Calling oil/gas expert Tom.....

Mopar Boy

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Few questions for you Tom!

1 - Oil. If oil was left in the shed, stayed in -40F over the winter, is it still good to use? What about oil that was stored in the shed at 100F + over a summer? (See where this is going? Found a case of oil in the shed.....;))

2 - Fuel. So I am told that I should not use Sunoca 94 in the Viper. Doesn't need that high of octane. So looking around my area, I have a choice of 94 or the next step down is 91 with "up to 10 % ethanol". Am I still better with the 91 or the non ethanol 94?

Thank you sir!:hail:

Robert
 

Tom F&L GoR

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Few questions for you Tom!

1 - Oil. If oil was left in the shed, stayed in -40F over the winter, is it still good to use? What about oil that was stored in the shed at 100F + over a summer? (See where this is going? Found a case of oil in the shed.....;))

2 - Fuel. So I am told that I should not use Sunoca 94 in the Viper. Doesn't need that high of octane. So looking around my area, I have a choice of 94 or the next step down is 91 with "up to 10 % ethanol". Am I still better with the 91 or the non ethanol 94?

Thank you sir!:hail:

Robert

Hi Robert.
Ans 1: -40F is no problem and actually good since it will slow any degradation. 100F is not bad, assuming the cap is on tight and better yet, never opened. Open bottles would breathe every day as the air warmed and cooled. And if it's only one year old, no problem in using it.
Ans 2: You can use Sunoco 94, it is simply that the engine can't appreciate the higher octane. It is frankly a waste of your money, too. The 91 octane with ethanol will be fine; the engine was designed to run with it so there is no debit. In the US it is quite common and the odd benefit is that it is usually the "premium" grade so that fuel marketers put more detergent additive in this grade. It is worth it for the cleanliness.

You probably save $3-$4 per tank with the 91? Consider driving in a manner to turn that into extra smiles!
 

Tom F&L GoR

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Dave, an engineer's explanation: marketing allows two (or more) "best" entities. Both can be tops at their game. However, advertisers get really upset if one entity is labeled "better" because that is a true superiority claim. Such a comparitive is unambiguous; one entity stands as more desirable than the other. Consequently the logical order of preference is good-best-better.

So, do you really want to be the "best"? :dunno:
 

GTSnake

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And I thought oil was already thousands of years old. How could it have a shelf life? :dunno:

Cooking oil I can understand since it's organic but petroleum is not so how would it ever expire?
 

dave6666

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Explaining Viper things to you
And I thought oil was already thousands of years old. How could it have a shelf life? :dunno:

Cooking oil I can understand since it's organic but petroleum is not so how would it ever expire?

Oil is thousands of years old before it's refined and the additives are added. Then it's circa last Tuesday.

And by the definition of organic meaning carbon based, why is a hydrocarbon product not organic?

What is Organic Chemistry?
 

Tom F&L GoR

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Crude oil, yes. Refined oil used for engine oil takes things out and puts stuff in. The resulting formulation has detergents, dispersants, antiwear additives, anti-oxidants, friction modifiers, etc to provide benefits to the engine. These chemicals become active under conditions dictated by the heat and pressure the oil experiences... but what it really means is that they become active much, much more quickly under the conditions in an engine and become active (or used up) much more slowly while sitting on the shelf. So eventually these vitamins have an expiration date and what you see happen to cooking oil in a few days or weeks actually happens to engine oil in years and perhaps decades.
 

GTSnake

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So the oil is still good just the additives expire? Then there's really no reason not to use old oil for it's basic lubricating properties right?
 

Billy Coons

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Crude oil, yes. Refined oil used for engine oil takes things out and puts stuff in. The resulting formulation has detergents, dispersants, antiwear additives, anti-oxidants, friction modifiers, etc to provide benefits to the engine. These chemicals become active under conditions dictated by the heat and pressure the oil experiences... but what it really means is that they become active much, much more quickly under the conditions in an engine and become active (or used up) much more slowly while sitting on the shelf. So eventually these vitamins have an expiration date and what you see happen to cooking oil in a few days or weeks actually happens to engine oil in years and perhaps decades.

