10W vs 10W-30 vs SAE 30 cylinder wear

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SAE 30 isn't really that thick at temps above 20 degrees F. Valvoline SAE 30 is about 2,300 Cst at 20 degrees F.

A typical 5w-30 at 0 degrees F is thicker at around 2,500 Cst.

Anything above 20 or 30 degrees like G-Man eluded to would be safe and, per this little graph, maybe beneficial!

Now, if you live where it gets to 0 degrees or below, like the 15 below we see at least once every year or two, OUCH, Zilch, zip, nada, not a good idea.
 
Yes ..a 20 weight is typically a SAE 20 or 20w-20 ...but all 10w oils that I've ever seen are, in fact, 10w(20). That is, they're sold for the 10w properties and, additionally, although they are motor oils, they're used in transmissions.

How I loath the PDF format
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PZ LL 10w
TEST
METHOD
TYPICALRESULTS
SAE Viscosity Grade
SAE J300
15W-40
10W-30
10W
API Service Category
SAE J183
CI-4 PLUS, CI-4, CH-4, CG-4, CF-4, CF/SL
CI-4, CH-4, CG-4, CF-4,CF/SL
CF
Gravity
Specific @ 60°F(15.6°C)
ASTM D-287
0.881
0.875
0.877
°API
29.1
30.2
29.7
Pounds per Gallon
7. 35
7.28
7.33
Flash Point, °C(°F) Min.
ASTM D-92
205(400)
205(400)
205(400)
Pour Point, °C(°F).
ASTM D-97
–33 (-27)
-39 (-38)
–30(-22)
Color
ASTMD-1500
4.0
4.0
4.5
Viscosity
@ 40°C, cSt
ASTM D-445
118
78
38
@ 100°C, cSt
ASTM D-445
15.8
11.7
6.5
Viscosity Index
ASTM D-2270
136
144
120
High Temperature/High Shear Vis., cP
ASTM D-4683
4.3
3.5
2.4
Low Temperature Viscosity
Vis (cP) at Temperature (°C)
ASTM D-2602
6,400 @-20
6,500@-25
7,000 max @-25
Low-Temperature Pumping, cP. (°C)
ASTM D-4684
23,000 @-25
25,000@-30
60,000max @-30
Sulfated Ash Content, % wt.
ASTM D-874
1.3
1.3
Shear Stability, % Vis Loss
DIN Method
< 4.0
--
Total Base Number
ASTM D-2896
11
11
6 min

Typical Properties

Mobil Delvac Hydraulic 10W
SAE Grade 10W
Viscosity, ASTM D 445
cSt @ 40ºC 37.7
cSt @ 100ºC 6.1
Viscosity Index, ASTM D 2270 107
Sulfated Ash, wt%, ASTM D 874 0.5
Total Base #, mg KOH/g, ASTM D 2896 4.0
Pour Point, ºC, ASTM D 97 -30
Flash Point, ºC, ASTM D 92 232
Density @ 15ºC kg/l, ASTM D 4052 0.877


Delo 400

SAE Grade 10W-30 10W 20 30 40 50
Product Number 235200 235109 235117 235118 235120 235119
MSDS Number 6711 6711 6711 6711 6711 6711
API Gravity 30.6 30.6 30.7 29 28.9 28
Viscosity, Kinematic
cSt at 40°C
cSt at 100°C
70
11.1
55
7.0
68
8.9
105
12.1
146
14.9
225
18.4
Viscosity, Cold Crank, °C/Poise -25/64.4 -25/64.4 — — — —
Viscosity Index 150 109 104 104 102 98
Flash Point, °C(°F) 226(439) 221(430) 238(460) 242(468) 250(482) 254(489)
Pour Point, °C(°F) -42(-44) -32(-26) -30(-22) -31(-24) -33(-27) -31(-24)
Sulfated Ash, wt % 1.34 1.18 1.18 1.35 1.35 1.35
Base Number, ASTM D 2896 10.1 9.2 9.2 10.2 10.2 10.2
Phosphorus, wt % 0.126 0.114 0.114 0.116 0.116 0.116
Zinc, wt % 0.140 0.127 0.127 0.127 0.127 0.127

Delo 400 10w, 10w-30, 15w-40, 30, 40, etc
 
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has to do with HTHS and the fact that VII thickened oils DO NOT offer the anti scuff or film thickenes that a striaght grade will, IMHO a VII thickened oil acts only like the base vis oil BEFORE the VII is added in other words the 10/30 in this test acted like a striaght 10 wt would have IMHO maybe I'm wrong.
bruce


I agree with Bruce. Seems to me that while VII may add some to HTHS, the base oil carries most of the burden and that's why I shy away from 5w30, except Maxlife 5w30 which is HTHS of 3.5. Now Energy Conserving oils will also have temporary viscosity collapse in the VIIs to gain fuel mileage.

You could compromise between 10w30 and SAE 30 by mixing a 20W and a 10w40 to get something in the neighborhood of 15w30, which is a very good robust grade. Or 20w with enough 20w50 to get a 20w30 maybe.

As for viscosity of 10w and 20w, Valvoline's are (for their conventional):

10W is 6.5 cSt
20W is 8.12 cSt

I can get the 20W here at Murrays Auto and have 8 qts in my stash, but the 10w I am told is only available in big buckets, probably have to order from NAPA.
 
