So a smaller bearing clearance requires a thicker viscosity oil? I thought that that was the other way around, or am I reading this worng bruce?
Why not use 0W-20 in a diesel engine?
- Thread starter Dr. T
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From my experience, yes, smaller diesels need a 40 weight engine oil as much as or even more than a larger Class 8 diesel engine. Many smaller diesel engines are evolutions of gasoline engine designs and horrendously under-bearinged vs. a true clean sheet of paper diesel design.
But yes, same violent explosion whether it is a large or small engine and bearing surface/oil whetted area is the name of the game in diesel engine design and longevity.
George Morrison, STLE CLS
But yes, same violent explosion whether it is a large or small engine and bearing surface/oil whetted area is the name of the game in diesel engine design and longevity.
George Morrison, STLE CLS
So actual RPM's have something to do with the equation, but not so much as underdesigned bearings, right? Now in the design department, are they to small surface area wise, or isn't there enough meat so to speak on the bearing construction itself that would tend to have the requirement of a 40 weight, instead of a 20 weight oil?
I'm asking all these because I've been wondering about this topic for a while myself, particularly since everything gasoline engine wise, seems to be heading in the direction of thinner based oils for the fuel economy issue. I do realize that diesels are more fuel efficient by design, but I'm sure that there are folks out there that would and will try to squeak out any little bit more that possibly could be had.
I'm asking all these because I've been wondering about this topic for a while myself, particularly since everything gasoline engine wise, seems to be heading in the direction of thinner based oils for the fuel economy issue. I do realize that diesels are more fuel efficient by design, but I'm sure that there are folks out there that would and will try to squeak out any little bit more that possibly could be had.
If I were going to attribute longer engine life across the board to 15w40 oils, I'd say it's more a product of the improved low temp lubrication of 15w40 vs SAE30 (or SAE40). Many fleets used to run SAE40, so those engines should have had longer engine lives vs SAE30 based on your theory.
And yes, those engines that did use 40W did have a longer life except for those engines in the northeast who experienced spun main bearings on cold weather start-up. i.e. the use of 30W in the north/northeast was a happy medium diesel engine oil.
Moreover, the introduction of not only the 40W operational viscosity but also the 15W cold flow characteristics on start-up was a huge operational plus. Very shortly after the widespread use of 15W-40 multiviscosity oils, I stopped seeing crushed connecting rod bearings (30W), scarred and spun main bearings from cold weather operation, scarred and gouged camshafts. i.e. a number of early engine overhaul causes were eliminated and engines began living longer.
In a lubrication engineer's training from day one, it is viscosity, viscosity, viscosity. And in engine oil it is "optimum viscosity"... When maximum engine and component life is the goal.
George Morrison, STLE CLS
Moreover, the introduction of not only the 40W operational viscosity but also the 15W cold flow characteristics on start-up was a huge operational plus. Very shortly after the widespread use of 15W-40 multiviscosity oils, I stopped seeing crushed connecting rod bearings (30W), scarred and spun main bearings from cold weather operation, scarred and gouged camshafts. i.e. a number of early engine overhaul causes were eliminated and engines began living longer.
In a lubrication engineer's training from day one, it is viscosity, viscosity, viscosity. And in engine oil it is "optimum viscosity"... When maximum engine and component life is the goal.
George Morrison, STLE CLS
[censored]... a 40 weight is better than a 30 weight in this case no matter what, because they both will shear, but the 40 weight will be higher in the end, and shear less overall. Except for cold starts, as mentioned... which is wear the most wear takes place in an engine... besides being held at WOT for an hour..
Ya can't beat seeing it with your own eyes.
Ya can't beat seeing it with your own eyes.
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If a 30wt is sheared down some and soot is kept in check, what do you get?
A heavy 20wt.
There is a member running a racing 0w-10, with bypass filtration, super long drains.
So who knows. 5w-30 is in the market, has been for years.
I don't see 5w-20 anytime soon.
But then again most syn oils carry CF ratings.
Harvey
A heavy 20wt.
There is a member running a racing 0w-10, with bypass filtration, super long drains.
So who knows. 5w-30 is in the market, has been for years.
I don't see 5w-20 anytime soon.
But then again most syn oils carry CF ratings.
Harvey
Originally Posted By: Dr. T
After reading the "Why do Euro cars use heavier oils post below" and the mention of diesel engines, I got to wondering: Why don't diesel's use 5-30 or even 0/5-20???
And maybe it's because it's a US grade thusfar...so what is the recommended grade for US diesel cars...eg. E class M-B or diesel Golf/Rabbits???
I have a better question, Why would anyone want to run a 5/20 oil in anything?
There is no benefit to the consumer, its just a novelty. A 5/30 will protect better but granted using either oil grade both engines will last a long time and most likely never know a difference but back to the question.
If a 5/30 protects better why use a 5/20?
Answer - The 5/20 gives an edge to the automobile maker when it comes to the EPA and gas milage, but we are talking fractions to the point, the consumer will never know. If the consumer cared about gas mileage all they would have to do is never exceed the speed limit and would increase their mileage 100s of times more then any 20 grade oil.
20 weight oil is made to satisfy the EPA at little detriment to the engine.
30 weight oil is made to satisfy long engine life at little detriment to the gas mileage.
After reading the "Why do Euro cars use heavier oils post below" and the mention of diesel engines, I got to wondering: Why don't diesel's use 5-30 or even 0/5-20???
And maybe it's because it's a US grade thusfar...so what is the recommended grade for US diesel cars...eg. E class M-B or diesel Golf/Rabbits???
I have a better question, Why would anyone want to run a 5/20 oil in anything?
There is no benefit to the consumer, its just a novelty. A 5/30 will protect better but granted using either oil grade both engines will last a long time and most likely never know a difference but back to the question.
