This statement frequently pops up on this site, but I don't believe it. Yet, if true, it just gives me one more reason to support my aversion to 5w30.
Does 5w30 really generally sheer down to 20 wt?
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Some conventional oils do. Now is this because of VII shearing or???
I have a notion (that is far from "the Truth), that the SM rated 5-30's hold grade much better than the older versions.
Originally Posted By: Titan
I have a notion (that is far from "the Truth), that the SM rated 5-30's hold grade much better than the older versions.
I agree with Titan. I believe when the 5W-20 SL oils appeared they were more shear resistant than "convential" 5W-30 SL oils. Partially due to the lower spread in viscosity and the more stingent standards Ford set for that oil. Better base oils appeared to be used and who knows about the additives
in 5W-20 vs 5W-30 at that time. With the advent of SM 5W-30's and the use of better base oils and possibly better additives to meet the SM requirements "convential" 5W-30 seem to have improved in the shearing "department".
Whimsey
I have a notion (that is far from "the Truth), that the SM rated 5-30's hold grade much better than the older versions.
I agree with Titan. I believe when the 5W-20 SL oils appeared they were more shear resistant than "convential" 5W-30 SL oils. Partially due to the lower spread in viscosity and the more stingent standards Ford set for that oil. Better base oils appeared to be used and who knows about the additives
Whimsey
30 weight starts at 9.3 cSt. The thinnest 30 on the market I know of starts at 9.7 cSt. Most are 10.4-10.6, some as high as 12.9.
Conversely, almost every 5W-20 on the market is between 8.0 cSt and 9.1 cSt, usually 8.4-8.6, so not far behind the 30 weights viscosity wise.
Conversely, almost every 5W-20 on the market is between 8.0 cSt and 9.1 cSt, usually 8.4-8.6, so not far behind the 30 weights viscosity wise.
Looking at some recent UOAs posted here, it appears the answer is no for synthetics and yes for dino. Of the 10 recent synthetic UOAs I looked at, the average 100C cSt was 10.54 at an average mileage of 5800. The 10 dino UOAs produced an average 100C cSt of 8.8 (and only 2 of the 10 above 9.0) at an average mileage of 2870. Obviously this isn’t super scientific, but there appears to be a trend. When looking for the 5W30 UOAs, I had to go further back to find 10 dino ones (there were quite a few more Synthetic 5W30 UOAs than dino ones).
One more note: Four of the ten Synthetic UOAs was on GC, which could have skewed the data some since it’s a “heavy” 30 wt. However, none of the 10 Synthetics had a 100C cSt of less than 9.1.
One more note: Four of the ten Synthetic UOAs was on GC, which could have skewed the data some since it’s a “heavy” 30 wt. However, none of the 10 Synthetics had a 100C cSt of less than 9.1.
Originally Posted By: Whimsey
Originally Posted By: Titan
I have a notion (that is far from "the Truth), that the SM rated 5-30's hold grade much better than the older versions.
I agree with Titan. I believe when the 5W-20 SL oils appeared they were more shear resistant than "convential" 5W-30 SL oils.... With the advent of SM 5W-30's and the use of better base oils and possibly better additives to meet the SM requirements "convential" 5W-30 seem to have improved in the shearing "department".
Whimsey
Well stated! You hit the nail on the head. I agree 100%
Technology has made the product better. MUCH better. With SM oils, I wouldn't worry about shear-down much at all except for the el-cheapo products. Any name brand SM oil will provide excellent service for 5K drains w/o the worry of shearing.
Originally Posted By: Titan
I have a notion (that is far from "the Truth), that the SM rated 5-30's hold grade much better than the older versions.
I agree with Titan. I believe when the 5W-20 SL oils appeared they were more shear resistant than "convential" 5W-30 SL oils.... With the advent of SM 5W-30's and the use of better base oils and possibly better additives to meet the SM requirements "convential" 5W-30 seem to have improved in the shearing "department".
Whimsey
Well stated! You hit the nail on the head. I agree 100%
Technology has made the product better. MUCH better. With SM oils, I wouldn't worry about shear-down much at all except for the el-cheapo products. Any name brand SM oil will provide excellent service for 5K drains w/o the worry of shearing.
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Originally Posted By: TallPaul
This statement frequently pops up on this site, but I don't believe it. Yet, if true, it just gives me one more reason to support my aversion to 5w30.
Well, although I agree that NOW (and surely for a few years) there are better base stocks, I think you need to read into the inversed inference....
Since the mid to late 70's most of your engines (all but a few relatively big push rod jobbies) DID run a decent amount of their life on sheared 5w-30 oil. I'd say that this continued through the late 90's ..maybe later.
Oh, sorry, we haven't had a 5w-20 argument for a while. I guess the hysteria is over. My bad
This statement frequently pops up on this site, but I don't believe it. Yet, if true, it just gives me one more reason to support my aversion to 5w30.
Well, although I agree that NOW (and surely for a few years) there are better base stocks, I think you need to read into the inversed inference....