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As I see the graph, it appears the oils wear converges as the temps heat to 212F, then diverge as the temps approach and go beyond 302F. I assume the wear for the lower viscosity oils at low temps is due to the piston skirt to cylinder wall clearances being a tad larger on a diesel vs a gasoline engine, making it harder for the thinner oil to lubricate. I would also guess that piston dome temps and skirt temps are greater on a diesel engine given the much higher compression and heat content of the diesel fuel. I don't know what the piston temps are on the diesels, but a 454 CU IN engine was tested and showed 500-600F on the dome and 300F on the skirt. Do you know where the temp probes were imbedded for this test? Is this an average for top to bottom of piston travel?
grin.gif
 
Quote:



.but all 10w oils that I've ever seen are, in fact, 10w(20).





I hadn't noticed that, so I checked three of them and they would all qualify as 10W-20 oils as long as the HTHS was over 2.6. HTHS wasn't listed.
 
If any body needs straight 10w...I can get Cenex 10w HDEO...in my neck of the woods...Apparently there are still some "old-school" farmers in Nebraska that run 10w in January and February when for about 3 weeks we get a cold spell...Highs never get above 20f...lows are below zero...at the local coop they also sell 20w HDEO...and in the winter time the lobby of the coop is stacked full of 10w and 20w...At the local CarQuest they sell 20w...I will stop by today and check out specs on it...it is CarQuest brand oil made by Ashland...by the way if I had a 5w-20 spec'd car I would consider 20w in the summer...
 
IMO, we can't extrapolate current results from this test that was done almost 15 years ago.

If we ASSuME we can, then give me a good synthetic 10w30 with no VII and call it a day.
 
Quote:


has to do with HTHS and the fact that VII thickened oils DO NOT offer the anti scuff or film thickenes that a striaght grade will, IMHO a VII thickened oil acts only like the base vis oil BEFORE the VII is added in other words the 10/30 in this test acted like a striaght 10 wt would have IMHO maybe I'm wrong.
bruce


Redline oil gets into the shearing under pressure on their web site
 
Quote:


IMO, we can't extrapolate current results from this test that was done almost 15 years ago.

If we ASSuME we can, then give me a good synthetic 10w30 with no VII and call it a day.


I wouldn't put my money on it as fact.
 
Quote:


SAE 30 isn't really that thick at temps above 20 degrees F. Valvoline SAE 30 is about 2,300 Cst at 20 degrees F.

A typical 5w-30 at 0 degrees F is thicker at around 2,500 Cst.

Anything above 20 or 30 degrees like G-Man eluded to would be safe and, per this little graph, maybe beneficial!

Now, if you live where it gets to 0 degrees or below, like the 15 below we see at least once every year or two, OUCH, Zilch, zip, nada, not a good idea.


That is why the proper choice of viscosity for the temps upon startup is a good idea.
 
Quote:


Quote:



.but all 10w oils that I've ever seen are, in fact, 10w(20).





I hadn't noticed that, so I checked three of them and they would all qualify as 10W-20 oils as long as the HTHS was over 2.6. HTHS wasn't listed.


Right because a 20 weight has a 100C viscosity from 5.6 to <9.3. So yes both 10w and 20w are 20 weights if they meet the HTHS.
 
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Ill stick to multi grade myself...my engine isnt worth the risk.




Ditto for me especially since "most wear occurs at start-up". I might consider using a straight 30 wt. (in a 5w30 spec'd vehicle) if I were driving cross-country or some other situation with very few cold starts.
 
Quote:


Here's an advanced "course" on polmeric viscosity index improver's effect on lubrication. There are many others as well.
http://www.cheric.org/PDF/KARJ/KR15/KR15-3-0117.pdf




"This is the reason that the load carrying
capacity of lubricant with VII containing long chained
polymeric molecules is far smaller than pure base oil under
the condition of the same applied load as shown in the
work by Bird et al. (1987) and Harris (1977)."

"The load capacities of monograde oil (case I and II) are higher than those of VII added lubricant (case III and IV) under the same contact condition by ranging from ~10 nm to ~40 nm of film thickness scale."

JAG, thanks for the link. Think I'll stick to my synthetic, out-dated grade of 10w30
grin.gif
This also supports straight weight over VI improved grades.
 
There are some gen sets in Alaska that are used in emergency communications and they are careful to keep the oil warm all the time so they can use straigh 30 weight oil. The maintenance people claim it's worth the trouble keeping them warm. These engines do nothing most of the time but when called upon are ramped up to 3600rpm in 60 seconds and come to full load in 180 seconds to take over from the battery system. They only run at 3600rpm usually fully loaded. They are either feeding the grid or charging the batteries, then shut down. These engines live on Delo 400 30W and there is nothing you can do to get these guys to use a multi-grade oil.
 
Quote:


has to do with HTHS and the fact that VII thickened oils DO NOT offer the anti scuff or film thickenes that a striaght grade will, IMHO a VII thickened oil acts only like the base vis oil BEFORE the VII is added in other words the 10/30 in this test acted like a striaght 10 wt would have IMHO maybe I'm wrong.
bruce



I think you are right. And I think what you've said points to why the RS4 with its fuel dilution issue shows such awful wear with VII laden 5w40 oils that meet VW's specs. Aromatic damage to the VI improvers only accentuates the oil's inability to cope with high temp/high shear situations, hence the increased wear.





That makes a lot of sense.

If you also notice, Redline's oils have very low VI#'s.

So I guess most 0w-20's and even 10w-30's contain some amount of VII's?
 
Hold on, guys..... Note the fine print at the lower left corner of the graph. The designation for the tested engine, "OM616" refers to the four cylinder Mercedes-Benz passenger car engine of the seventies to early eighties and not marketed here since 1983. Oelmotor, is what M-B calls a diesel. Shed any light on the report?
 
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