Advantages of straight weight oil

Status
Not open for further replies.
Sorry, as usual, you are going to have to dumb your technical talk down to third grade level....

"syrup", "sweet spot", "sling" and "plastic" are new ones to me.
 
The only advantage I can think of would be better shear stability, which is not a concern in modern multi viscosity oils so shear stability is a moot point. The modern multi weight oils are without a doubt the better oil
 
>plastic
>syrup like state
>non-freezing climate

Slow down turt, think about what you're trying to say. Your imagination is running wild with all that sensationalism.

Originally Posted By: turtlevette

Yes. Absolutely.

I think I see a pattern here. You have different "fan clubs" here. Thick oil, thin oil, and no/low VIIs. There's really no changing of anyone's mind that's going to happen.



When you find yourself part of a fan club, by perhaps being hyper-reactional and anti-the-other-guy to people who disagree with your way of thinking for instance, then you know getting off course. Just accept that other people's reality will not correspond with your imagination.
smile.gif
 
Originally Posted By: Shannow
Originally Posted By: JHZR2
In an engine that is run for very long times, essentially steady-state, I dont see a reason to use anything different.


Also without the temporary shear of VIIs (I believe that) you can run thinner straight weight KV100s than multis...

As an example, this makes sense...moreso to me than a 0W-20 in a 10W-30 application.

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1174209


For those that haven't looked at the link, GMan ran 20W-20 in his car that is definitely not a beater, and posted UOAs.
 
Originally Posted By: fdcg27
Even the straight grades aren't really straight.
The basestock will have its own VI, so even a straight grade will be thinner at cold start than it's SAE viscosity grade might lead you to think.
In your climate, you could probably run a 20W-20 winters and a 30 in summers with no ill effects in most engines.


To be a "straight" weight, the lubricant has to be "Newtonian", and typically/always devoid of polymeric thickeners.

So, regardless of VI, a "straight" weight will have an identical viscosity regardless of shear rate for a given temperature...if your crankshaft is spinning 1,000 RPM, 3,000 RPM, or 20,000 RPM, at 100C, your 11cst 30 will be 11cst at every rpm increment.

Until multigrades were developed, the concept of "HTHS" was irrelevant (more so "not yet needed"), the normal viscosity classifications applied, and worked everywhere.

Multigrades with polymeric VII are non newtonian, and have different viscosities at the same temperature depending on the shear rate of the oil...the viscosity in your bearing at 1,000, 3,000, or 20,000 will be different.

That's why they introduced the HTHS concept, and requirement into J300...in the words of SAE
Quote:
To insure that polymer-containing oils do not create a situation in which the viscosity of the oil decreases to less than a specified limit, minimum values of HTHS viscosity are assigned to each of the non-W viscosity grades in Table 1. A
special situation exists regarding the SAE 40 grade. Historically, SAE 0W-40, 5W-40, and 10W-40 oils have been used
primarily in light-duty engines. These multigrade SAE 40 oils must meet a minimum HTHS viscosity limit of 3.5 mPa·s.
In contrast, SAE 15W-40, 20W-40, 25W-40, and 40 oils have typically been used in heavy-duty engines. The manufacturers of such engines have required HTHS viscosity limits consistent with good engine durability in high-load, severe service applications. Thus, SAE 15W-40, 20W-40, 25W-40, and single-grade 40 oils must meet a minimum HTHS viscosity limit of 3.7 mPa·s.


http://paservice.it/wp-content/uploads/2013/06/J300_201304.pdf

Out of interest, an SAE30 "newtonian" oil of around 10-11cst, KV100 typically will be around the 3.5-4cst at 150C...the original 2.9 for the 0, 5, and 10W-40s show how badly VII wasn't so good when developed...the current requirement for 3.5 for those same grades shows just how much modern VII have improved in recent years, in being able to meet those specs in (allegedly) every oil that you see holding the SAE ratings.

A High VI "straight weight", like Amsoil 30 can claim 10W, as it's cold temperature performance can meet those requirements...but it's still newtonian and can claim "straight"
 
Congratulations! You just graduated BITOG academy.

Originally Posted By: turtlevette
I think I see a pattern here. You have different "fan clubs" here. Thick oil, thin oil, and no/low VIIs. There's really no changing of anyone's mind that's going to happen.
 
I found this cold viscosity info in my old files when some of us were messing with the Delo SAE30. I can't remember who calculated the numbers. It may have been Audijunkie.

Delo SAE 30
100c 12.1cST
40c 105 cSt
10c(50f): 726.5 cSt
5c(41f): 1102.3
0c(32f): 1731
-5c(23f): 2825.4
-10c(14f): 4809.1
-15c(5f): 8575.7
-20c(-4f): 16100.7
 
Why waste this space.

The owners manual to my el cheapo YardMarchine non-self propelled mower says to use 5W30 synthetic for all temperature ranges. Why would anyone in this century bring up single weight oil. It is not for use in any passenger car made in the last 30 years.
 
