What Was the Point of 20W20

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I remember in the 80s when Kendall marketed a version of my other favorite green oil, GT-1, that was 20W20. What was the point (IOW how much difference could there have been between the 20W and the 20)? [ August 13, 2003, 06:57 PM: Message edited by: pscholte ]
 
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It was aound in 1972, because the owner's manual is still in the glove box of our 1972 Ford C750 fire truck. Ford recommended 20w20 for winter and either 30 or 40 straight for warm weather. I'll take my SL 3w30 thank you! I guess the good old days were'nt always so good!
 

pscholte

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quote:
Originally posted by timzak: Pennzoil still has a 20W-20 data sheet on their website.
timzak, Went to the website and looked at the tech data...other than the fact that 20W20 has a borderline pumping temp published and the 30wt and above don't, I didn't see anything that jumps out and says, Here's why."
 
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The "20W" part shows that it passed a cold viscosity test, and it also passes the "20" wt. hot viscosity test. A straight 20 wt. oil does not have to be tested cold, so it might be much thicker when cold. Ken
 
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Most oil companies market an SAE 20 or 20W20 HDMO CF2, CF/SJ. Here is one example from Petro-Cannuck sold as an SAE 20: API CF/SJ flash 231C/448F VI 118 [email protected] [email protected] HTHS 2.7 -20C 4932 cSt pour point -39C Ash 1.0 TBN 7.9 Fron the specs it might be a 10W20, but not sold as such. price $1.70 US$/US qt or $2.50 CND$/litre The personl problem with the newq 5W20s is not the SAE 20 part, but the high evaporative losses and low flash points, inviting oil consumption and change of grade over the lubricants' service life. Maybe I'll try some just for fun in testing.
 

pscholte

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userfriendly, Thanks for the detailed info. I was wondering why the oil companies didn't at least go for a 10W20 vice a 20W20. It just doesn't seem to have a real point to me. I would think that even 30 years ago they could have produced a stable 10W20 if there was a need for an oil in that range. [ August 13, 2003, 10:40 PM: Message edited by: pscholte ]
 
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GM was big on 20W20!! It was for gas millage!! Lots of black death from Adam Opels runing 20W20!!! 20W baaaad! 5W20 even worse!!!!!
 

Jay

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I think what has happened is that basestock refining technology has improved over the years to the point that it's ridiculously easy to meet 10w-20, but people's perception (and understanding of the "w" designation) has not kept pace. So oilmakers call their 10w-20 oils 20w-20 because that's what the manual says to get. We see the same thing happening today with 5w-20 and 0w-20. [ August 14, 2003, 12:07 AM: Message edited by: Jay ]
 
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quote:
Originally posted by Ken2: The "20W" part shows that it passed a cold viscosity test, and it also passes the "20" wt. hot viscosity test. A straight 20 wt. oil does not have to be tested cold, so it might be much thicker when cold.
My head's still spinning. [freaknout] How hard can it be for any 20 weight base stock to behave like a cold 20 weight oil when it's cold? [ August 14, 2003, 06:36 PM: Message edited by: Ray H ]
 

pscholte

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quote:
Originally posted by Ray H: My head's still spinning. [freaknout] How hard can it be for any 20 weight base stock to behave like a cold 20 weight oil when it's cold?
Ray, I think you are thinking what I've been thinking, what'd'ya think?
 
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quote:
Originally posted by pscholte: I think you are thinking what I've been thinking, what'd'ya think?
I'll get back to you later when I can think. (I think...)
 

mph

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quote:
Originally posted by Ray H: How hard can it be for any 20 weight base stock to behave like a cold 20 weight oil when it's cold?
You're operating under the common, but mistaken, belief that "20W" means "acts like a 20 weight when cold." The two numbers don't have anything to do with each other. There's a list of cold viscosities that are necessary for 0W, 5W, 10W, 15W, 20W, and a list of hot viscosities for 20, 30, 40, 50, etc., but there's not really anything tying those lists together. That the numbers suggest a relationship is unfortunate.
 
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Many years back my step-father carpooled with a guy who ran Montgomery Wards 20W-20 in all his vehicles year round. They seemed to last about as well as anything at the time...
 
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quote:
Originally posted by mph: You're operating under the common, but mistaken, belief that "20W" means "acts like a 20 weight when cold." The two numbers don't have anything to do with each other.
I'm operating under the belief that "x"W-"y" multiweight oils start with "x" weight base stocks to which VI improvers are added to maintain viscosity at the "y" weight when heated to a standardized "hot" temperature. Am I to understand from your dissertation that the rated "cold" viscosity is not based on the base stocks' viscosity at a standardized "cold" temperature? If so, what is it based on?
 
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It could be based on the lubricant's resistance to thicken when chilled. Lubricants with high VI's have that attribute. Therefore.....a single grade engine oil that is blended from a high VI base stock, may resist thickening when chilled well enough to pass an xW cold flow and cranking test. It is quite likely that a mono-grade SAE 30 with a VI of 115-125 could easly pass a 20W or 15W cold performance test allowing that oil to be sold as a 20W30 or 15W30. An SAE 20 engine oil with a high natural VI may pass a 10W cold flow and cranking viscosity test, but is not declared or labeled as a 10W20. The hoopla (there is that word again!)about group III mineral and PAO synthetics (I give) is that those base oils resist thickening very well when chilled. It is possible for a straight weight synthetic, (by any other name), to pass a very cold performance test. Straight weight "synthetic" SAE 50 becomes 15W50, SAE 40; 5W40, SAE 30; 0W30 and so on, without the use of VI improvers in the brew.
 
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