Kubota oil

[TheOldHokie]

The 20W is for like a 20w50 oil, for the 20W part. SAE 20 is just 20 weight oil. Neither above nor on line could I find any spec on VI or a lower temperature spec for it to know what xxw20 it is.

The first number is NOT the grade of the oil. It is for its specification at some lower temperature. The 2nd number in the xxwyy spec is the grade of the oil at operating temperature, e.g. 100 C.

I've read where some of you have called 5w30 oil a 5 grade but acts like a 30 grade at operating temperature. No. It's a 30 grade oil that meets the low temperature spec for a 5 grade and likely has about 140-190 VI.

You are just digging your hole deeper.

Look at the J300 table. Column one is the grade number. SAE J300 (2015) defines six winter (W) grades and eight summer (high temperature) grades.

The winter grades are 0W, 5W, 10W, 15W, 20W, and 25W
The summer grades are 8, 12, 16, 20, 30, 40, 50, and 60

An oil that only meets the low temperature requirements is a W monograde - SAE 10W for example.

An oil that meets only the high temperature requirements is a summer monograde = e.g SAE 30

A multi-grade oil is an oil that meets BOTH a high temperature grade requirement and a low temperature grade reguirement. Multigrades are written by concatenating the two grade numbers with the winter grade written first followed by the summer grade - e.g. SAE 10W30.

There is no grade 0, 5, 10, or 15 in the current specification. SAE 10 used to exist but was removed decades ago and as far as I know the others were never defined. Grade 16 was added in 2013 and grades 8 and 12 in 2015. The SAE has provided for a future grade 4 if needed.

Dan

 

[RalphVa]

You're making a mountain out of a mole hill. The first number is the grade for starting at low temperature. Second # is the grade when at operating temperature. The single grade oils meet some sort of xxwyy spec but without VI to calculate what that lower temperature vis value is, you cannot tell what the "xx" would be. The single grade oils just aren't tested for a low temperature spec. I don't know why they even exist.

 

[TheOldHokie]

You're making a mountain out of a mole hill. The first number is the grade for starting at low temperature. Second # is the grade when at operating temperature. The single grade oils meet some sort of xxwyy spec but without VI to calculate what that lower temperature vis value is, you cannot tell what the "xx" would be. The single grade oils just aren't tested for a low temperature spec. I don't know why they even exist.

I am trying to provide accurate descriptions of what a grade label means. You are throwing around numbers and requirements that simply dont exist. The tests and numbers are in the table and thats all you need to know. Tests measure kinematic and absolute viscoity at various temperatures. VI is not used to grade engine oils although by their very definition multigrade oils will have higher VIs than monogrades.

Monogrades meet the viscosity requirements of exactly one of the winter or one of the summer grades.

Multigrades meet both a winter and summer grade requirement using the exact same specifications as monograde oils and the grade label tells you which two. For example SAE 15W40 oil meets the requirements for both grade SAE 15W and grade SAE 40. The J300 table tells you exactly what those requirements are. It is as simple as that and nothing more.

Monograde oils are special in that they can not contain any VI modifiers. They aren't "just not tested" - they wont pass if tested. If they could pass they would be tested and labeled as multi-grades. Their traditional advantage was longer time in grade than the corresponding multigrades. With recent improvements in the shear resistance of VI additives that advantage is eroding and they are rapidly disappearing from the market. Their main advantage today is they can be formulated with Group II and lower end Group III base stocks and are cheaper to make.

Dan

 

[Mark_BX25D]

The tests and numbers are in the table and thats all you need to know. Tests measure kinematic and absolute viscoity at various temperatures. VI is not used to grade engine oils although by their very definition multigrade oils will have higher VIs than monogrades.

Monogrades meet the viscosity requirements of exactly one of the winter or one of the summer grades.

Multigrades meet both a winter and summer grade requirement using the exact same specifications as monograde oils and the grade label tells you which two. For example SAE 15W40 oil meets the requirements for both grade SAE 15W and grade SAE 40. The J300 table tells you exactly what those requirements are. It is as simple as that and nothing more.

Monograde oils are special in that they can not contain any VI modifiers. They aren't "just not tested" - they wont pass if tested. If they could pass they would be tested and labeled as multi-grades. Their traditional advantage was longer time in grade than the corresponding multigrades. With recent improvements in the shear resistance of VI additives that advantage is eroding and they are rapidly disappearing from the market. Their main advantage today is they can be formulated with Group II and lower end Group III base stocks and are cheaper to make.

