Sponsors Engine Oil Viscosity

Discussion in 'Opieoils' started by oilman, Tuesday 17th Sep, 2013.

  1. oilman Special Partner Club Affiliate

    Engine Oil Viscosity

    Viscosity is the most misunderstood aspect of oil and yet it is the most important.

    Viscosity is the force required to shear (break) the oil at a certain speed and temperature. Oils work because they have viscosity; the drag of a rotating part pulls oil from a low-pressure area into a high pressure area and “floats” the surfaces apart. This is called “hydrodynamic lubrication” and crankbearings depend on it.

    Oil must be capable of flowing at low temperatures, so that it gets around the engine in a fraction of a second at start-up and must protect engine components at high temperatures without evaporating or carbonising and maintain adequate (not excessive) oil pressure. Many people think that the thicker the oil, the better the protection, but if the oil is too thick, it will not flow properly, leading to reduced protection.

    The numbers on every can of oil indicate its performance characteristics when new but there are many misconceptions on what these numbers actually mean.

    For multigrade oils you will see two numbers (for monograde oils only one). The first is followed by a “w” and is commonly 0, 5, 10, 15 or 20. The second number is always higher than the first and is commonly 20, 30, 40, 50 or 60. The first and second numbers ARE NOT related.

    The “w” number (0, 5, 10, 15 or 20)
    When multigrade oils first appeared, a low temperature test called “w” (meaning “winter” not weight) was introduced. Using a “Cold Crank Simulator", the test measures the oils ability to flow at low temperatures. ALL oils are THICKER at low temperatures than at high temperatures but the lower the “w” number, the quicker the oil will flow at low temperatures.

    The second number (20, 30, 40, 50 or 60)
    This number is known as the SAE (Society of Automotive Engineers) number and is measured in “Centistokes” (cst) at 100C. Centistokes (cst) is the measure of a fluid's resistance to flow (viscosity). It is calculated in terms of the time required for a standard quantity of fluid at a certain temperature to flow through a standard orifice. The higher the value, the thicker the oil.

    An oils cst at 100C determines its SAE rating within the following parameters.
    SAE 20 = 5.6 to less than 9.3cst
    SAE 30 = 9.3 to less than 12.5cst
    SAE 40 = 12.5 to less than 16.3cst
    SAE 50 = 16.3 to less than 21.9cst
    SAE 60 = 21.9 to less than 26.0cst

    ALL oils labelled 40 must fall within the SAE parameters at 100C so everything from a monograde 40 to multigrade 0w-40, 5w-40, 10w-40, 15w-40 or 20w-40 are approximately the same thickness at 100C.

    Some oil companies label oils as SAE 35, 45 or 55, but as you can see from the above figures, there isn't a SAE 35, 45 or 55. This "could" be because they are approximately on the boundary of the two grades, but as we don't deal with any of those I can't really comment further.

    Summary

    Cold start.
    A 5w-40 will flow better than a 10w-40.
    A 10w-50 will flow better than a 15w-50
    A 5w-40 is the same as a 5w-30

    At operating temperatures.
    A 10w-50 is thicker than a 10w-40.
    A 15w-50 is thicker than a 5w-40
    A 0w-40 is the same as a 10w-40

    If you look above, you will see that the figures quoted do not indicate at all as to whether the oil is synthetic or mineral based... Well except for 0w oils as synthetic PAO basestock is required to acheive this viscosity.

    Generally the oil you use should be based on the manufacturers recommendation found in the owners manual, but then modifications, climate and the type of use can affect that recommendation. If you are unsure of what is the correct recommendation for your car and would like to know more please contact us here oilman@opieoils.co.uk

    With thanks to John Rowland of Fuchs/Silkolene

    Cheers

    Tim and the Opie Oils team
     
    AccordCU2 likes this.
  2. Ichiban Founder Staff Team

    England CJ Leeds
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    I wish Penelope pit stop or bee on the oil bonnet was still on this forum .. Would have highlighted a few extracts out of the above ..LOL

    Thanks Opie
     
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  3. AccordCU2 Expert Advisor ★ ★ ★ ★ ★

    I know this has been done to death but have to ask your expert opinion.
    I have 8th Generation 2.4 manual Accord.What oil would you use if it was your own car?.
    I currently use Fuchs titan pro s 5w-40 courtesy of your good offer, that reminds me need to order some more.
    Thanks
     
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  4. ArcticFire-Account Closed Banned Getting Started

    Scotland Graham Scotland
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    Nice info. I'm about to order some 0w20 from you to replace the 0w30 castrol currently in. Would you recommended an engine flush to clear out the old stuff seeing as I'm changing grades?
     
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  5. Primarycare Expert Advisor ★ ★ ★ ★ ★

    United Kingdom Primary c Northampton
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    Brilliant info best and clearest breakdown of the myth surrounding oil I have read

    Nice one
     
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  6. oilman Special Partner Club Affiliate


    The Pro S 5w-40 is ideal, if you like to drive it hard. The 5w-30 version would be a better choice for standard use.

    Cheers

    Tim

    - - - Updated - - -

    Sure you want to go for 0w-20? It's very thin, so can lead to high oil consumption and potentially less protection. No need for a flush, they can do more harm than good. You're better off just getting the oil warm so it all flows out easily.