Since the mid to late 70's most of your engines (all but a few relatively big push rod jobbies) DID run a decent amount of their life on sheared 5w-30 oil. I'd say that this continued through the late 90's ..maybe later.
Oh, sorry, we haven't had a 5w-20 argument for a while. I guess the hysteria is over. My bad
Originally Posted By: TallPaul
This statement frequently pops up on this site, but I don't believe it.
All you need to do is spend time reading UOAs. Brian's post in this thread shows this. There's no such thing as non-synthetic 0W-30 oils for good reason. 5W-30 non-conventional is as far a stretch for 30 weight oils as is reasonable so far. Synthetics can yield 10W-30 without any viscosity index improvers...Amsoil ACD is an example.
This statement frequently pops up on this site, but I don't believe it.
All you need to do is spend time reading UOAs. Brian's post in this thread shows this. There's no such thing as non-synthetic 0W-30 oils for good reason. 5W-30 non-conventional is as far a stretch for 30 weight oils as is reasonable so far. Synthetics can yield 10W-30 without any viscosity index improvers...Amsoil ACD is an example.
About a year ago Valvoline conducted a survey of various 5W-30 conventional products on shear stability and stay-in-grade performance. We went to our local Advance Auto Parts and purchased quarts of the products listed below. We noted that each product was currently labeled with the API SM donut and carried the ILSAC GF-4 starburst. I have included the results of the ASTM D6278 Kurt Orbahn (Bosch diesel injector) test which is typically used to evaluate stay-in-grade shear performance for engine oils. The current API requirement for BOI or VGRA (baseoil interchange or viscosity grade readacross) purposes for a 5W-30 stay-in-grade limit is 8.5cSt. Any 5W-30 that shears below this viscosity does not meet this API requirement for BOI or VGRA. The 8.5cSt viscosity limit is actually below the SAE J300 lower viscosity limit of 9.3cSt. for a SAE 30 grade because the Kurt Orbahn test is more severe than the Seq VIII engine test used to evaluate shear stability when running an API oil licensing program. European ACEA requirements are more severe requiring a higher performance level and a stay-in-grade pass uses the SAE J300 viscosity lower limits. So a 5W-30 must retain a minimum of 9.3cSt after the test. Out of all the oils tested, only the Valvoline oil showed the ACEA level of stay-in-grade performance.
Product Name Valvoline Premium Conv, Castrol GTX, Havoline,Mobil Clean 5000, Quaker State, Pennzoil
SAE Grade all 5W-30
Kinematic Viscosity @40C,cSt: 60.17, 60.59, 54.90, 60.16, 62.46, 61.07
Kinematic Viscosity @100C,cSt: 10.66, 10.59, 9.71, 10.55, 10.43, 10.49
ASTM D6278 Kurt Orbahn Shear (30 pass)
Kin Vis @ 100C, cSt after Shear: 9.42, 9.04, 8.89, 8.8, 8.68, 8.63
Product Name Valvoline Premium Conv, Castrol GTX, Havoline,Mobil Clean 5000, Quaker State, Pennzoil
SAE Grade all 5W-30
Kinematic Viscosity @40C,cSt: 60.17, 60.59, 54.90, 60.16, 62.46, 61.07
Kinematic Viscosity @100C,cSt: 10.66, 10.59, 9.71, 10.55, 10.43, 10.49
ASTM D6278 Kurt Orbahn Shear (30 pass)
Kin Vis @ 100C, cSt after Shear: 9.42, 9.04, 8.89, 8.8, 8.68, 8.63
Very cool. Thanks for the data. Welcome and please stick around and continue to educate/inform!
Valvman I would guess you work at Ashland oil being in kentucky. Any info you would like to share on your oils . I will listen.
Originally Posted By: MGregoir
30 weight starts at 9.3 cSt. The thinnest 30 on the market I know of starts at 9.7 cSt. Most are 10.4-10.6, some as high as 12.9.
Conversely, almost every 5W-20 on the market is between 8.0 cSt and 9.1 cSt, usually 8.4-8.6, so not far behind the 30 weights viscosity wise.
Is the thinnest 30 weight you speak of Havoline DS?
30 weight starts at 9.3 cSt. The thinnest 30 on the market I know of starts at 9.7 cSt. Most are 10.4-10.6, some as high as 12.9.
Conversely, almost every 5W-20 on the market is between 8.0 cSt and 9.1 cSt, usually 8.4-8.6, so not far behind the 30 weights viscosity wise.
Is the thinnest 30 weight you speak of Havoline DS?
Thank you for the data Valvman. You are about to become a very popular member for sharing real expertise. Please stick around.
Thank you Valvman for the test data.
I am naturally skeptical about a test done by a Mfr. that shows their own product superior.
I don't see patterns like that from the UOAs on this site.
I am naturally skeptical about a test done by a Mfr. that shows their own product superior.
I don't see patterns like that from the UOAs on this site.
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