) lower pour point of -51C vs. -50C, but provides better high temp high shear protection (3.2 vs. 3.0). Without really going to the oil's product data sheet (and not all companies share the above info like AMSOIL and M1 do) to determine whether a specific brand's oil flows better cold or performs better hot just by the viscosity grade. Too complicated for the high level view to be completely accurate.

 

Not (generally) sold over the counter alternatives if you are interested:
AMSOIL Synthetic 5w40 European Motor Oil
AMSOIL Synthetic 5w30 European Motor Oil

 

Ya, I talked to my brother (Masters in petro-chem eng.) who works with an Engineer who worked in a sausage factory, he says the same thing, I guess making sausage gives him insiders knowledge.HILAROUS,no fact based opinions just well, opinions, which are like a$$holes, because everyones got one!

 

......evidently not.......

http://life.globaltimes.cn/odd/2011-02/628018.html

 

 

Thanks I was aware of this product but prefer over the shelf so if I ever need oil it is in most parts houses.

For the question thick oil better on cold start up. No. you want very thin so it will flow very quickly and lubricate. You need low viscosity and high film strength to protect on the cold start up. Conventional oil at very cold temps can jell and not flow resulting in engine burn out / failrue. This has happened many times in cold climates with thick conventional oils.

Note many aircraft (Fly Alaska) will show how they warm the engines so the 50+ W aircraft oil will flow on start up and not damage the aircraft engine.

 

I think I've known some people that may have had two.

tracer1

 

Will probably go with M1 0w-40 euro. It's available locally and $8.79 qt. Would get the 5 gal container if avalable. Would like to run Amsoil, Redline, or Rpyal Purple but it's not readily available on the shelf
Oh, one other dumb question: Why is racing oil not recommended for street vehicles?

tracer1

 

Racing oils do not have the detergents and dispersants needed for street oil change intervals. I use a racing 10w30, but change my oil at about 500 mile intervals.

 

What is wrong with following GM recomendation and just use Mobile 1 I have seen hundreds of vetts that used nothing but and have never heard a complaint that the oil caused anything negative.

 

 

Lucky I believe that you had the right idea on your first post.

 

Yea, I agree......looks like several of those (opinions) just walked in.

Thanks for all the intelligent input from Subdriver & others.

Moderator you may close this thread since it offends others.

tracer1

 

Well I guess out of umpteenbillion in China, there bound to be one A -holess, opinionated perrson?!