Hmmmm... so now I may just have to break open & use that unopened 10-yr old case of Mobil 1 syn 5w-30 I've been keeping in my shed year round! :headbang: Think I may also have an unopened bottle of Dura-Lube & Slick 50 in there from the same time!
 

Tom F&L GoR

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So the oil is still good just the additives expire? Then there's really no reason not to use old oil for it's basic lubricating properties right?

No, the oil will deteriorate also. Slowly over time, but it will. I think the oil companies will officially say you can use oil after 3-5 years but after that amount of time the new version of oil has come out and they'll tell you to buy the better stuff.

If you want to use it for your lawnmower or hinges, fine. But an automotive engine needs lubrication, anti-wear protection, cleaning, protection from the exhaust blowby that causes acid build up and sludge, protection from dust in the air, and effects of heat, cold, changing from cold to hot suddenly.... etc.
 

Tom F&L GoR

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So why not add in an anti-aging compound?

There are anti-oxidants, but many of these additives are sacrificial. They "die" first so the bulk oil is left in good shape. When these front line soldiers are all dead, the bulk oil is next.

Geez, guys, how long do you want unopened oil to last?
 

mnviper

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Tom, Since this is a "live" oil thread I couldn't resist a general oil theory question:
I've learned quite a bit from reading your previous responses on oil threads and I've noticed that you put a lot of stock in the additive package of the oil, while on the other hand the marketing for oils like RedLine and Motul push the fact that they use a Group V ester base that reduces the amount of necessary additives which they claim may "sheer" under certain conditions. Is this a legitimate argument for the extra expense of a group V oil?
 
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Mopar Boy

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Well, as we are all asking questions, I have another. Any need to add aftermarket zinc or other additives to the oil? Just asking as the zinc count was diminished with the new oil standards.....

Thanks!
 

Tom F&L GoR

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Tom, Since this is a "live" oil thread I couldn't resist a general oil theory question:
I've learned quite a bit from reading your previous responses on oil threads and I've noticed that you put a lot of stock in the additive package of the oil, while on the other hand the marketing for oils like RedLine and Motul push the fact that they use a Group V ester base that reduces the amount of necessary additives which they claim may "sheer" under certain conditions. Is this a legitimate argument for the extra expense of a group V oil?

One type of additive is a very large molecular weight component designed to provide the multigrade viscosity performance. These large molecules shrink in the cold, so they do not interfere as much with flow, and let cold oil behave "thin" and runny. At higher temperatures they expand, unfurl, and generally get in the way, so the oil behaves "thicker". These additives are viscosity modifiers or viscosity index improvers.

Because they are physically large, they can stretch or break. However, if one large spaghetti piece is cut in half, the thickening power of the two smaller pieces is not the same as the one long piece. Some VMs are more robust than others and resist this shear. Some formulations just put more smaller VMs in the oil so it shears less in service. Other VMs are designed differently, such as a star-fish shape rather than a long spaghetti. The star polymer can still provide thickening because the diameter is large, but the length in any one direction is not. So it is more shear-stable and less likely to shear.

People may argue that high speeds and high loads and high temperatures shear an oil more. I will remind you that a particular viscosity grade (pick SAE 30) is actually a range of 9.3 centiStokes to 12.5 cSt. So if the oil started at 12 cSt and shears to 11 cSt it is still an SAE 30. I would then argue that since the oil stayed in grade, the engine won't really know or care. These ranges were, after all, chosen for that reason - that within the range, an engine performed the same.

Higher "performance" base oils like synthetics have a naturally higher viscosity index. That means to make a 10W40 with cheap mineral oil you may need to add 10% VM, but to make a 10W40 synthetic you may only need 6%. In service the synthetic will shear less because there is less VM to shear! Esters are directionally better than PAO or Group III base oils, so I will give the benefit of the doubt to Motul and the ester blends that they shear the least.

The amount of VM in an oil is not exactly intuitive. A 10W30, 15W40, or 20W50 would not have as much as a 5W30 or 10W40. Synthetics will always have less than an equivalent mineral oil version.

With the science behind us I still would not base a purchase decision on shear. All API certified oils have test requirements to stay in grade. Any type of synthetic oil has less VM to start with, so will shear less. Your engine can't tell the difference of a 1 cSt change in viscosity. Performance oils would use a more shear stable VM anyway. Have you ever heard of an engine failure due to shear? (I haven't.)