That post ought to be a sticky. That is the most concise, the clearest explanation of oil grades that I think I've ever seen.

Thank you.

 

[TheOldHokie]

That post ought to be a sticky. That is the most concise, the clearest explanation of oil grades that I think I've ever seen.

Thank you.

You are welcome but thats too kind.

Dan

 

[RalphVa]

There's not enough information on the plain SAE grades to determine what their cold temperature viscosities would be. Need VI or a 2nd viscosity value to do this. If they have no VI improver, they're probably only 95 VI, which is typically what is made off the final treatment usually dewaxing.

xxwyy oils from Group I and likely II oils have VI improvers to get their VIs up to around 140. Group III oils likely are that level already without VI improver. Group III and IV would not need any pour point depressant to get pours to -40 F/C.

By comparison, synthetic oils (Group IV) have VIs up around 190.

 

[TheOldHokie]

There's not enough information on the plain SAE grades to determine what their cold temperature viscosities would be.

Blenders provide KV40, KV100, and viscosity index in their data sheets. Its not hard to find - just look.
Then plug that into your favorite online viscosity graphing tool. For example:

Valvoline All Fleet SAE 30

KV100 11.0
KV40: 87
VI: 113

Valvoline All Fleet SAE 40

KV100: 14.5
KV40: 138
VI: 105

 

[RalphVa]

The ASTM equation is log log(cs+.7)=a+b log(t) Gives you a straight line for cs vs. temp. Can calculate viscosity at starting temp. Think it's absolute value of temp.

The above plot clearly shows the advantage of 5w30 vs. SAE 30.

I used this kind of information to compute relative cranking speeds for various oils. Cranking speed is proportional to sq rt of cranking viscosity. This is why I say 15w40 oil is goo.

No point in doing this for SAE 20 because you cannot get it in diesel formulation. It is likely more gooey than 15w40 at cranking temperatures.

 

[TheOldHokie]

The ASTM equation is log log(cs+.7)=a+b log(t) Gives you a straight line for cs vs. temp. Can calculate viscosity at starting temp. Think it's absolute value of temp.

The above plot clearly shows the advantage of 5w30 vs. SAE 30.

I used this kind of information to compute relative cranking speeds for various oils. Cranking speed is proportional to sq rt of cranking viscosity. This is why I say 15w40 oil is goo.

No point in doing this for SAE 20 because you cannot get it in diesel formulation. It is likely more gooey than 15w40 at cranking temperatures.

People say the darndest things.

Don't get me wrong - I am not advocating for SAE 20 in anything but the recommended lubricants list for my L3901 says SAE 20 is acceptable for ambients between -14C and 25C. The G2160 and B7200 say its OK between 0C to 25C. I had no trouble finding SAE 20 diesel oils but did not find any with with a CK-4 service rating so that would leave the L3901 out. This Delo 400 would however meet the OEM requirements of the other two. Also available in the Kubota approved SAE 10W for use in the cold months when temps dip below freezing.

Dan

 

[RalphVa]

Be interesting to compare the SAE 20 cranking viscosity with the one for 15w40.

I could not contact ASTM to find out the reason for the upper temperature limits. All oils in water cooled engines operate at around 210 F as set by coolant at 195 F, typically. The lower temperature limit makes sense because at some point, the stuff just won't pump until the oil pump warms it up by churning at it. In meantime, the valve gear and other stuff is smoking inside.

 

[TheOldHokie]

L

Be interesting to compare the SAE 20 cranking viscosity with the one for 15w40.

I could not contact ASTM to find out the reason for the upper temperature limits. All oils in water cooled engines operate at around 210 F as set by coolant at 195 F, typically. The lower temperature limit makes sense because at some point, the stuff just won't pump until the oil pump warms it up by churning at it. In meantime, the valve gear and other stuff is smoking inside.

Where do you get your information?

Engine oils operate at temperatures much higher than 100C (212F) The oil temperature gauge on my twin turbo BMW easily hits 260F on a hot day and that is at the oil cooler inlet. Inside journal bearings the temperature is higher and the oil is being heavily sheared. That is the reason for the 150C (302F) High Temperature High Shear (HTHS) viscosity requirement.

Dan

 

[RalphVa]

L

Where do you get your information?

Engine oils operate at temperatures much higher than 100C (212F) The oil temperature gauge on my twin turbo BMW easily hits 260F on a hot day and that is at the oil cooler inlet. Inside journal bearings the temperature is higher and the oil is being heavily sheared. That is the reason for the 150C (302F) High Temperature High Shear (HTHS) viscosity requirement.

