Synthetic Blend vs Full Synthetic Pro and Cons

Discussion in 'General' started by Justin23, Aug 5, 2017.

  1. RedylC94

    RedylC94 Well-Known Member

    My memory says Mobil1 was $4 when it first appeared in the US, back when respectable regular oil was typically 79¢ or so on sale. But that original 5W-20 Mobil1 was made of more exotic stuff than today's typical "synthetics."
     
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  2. Justin23

    Justin23 Member

    I just read about how Chrysler recommends Pennzoil for their vehicles claiming it helps improve fuel economy even with conventional. How is that ?
     
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  3. phoebeisis

    phoebeisis Well-Known Member


    and -pretty early maybe 1978- "someone" developed the synthetic oil with graphite in it-??
    That graphite suspended in it oil-probably started the synthetic oils leak past gaskets tale
    Now it was true-the synthetic base was EXTREMELY thin-and it did leak past mid 1970's gaskets-
    so bottoms of engines valve covers-entire engine bays on the low QC cars of that day-
    were smeared with filthy(forget gettin git out of clothing) sooty black gunk
    Maybe it was ARCO GRAFTEC ??? No idea who ARCO was or is

    But you-REDY are right-regular oil was dirt cheap-under $1-and if you were really cheap-and had a car that leaked or used oil
    You could buy RECYCLED oil -in qt cans-for 25 cents or so!!
    Guessing recycled oil was just filtered-water boiled off-and that was that-they probably did something to remove oxidized oil-maybe just cool it-and it would harden-scoop it off

    Gee I would bet these synthetics-probably still pretty good oil at 15000 miles-but no one re-uses oil as oil-too bad
     
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  4. RedylC94

    RedylC94 Well-Known Member

    ARCO= former Atlantic Richfield Co. No, ArcoGraphite oil was not synthetic, and it met the same viscosity standards as other oils of the same viscosity designation, therefore didn't leak more than other oils. However, because of its inky appearance it was more visible when it did. They claimed tests proved the colloidal graphite additive reduced friction. I used 3 or 4 cases (72 or 96 quarts) of the stuff in my Mazda in its youth. I had no problems at all with it. Unlike some other brands back then , it didn't become sludge in the Mazda.
     
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  5. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Justin, only if its kinematic viscosity is lower than the same weight of something else. Strange claim however???

    Wayne
     
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  6. Justin23

    Justin23 Member

    Wayne , could you explain kinematic viscosity ? I have no idea what it means.
     
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  7. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Justin:

    It is one of the simplest oil tests.

    From the SAE paper on the ASTM D445 test standard describing the method:

    This test method specifies a procedure for the determination of the kinematic viscosity, ν, of liquid petroleum products, both transparent and opaque, by measuring the time for a volume of liquid to flow under gravity through a calibrated glass capillary viscometer. The dynamic viscosity, η, can be obtained by multiplying the kinematic viscosity, ν, by the density, ρ, of the liquid.

    For crankcase oils, it is measured by 1 mm2/s = 10-6 m2/s = 1 cSat at both 40 degrees C and 100 degrees C. The 100 degrees C is a operating temperature for oil which is why it is so important.

    Moving to the Pour Point, at what temperature can it still be poured. Synthetics of a given weight are usually able to pour at lower temperatures than similar weight non-synthetics. I am not sure if that is a product of the designed chains or modifiers that are incorporated. Either way, if you want to start your car up at -25 degrees F, the lowest weight oil recommended for your car with the lowest kinematic viscosity and lowest pour point is what you want.

    Wayne
     
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  8. Justin23

    Justin23 Member

    That makes sense now. And what about HTHS in oil ? As in how does it affect a engine ?
     
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  9. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Justin:

    HTHS is a test completed at 150 degrees C by a tapered bearing at a shear rate of 10E06/sec or viscometer at 1.4E06/sec and relates to oil film thickness in high shear areas of an engine. You want that film thickness to be enough so moving metal does not touch moving metal at that temperature.

    Wayne
     
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  10. Justin23

    Justin23 Member

    So is that why my vehicle prefers a 10w30 over a 5w30 ?
     
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  11. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Justin:

    It may have been designed for 10W-30? What does your manual say?

    Wayne
     
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  12. RedylC94

    RedylC94 Well-Known Member

    That acronym stands for high temperature, high shear rate viscosity, measured under the conditions Wayne noted. It turns out to be a lot more significant that the conventionally reported 100°C, low-shear-rate viscosity in predicting whether the hydrodynamic film will be maintained in bearings.
     
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  13. RedylC94

    RedylC94 Well-Known Member

    The difference between those grades, by definition, has to do only with the lowest temperature at which they can be pumped, and the lowest temperature at which they don't create excessive drag in bearings. (Those two tests replace the obsolecent pour point specification, which doesn't correlate with cold-start problems in real engines as well.)

    Because the "-30" part of those two grades is the same, they meet the same requirements at high temperatures and should perform identically when hot---at least in theory.
     
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  14. Justin23

    Justin23 Member

    10w30 or 5w30. 10w30 preferred. It doesn't recommend 5w30 until freezing temps. But the owners manual was written 28 years ago.
     
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  15. phoebeisis

    phoebeisis Well-Known Member

    Redy-memory tricky-thanks
    A buddy of mine put it in his motorcycle- a XS500 -2 cylinder Yamaha-it made all the joints look fithy sooty-got all over his clothing
     
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  16. alster

    alster Well-Known Member

    I believe if you vehicle calls for 10W30 oil or 5W30 oil you can also use 0W30 synthetic oil as well. Perhaps you will obtain
    a little more mpg's, and easier starting in cold weather.
     
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  17. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    Charlie , I rode the motorcycle you mentioned. But my memory says (1973) that it was called a TX500. My memory might be defective. It was an eight-valve twin , which was a great engine. And the bike was VERY tall, a fact that both you and I would remember well. My dad , who was 5'5" , put a lowering kit on it. Are we talking about the same motorcycle ?
     
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  18. RedylC94

    RedylC94 Well-Known Member

    That's the key. 28 years ago 5W-30s were not as shear-stable as modern ones, so manufacturers back then were more concerned that it would eventually thin out too much---and not as concerned about warm-up fuel consumption.
     
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  19. Justin23

    Justin23 Member

    From what the manual says the 10w30 is preferred because of film strength and startup wear.
     
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  20. 08EscapeHybrid

    08EscapeHybrid Moderator

    I have said this many times...
     
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