Esters have a high natural viscosity index, high temperature capability, are polar and stick to metal surfaces, and some other technical benefits. These are more realistic performance enhancements than claiming better resistance to shear.
 

Tom F&L GoR

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I'm still working on the Stay Fresh Beer Bottle. My target is good head even after twisting that top one month ago. I hope to get something going on the perfect oil can later this Fall.

Dave, I'll send you my beer carbonator. Lets you fizz then whizz. Let me know when you're ready for the oil freshener.
 

Tom F&L GoR

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Well, as we are all asking questions, I have another. Any need to add aftermarket zinc or other additives to the oil? Just asking as the zinc count was diminished with the new oil standards.....

Thanks!

Not yet. To get reasonable zinc (the important component is really phosphorus) levels you still have a choice of:

  • mineral diesel oil (only 15W40)
  • synthetic diesel oil (only in 5W40)
  • Euro formulations like Mobil 0W40 (i.e. anything thicker than xxW30 is above the viscosity that the US OEMs care about)
  • motorcycle oils that are rated API SG (many viscosity grades)
  • Joe Gibbs Hot Rod oil, and surely there will be others soon.
While I do not see a health hazard, safety issue, or mishandling problem with ZDDP as a store-bought additive, I have not seen a marketer do it yet. Maybe I should....
 

Tom F&L GoR

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Tom,
Thanks for the explanation. So would a higher HTHS number within a grade of similar base stock oils indicate that more robust VMs are being used?

Also, regarding the previous question on ZDDP content, I found this page to be useful for comparing Mobil 1 oils: http://www.mobiloil.com/USA-English/MotorOil/Files/Mobil_1_Product_Guide.pdf

That is actually an insider question - you know more than you are letting on.

No, HTHS is mostly determined by the base oil viscosity. HTHS is high temperature, high shear viscosity and under these conditions the VM doesn't matter as much - they are all stretched and not contributing much. So a higher HTHS within a grade means the formulation used a higher viscosity index base oil since it is "thicker" at high temps yet still thin enough to meet a low W grade number.

Thanks for the summary, that is convenient. Unfortunately the rules get complicated, but remember this thought - The US OEMs only care about xxW-30 and lower for their fuel economy and emissions needs. Therefore xxW-40 and higher can still have higher (i.e. reasonable) levels of ZDDP. The table shows that Mobil (and other brands ) oils with Euro specs are still higher ZDDP.

Motorcycle oils on the table are OK for engine use. The racing oils - have to look into the rest of the additive package. Often then do not have the full amount of detergents, dispersants, and other additives for a normal oil drain length. Like those diesel oils, though.
 

Tom F&L GoR

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The argument VM suppliers make for their products is providing a higher viscosity or less shear, but the numbers they use are kinematic viscosity at 100C. HTHS is a much higher shear rate (10^6) than letting the oil flow via gravity through a tube (kinematic measurement) and at higher temperature (150C vs. 100C)

Thinking about the original question more, if you closely specify the kin vis at 100C (rather than the grade range) among similar base oils, and then compare HTHS you might see some difference. And I also would modify "robust" since I took that as a description of the additive itself. There are differences in shear stability of the additive, but a formulation can have higher shear stability by using a larger treat rate of a lower molecular weight VM. In other words, formulation A with 10% VM might be more shear stable than formulation B at 10%. However, by adjusting the base oil viscosity you could use 12% of another VM to get the same multigrade with higher shear stability. You could still have similar HTHS, kin vis at 100C, etc.

Perhaps what I am getting to is that the difference might only be shown with a well-organized formulation exercise.

I worked on an engine test (gulp) in the mid 80's called the Bearing Oil Film Thickness (BOFT) test. It used an electrically isolated main bearing and charged it like a capacitor. Make a few assumptions and a few calculations later you predict a distance between the crank and the bearing. This engine and the data generated helped understand the effect of base oil, VM, VM type, and was the data set used to create the HTHS specifications that are now part of the viscosity grade category.

In the future it makes sense to drop the use of kinematic viscosity; it was a measurement that correlated fairly well when lubricants were developed. But HTHS is a better bearing viscosity estimate and is used to predict fuel economy more accurately.
 
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