Last edited:
Originally Posted By: Shannow
Originally Posted By: fdcg27
Even the straight grades aren't really straight.
The basestock will have its own VI, so even a straight grade will be thinner at cold start than it's SAE viscosity grade might lead you to think.
In your climate, you could probably run a 20W-20 winters and a 30 in summers with no ill effects in most engines.


To be a "straight" weight, the lubricant has to be "Newtonian", and typically/always devoid of polymeric thickeners.

So, regardless of VI, a "straight" weight will have an identical viscosity regardless of shear rate for a given temperature...if your crankshaft is spinning 1,000 RPM, 3,000 RPM, or 20,000 RPM, at 100C, your 11cst 30 will be 11cst at every rpm increment.

Until multigrades were developed, the concept of "HTHS" was irrelevant (more so "not yet needed"), the normal viscosity classifications applied, and worked everywhere.

Multigrades with polymeric VII are non newtonian, and have different viscosities at the same temperature depending on the shear rate of the oil...the viscosity in your bearing at 1,000, 3,000, or 20,000 will be different.

That's why they introduced the HTHS concept, and requirement into J300...in the words of SAE
Quote:
To insure that polymer-containing oils do not create a situation in which the viscosity of the oil decreases to less than a specified limit, minimum values of HTHS viscosity are assigned to each of the non-W viscosity grades in Table 1. A
special situation exists regarding the SAE 40 grade. Historically, SAE 0W-40, 5W-40, and 10W-40 oils have been used
primarily in light-duty engines. These multigrade SAE 40 oils must meet a minimum HTHS viscosity limit of 3.5 mPa·s.
In contrast, SAE 15W-40, 20W-40, 25W-40, and 40 oils have typically been used in heavy-duty engines. The manufacturers of such engines have required HTHS viscosity limits consistent with good engine durability in high-load, severe service applications. Thus, SAE 15W-40, 20W-40, 25W-40, and single-grade 40 oils must meet a minimum HTHS viscosity limit of 3.7 mPa·s.


http://paservice.it/wp-content/uploads/2013/06/J300_201304.pdf

Out of interest, an SAE30 "newtonian" oil of around 10-11cst, KV100 typically will be around the 3.5-4cst at 150C...the original 2.9 for the 0, 5, and 10W-40s show how badly VII wasn't so good when developed...the current requirement for 3.5 for those same grades shows just how much modern VII have improved in recent years, in being able to meet those specs in (allegedly) every oil that you see holding the SAE ratings.

A High VI "straight weight", like Amsoil 30 can claim 10W, as it's cold temperature performance can meet those requirements...but it's still newtonian and can claim "straight"


Very well stated. Thank you
thumbsup2.gif
 
Originally Posted By: Merkava_4
I gotta question for you guys: Why is SAE30 often labelled HD30 ?



HD30: High Detergency SAE 30 weight
In contrast with ND30, which is non-detergent.
There used to be a debate 40-50 years ago about detergent versus non-detergent oils. Some would say high detergent oils would not provide good wear protection, so ran non-detergent oils in their engines, and changed oil on short intervals to keep them from sludging.
 
Originally Posted By: Paul3637
Why waste this space.

The owners manual to my el cheapo YardMarchine non-self propelled mower says to use 5W30 synthetic for all temperature ranges. Why would anyone in this century bring up single weight oil. It is not for use in any passenger car made in the last 30 years.


I understand your point, but just because not many people use straight weight in motor vehicles anymore doesn't mean it's a useless discussion, not by any means. Some of us are here to learn, not just to accept things for what they are, and that's the spirit of this forum. For example, Shannow has provided some excellent information on this thread, specifically regarding the use of VIIs and viscosities changing under different shear on the oil.

Just my 2 cents.
 
Originally Posted By: Paul3637
Why waste this space.

The owners manual to my el cheapo YardMarchine non-self propelled mower says to use 5W30 synthetic for all temperature ranges. Why would anyone in this century bring up single weight oil. It is not for use in any passenger car made in the last 30 years.


You obviously haven't read a Subaru owner's manual up until the introduction of the FB engine a couple of years ago. My 2008 specifically allows SAE 30 and SAE 40 for desert areas or heavy duty use.

Ed
 
I've used amsoils straight 60 v-twin oil in my Harley and I liked it,other than cost. I'm going to use up what I've got left once summer hits.
 
Originally Posted By: A_Harman
HD30: High Detergency SAE 30 weight
In contrast with ND30, which is non-detergent.
There used to be a debate 40-50 years ago about detergent versus non-detergent oils. Some would say high detergent oils would not provide good wear protection, so ran non-detergent oils in their engines, and changed oil on short intervals to keep them from sludging.


Thanks for answering my question. I thought HD meant Heavy Duty.

Does the HD30 have more detergents than 10W-30 ?
 
Status
Not open for further replies.
Back
Top