If a 5/30 protects better why use a 5/20?
Answer - The 5/20 gives an edge to the automobile maker when it comes to the EPA and gas milage, but we are talking fractions to the point, the consumer will never know. If the consumer cared about gas mileage all they would have to do is never exceed the speed limit and would increase their mileage 100s of times more then any 20 grade oil.
20 weight oil is made to satisfy the EPA at little detriment to the engine.
30 weight oil is made to satisfy long engine life at little detriment to the gas mileage.
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Originally Posted By: Dr. T
After reading the "Why do Euro cars use heavier oils post below" and the mention of diesel engines, I got to wondering: Why don't diesel's use 5-30 or even 0/5-20???
And maybe it's because it's a US grade thusfar...so what is the recommended grade for US diesel cars...eg. E class M-B or diesel Golf/Rabbits???
diesels do spec 5w30...
EDIT: [censored], replied to a decade old question...
After reading the "Why do Euro cars use heavier oils post below" and the mention of diesel engines, I got to wondering: Why don't diesel's use 5-30 or even 0/5-20???
And maybe it's because it's a US grade thusfar...so what is the recommended grade for US diesel cars...eg. E class M-B or diesel Golf/Rabbits???
diesels do spec 5w30...
EDIT: [censored], replied to a decade old question...
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Originally Posted By: Jetronic
diesels do spec 5w30...
EDIT: [censored], replied to a decade old question...
That you did, but Imperial Oil did offer a 5w-30 as an Esso XD-3 about that time, and, as you point out, there are 5w-30 diesel oils, both in European passenger vehicles and in big rigs.
diesels do spec 5w30...
EDIT: [censored], replied to a decade old question...
That you did, but Imperial Oil did offer a 5w-30 as an Esso XD-3 about that time, and, as you point out, there are 5w-30 diesel oils, both in European passenger vehicles and in big rigs.
And again You do not differ between Acea 5w30 stay in grade oil And US made Ilsac one...
I don't know about the previous posters in this thread, by I assure you I know the difference.
I know that no ilsac oil will ever make it into my car or basement...
Originally Posted By: Jetronic
I know that no ilsac oil will ever make it into my car or basement...
+ sae grade lower than 30
I know that no ilsac oil will ever make it into my car or basement...
+ sae grade lower than 30
Originally Posted By: alarmguy
Originally Posted By: Dr. T
After reading the "Why do Euro cars use heavier oils post below" and the mention of diesel engines, I got to wondering: Why don't diesel's use 5-30 or even 0/5-20???
And maybe it's because it's a US grade thusfar...so what is the recommended grade for US diesel cars...eg. E class M-B or diesel Golf/Rabbits???
I have a better question, Why would anyone want to run a 5/20 oil in anything?
There is no benefit to the consumer, its just a novelty. A 5/30 will protect better but granted using either oil grade both engines will last a long time and most likely never know a difference but back to the question.
If a 5/30 protects better why use a 5/20?
Answer - The 5/20 gives an edge to the automobile maker when it comes to the EPA and gas milage, but we are talking fractions to the point, the consumer will never know. If the consumer cared about gas mileage all they would have to do is never exceed the speed limit and would increase their mileage 100s of times more then any 20 grade oil.
20 weight oil is made to satisfy the EPA at little detriment to the engine.
30 weight oil is made to satisfy long engine life at little detriment to the gas mileage.
Pretty much everything you said is wrong.
Originally Posted By: Dr. T
After reading the "Why do Euro cars use heavier oils post below" and the mention of diesel engines, I got to wondering: Why don't diesel's use 5-30 or even 0/5-20???
And maybe it's because it's a US grade thusfar...so what is the recommended grade for US diesel cars...eg. E class M-B or diesel Golf/Rabbits???
I have a better question, Why would anyone want to run a 5/20 oil in anything?
There is no benefit to the consumer, its just a novelty. A 5/30 will protect better but granted using either oil grade both engines will last a long time and most likely never know a difference but back to the question.
If a 5/30 protects better why use a 5/20?
Answer - The 5/20 gives an edge to the automobile maker when it comes to the EPA and gas milage, but we are talking fractions to the point, the consumer will never know. If the consumer cared about gas mileage all they would have to do is never exceed the speed limit and would increase their mileage 100s of times more then any 20 grade oil.
20 weight oil is made to satisfy the EPA at little detriment to the engine.
30 weight oil is made to satisfy long engine life at little detriment to the gas mileage.
Pretty much everything you said is wrong.
Originally Posted By: Kamele0N
Originally Posted By: Jetronic
I know that no ilsac oil will ever make it into my car or basement...
+ sae grade lower than 30
no, that I wouldn't say... If a 0w-20 or 5w-20 with hths of 2.9 or more existed I will consider it...
Originally Posted By: Jetronic
I know that no ilsac oil will ever make it into my car or basement...
+ sae grade lower than 30
no, that I wouldn't say... If a 0w-20 or 5w-20 with hths of 2.9 or more existed I will consider it...
Originally Posted By: Kamele0N
Originally Posted By: Jetronic
I know that no ilsac oil will ever make it into my car or basement...
+ sae grade lower than 30
I have a Camry which has traveled 300,000 MILES on ILSAC synthetics.
Originally Posted By: Jetronic
I know that no ilsac oil will ever make it into my car or basement...
+ sae grade lower than 30
I have a Camry which has traveled 300,000 MILES on ILSAC synthetics.
Originally Posted By: teven7492
GEORGECLS there's no such thing as 30w... its SAE-30.
My you're a clever little nit picker.
GEORGECLS there's no such thing as 30w... its SAE-30.
My you're a clever little nit picker.
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