    Cheers

    Tim
     
    AccordCU2 likes this.
  7. AccordCU2 Expert Advisor ★ ★ ★ ★ ★

    Thanks Tim
    I will stick with 5w-40 as I do have heavy right foot.
     
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  8. ArcticFire-Account Closed Banned Getting Started

    Scotland Graham Scotland
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    I'm sure I read that CJ here uses 0W20 and it doesn't use a drop? The manual also recommends this as the oil to use and say 0W30 is ok if you can't get 0W20 so I figured I may as well go for it! lol Isn't it better for economy?

    Also, I thought the numbers were mainly about flow and it's the actual quality of the oil itself which determines its protection levels? Can't remember the term, something like the film tear point or breaking point but basically you could get two 0W30 oils with one being crap and the other offering better protection than even thicker oils etc?
     
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  9. Ichiban Founder Staff Team

    England CJ Leeds
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    Yup using the Honda oil 0w-20 I have done 3 oil changes at 4K miles and even on repeated canning there is no sign of oil burn at all . Great power and top off great fuel effeincy ..
     
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  10. ArcticFire-Account Closed Banned Getting Started

    Scotland Graham Scotland
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    I've just sourced Mobil 1 0W20 for £9.90 per litre (comes in a pack of twelve 1 litre bottles) but if ordering 100 litres or more then it will be £7.40 per litre. Would this be a good buy?
     
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  11. Ichiban Founder Staff Team

    England CJ Leeds
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    Graham I would suggest you stick with 0w-30 and upwards on your car which has been run on thicker oils. I made the switch using 0w-20 on my 7th Generation after great results on the 8th Generation.

    However my 7th Generation has been run on 5w-40 Silkolene all it life , the minute I changed the oil to 0w-20 on the the 7th Generation the car ran like a dog it didn't like the oil, the engine felt strange and felt very vague. The power and fuel efficiency went straight up but going through the gears and half throttle bursts did not feel right not fluid as it used to be.

    Changed back to Pro -s 5w-40 and it was smooth fluid and punchy even in repeated canning..

    That why I am going to stick with 0w-20 on a brand new engine. Hope this helps.
     
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  12. Ichiban Founder Staff Team

    England CJ Leeds
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    Graham have a look at this thread bud this is what I have achived on a full tank on my 7th Generation running 5w-40 http://hondakarma.com/threads/7478/

    Its a good oil and clearly fuel efficient.
     
    Last edited by a moderator: Sunday 23rd Feb, 2014
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  13. ArcticFire-Account Closed Banned Getting Started

    Scotland Graham Scotland
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    The manual says 0W20 though?
     
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  14. Ichiban Founder Staff Team

    England CJ Leeds
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    yes mate you are right the manual mention and so does Honda advocate its use . it will run fine but I have given you some pointers so you can make an informed decision fella just in case you find your car feeling vague.
     
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  15. ArcticFire-Account Closed Banned Getting Started

    Scotland Graham Scotland
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    Cool cheers. I'll have a think.
     
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  16. i-DSI Expert Advisor ★ ★ ★ ★ ★

    Belgium Aalst
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    Hi Arcticfire,
    Want to share my experience with 0W20 also.
    Me to, I'm using 0W20 in our 2 current Honda's:
    - Accord 2.0 i-VTEC 2011 from new on fed with 0W20 => always long drivecycles, doesn't use a single drop of oil. Drive at very low revs, extremely high MPG (for petrol), and redline the engine from time to time, only when warm.
    - Civic 1.4 I-DSI 2008, started at previous owner with 5W30 (Total or Elf), switched to 0W2 once in our hands. 80% very short drivecycles, never redline and doesn't use any oil.
    - Civic 1.4 I-DSI 2007 (my previous car, sold 1 year ago): usage same as Accord, but had 10W40 (!) before I switched to 0W20. Didn't consume a drop of oil.
    All 3 cars never felt strange, high to very high MPG and engines still run as new. Accord is at 55k miles, Civic 30k. All cars were bought 2nd hand.
     
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  17. ArcticFire-Account Closed Banned Getting Started

    Scotland Graham Scotland
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    Cheers. I'm feeling the performance of my car has deteriorated recently and I'm wondering if it's the Castrol no longer doing its job properly? What I'm also thinking is that if I can get this stuff so cheap then why not give it a bash? lol
     
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  18. i-DSI Expert Advisor ★ ★ ★ ★ ★

    Belgium Aalst
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    Performance down?
    I'd look first for other reasons than the simple fact of using Castrol 0W30 which should be a pretty decent oil. How long is the oil in it? How many miles?
    Spark plugs, valve clearance, air filter, ...? Very important for performance.
    0W20 will give you a performance advantage, but compared to 0W30 it can't be that much.
     
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  19. AccordCU2 Expert Advisor ★ ★ ★ ★ ★

    Hi Tim
    Few questions about this oil if I may.Fuchs Titan 0w 20
    How good is it? Is it available to buy in UK? If so what's the price?
     

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  20. Eck Senior Member ★ ★ ☆ ☆ ☆

    Maybe some attention should be paid to the ACEA category specified by Honda, since all that seems to be talked about is viscosity and sometimes engine characteristic changes after oil change. Maybe some attention should be paid to this other aspect of an oils specification before choosing it for use in a Honda engine.
    Maybe Opie could make some comment on the importance or otherwise of this? Did ask before but can't find my comment, probably in another forum.