Dan

I don't remember where I got the sq rt relationship for cranking speed. Online somewhere from some bench test results.

I worked for 31 years in the lube oil industry and put together computer tools for us engineers to use in our office and in the field. Before, we had plots in a little notebook that were hard to read, etc. Most of the mathematical relationships came from the ASTM. Some came from our research people in Sarnia, Ontario.

I put the SAE 20 vis numbers into the same spreadsheet where I'd calculated various oils from using the Visual Basic functions and subroutines in Excel from our tools. It's cold crank vis @ -4 F is lower than that for 15w40: 6200 vs. 7000. So, it's less gooey than 15w40. Its vis @ 230 F (more typical non turbo temp probably) is 7 vs. 11 for 15w40. Vis for an SAE 30 at that temp is 8. A 0w30's vis is 10, almost as high as the 15w40's. Lower cold crank vis than SAE 20 (e.g. 6200 at -31 F vs. 6200 @ -4 F for SAE 20).

 

[RalphVa]

The vis of oils @ 260 F: 15w40 = 8; 10w40 = 9; 5w40 = 9; 0w30 = 7; 0w40 = 9; SAE 20 = 5

@ 230 F: 15w40 = 11; 10w40 = 12; 5w40 = 12; 0w30 = 10; 0w40 = 12; SAE 20 = 7

The ASTM may have some sort of typical plot of oil temperature vs. outside temperature and some breakpoint vis that they use to compute those maximum ambient temperatures. Don't know how much oil temperature varies with outside temperature in water cooled engines. Probably not a lot at anything between about 70 F and 100 F. Suspect those maximum ambient temps apply mostly to air cooled engines.

 

[Dieseldonato]

Be interesting to compare the SAE 20 cranking viscosity with the one for 15w40.

I could not contact ASTM to find out the reason for the upper temperature limits. All oils in water cooled engines operate at around 210 F as set by coolant at 195 F, typically. The lower temperature limit makes sense because at some point, the stuff just won't pump until the oil pump warms it up by churning at it. In meantime, the valve gear and other stuff is smoking inside.

You do realize at normal temps even down to 0*f this is total bs, and yes I've had the valve covers off diesel engines at those temps and cranked them. 15w40 pumps just fine. There's no smoking valves, no burning gears. Your -40* is impractical comparison for 90% of planet earth.

 

[TheOldHokie]

You do realize at normal temps even down to 0*f this is total bs, and yes I've had the valve covers off diesel engines at those temps and cranked them. 15w40 pumps just fine. There's no smoking valves, no burning gears. Your -40* is impractical comparison for 90% of planet earth.

The smoking valve train story os not representative of teal life. . -40C (also -40F) is a test temperature used as an extreme for testing purposes and not meant to be reflective of normal operating condition.

That said, modern oil technology has evolved to the point where 15W is low performance and there are many parts of the country where it provides borderline protection. There are better choices available.

Dan

 

[ejb11235]

The attached file contains the javascript for the Widman calculator that Hokie is using, in case you're curious. It's not very good code, btw.

 

[TheOldHokie]

If anybody wants to see the source code for the Widman oil calculator that Hokie is using, I've attached the file as a text file. It has the HTML and embedded javascript for the calculator in it.

Its uses the ASTM D341 algorithm. D341 lets you calculate kinematic viscosity at any given temperature using the known viscosity at 40C and 100C.

Widman is just a nice graphing tool that uses the known viscosities at 40C and 100C to plot the viscosity curve across a range of temperatures. That gives you a good visual picture of the differrences in the oils.

Dan

 

[RalphVa]

Here's the code from our tools. You just put it into Visual Basic part of Excel.


Global Const FNULL = -3.4E+38

Global Const DNULL = -3.4E+38

Global Const TRF = 459.67

Function third_cs#(ByVal Vis1#, ByVal TempF1#, ByVal Vis2#, ByVal TempF2#, ByVal TempF3#)
' ******************** THIRD_CS **************************
' Function for obtaining a third Centistoke viscosity, given two
' input values and temperatures.
' input: centistoke viscosity
' temperature measured at, F
' centistoke viscosity
' temperature measured at, F
' 3rd temperature measurement desired, F
' returns: 3rd Centistoke viscosity
' Date: April 30, 1990 Author: Ralph R. Hall
' RevDate: 14 Sep 94 Author: Ralph R. Hall
' The ASTM equation is log log(cs+.7)=a+b log(t), the logs are
' base 10. The .7 constant is not .7 at low cs values.
' The revision was included based on pg. 139 of the ASMTM
' manual, giving the equation in D 341 for going below 2
' Cs viscosity.
' *******************************************************
' TEMPERATURES MUST BE DEGREES F
Dim dAcon#, dBcon#, dVm3#

If Vis1 > Vis2 And TempF1 > TempF2 Then
third_cs = FNULL
ElseIf TempF1 = TempF2 Then
third_cs = Vis2
ElseIf TempF3 = TempF1 Then
third_cs = Vis1
ElseIf TempF3 = TempF2 Then
third_cs = Vis2
Else
Call astm_d341_cons(Vis1, TempF1, Vis2, TempF2, dAcon, dBcon)
dVm3 = dAcon + dBcon * log10(TempF3 + TRF)
third_cs = astm_d341_vm(dVm3, False)
End If
End Function

Sub astm_d341_cons(Vis1#, TempF1#, Vis2#, TempF2#, Acon#, Bcon#)
' Determines ASTM D341 slopes from 2 vis values &
' two temperature values.
' Inputs:
' o 1st viscosity, cS
' o 1st temperature, F
' o 2nd viscosity, cS
' o 2nd temperature, F
' Outputs: A constant and B constant in the equation
' Vm = A + B log T
' By Ralph R. Hall Date: 10 November 1996
Dim dVm1#, dVm2#

dVm1 = astm_d341_vm(Vis1, True)
dVm2 = astm_d341_vm(Vis2, True)
Bcon = (dVm2 - dVm1) / (log10(TempF2 + TRF) - log10(TempF1 + TRF))
Acon = dVm2 - Bcon * log10(TempF2 + TRF)
End Sub

Function astm_d341_vm#(ByVal VisOrZ#, Direction%)
' gives an ASTM D341 "vis modulus" from vis (Direction = True)
' or cS value from vis modulus (Direction = False)
' Input: centistokes or vis modulus = loglog(cS + Zcon)
' Output: reverse
' By: Ralph R. Hall Date: 7 November 1996
Dim dVisPlusPt7#, dZval#, dVis#
Dim dCval#, dDval#, dEval#, dFval#, dGval#, dHval#, dPt7Sq#, dPt7Cube#

dCval = 0: dDval = 0: dEval = 0: dFval = 0: dGval = 0: dHval = 0
Select Case Direction
Case True
If VisOrZ <= 20000000# And VisOrZ >= 0.21 Then
dVis = VisOrZ
If dVis < 2# Then
dCval = Exp(-1.14883 - 2.65868 * dVis)
End If
If dVis < 1.65 Then
dDval = Exp(-0.0038138 - 12.5645 * dVis)
End If
If dVis < 0.9 Then
dEval = Exp(5.46491 - 37.6289 * dVis)
End If
If dVis < 0.3 Then
dFval = Exp(13.0458 - 74.6851 * dVis)
End If
If dVis < 0.24 Then
dGval = Exp(37.4619 - 192.643 * dVis)
End If
If dVis >= 0.21 And dVis < 0.24 Then
dHval = Exp(80.4945 - 400.468 * dVis)
End If
dZval = dVis + 0.7 + dCval - dDval + dEval - dFval + dGval - dHval
astm_d341_vm = log10(log10(dZval))
Else
astm_d341_vm = FNULL
End If
Case False
If VisOrZ <= DNULL Then
astm_d341_vm = FNULL
Else
dVisPlusPt7 = 10# ^ (10# ^ VisOrZ)
dVis = dVisPlusPt7 - 0.7
If dVis < 2# Then
dPt7Sq = dVis * dVis
dPt7Cube = dPt7Sq * dVis
dVis = dVis - Exp((-0.7487 - 3.295 * dVis) + 0.6119 * dPt7Sq - 0.3193 * dPt7Cube)
End If

astm_d341_vm = dVis
End If
End Select
End Function

 

[ejb11235]

Here's the code from our tools. You just put it into Visual Basic part of Excel.

Thanks!

 

[TheOldHokie]

The attached file contains the javascript for the Widman calculator that Hokie is using, in case you're curious. It's not very good code, btw.

Here is a link to an array of calculators. Good or bad code they work and all you have to is plug in a couple values.

Calculators | Widman International SRL

www.widman.biz

Dan