Oil... how does it work? [split]

[bennyfizzle]

@Vovchandr

If it’s not the same scale, where is the rule that’s written that a thick fluid at low temp should be rated lower than a thin fluid at a high temp.

Otherwise you’re just making shit up by saying it’s not the same scale, because it is just ONE SCALE.

HOLY FUCK YOU ARE DUMB.

Travis explained this on the first page, go back and read it.

[Wayne64SS]

@bennyfizzle

HOLY FUCK YOU ARE DUMB.

Travis explained this on the first page, go back and read it.

THANK YOU.

[jdaniels]

Vlad, I like you… but did you eat paintchips as a kid (or currently)?

@Blackstone Labs

Straight Weight vs. Multi-Grade
Engine oil can be either a straight weight or a multi-grade viscosity. Originally, all oil was straight weight. Relatively few straight weights are manufactured today since most gas- or diesel-engine manufacturers recommend multi-grades. At operating temperature, a straight weight performs just as well as a multi-viscosity oil, and there is nothing wrong with using a straight weight. It’s just a simpler form of oil. Some diesel fleets still use straight weights, as do about half the piston aircraft operators.

The difference between multi-grade and straight-weight oil is simply the addition of a viscosity improving (VI) additive. The most common grade of automotive oil in use today is the 5W/30, which is a mineral oil refined with VI additives that leave it reading as an SAE 5W viscosity when cold, yet an SAE 30W when hot (210F). The advantage to the multi-weight is that when starting the engine, the multi-viscosity oil (with its thickness of an SAE 5W when cold), allows the engine to spin over more easily.

The most common diesel use oil is 15W/40. It is an SAE 15W oil with a VI additive that leaves it the thickness of an SAE 40 weight at operating temperature. What makes an oil a diesel-use oil (rather than automotive-use) is the level of additives used. Diesels require heavier levels of dispersant and anti-wear additives. These heavier additive levels are objectionable for automotive engines since they may interfere with the emission controls mandated by the EPA.

[Vovchandr]

I understand that.

But it allows to spin more easily then what 0w or 10w when it’s 5w?

How do you not see the inconsistency.

[bennyfizzle]

omg lol an SAE0W would ‘spin more easily’ than an SAE5W under the same exact conditions. naturally.

[Wayne64SS]

:rofl :rofl :rofl this is awesome.

[Vovchandr]

@bennyfizzle

It is a unit of measurement, yes, so we’ll put it this way.

I’ll try to relate the units in feet and inches:

20W50

20 feet @ 32F, 50 inches @ 212F.

It’s not the same unit of measurement between the two, of course the SAE rating will be lower in viscosity when hot on the same scale, but it’s NOT. This is why the 2nd number is HIGHER even though the oil is THINNER at that temperature vs. the first number.

Interesting you say they are not the same scale.

Maybe you can explain to me why 20 has the same cSt viscosity as 20w then.

If you guys can’t grasp that cold, thick oil should have high SAE numbers assigned but instead has low numbers, I can’t help you.

[jdaniels]

@Vovchandr

I understand that.

But it allows to spin more easily then what 0w or 10w when it’s 5w?

How do you not see the inconsistency.

It’s all relative. It allows it to spin more easily than a standard, non multi-grade oil of a given viscosity rating AT THOSE EXACT TEMPS.

Again:

5 @ cold = 5W30 @ cold

I just don’t get where you see an inconsistency. The first number is what the VI additive allows it to flow like when cold. It only affects the cold temp rating. All it’s saying is WHEN I’M COLD, I SPIN EASIER THAN I WOULD WITHOUT AN ADDITIVE. This DOES NOT mean that the oil is THINNER @ 32* – just that it’s thinner than it would be without the additive @ 32*.

[Vovchandr]

@jdaniels

It’s all relative. It allows it to spin more easily than a standard, non multi-grade oil of a given viscosity rating AT THOSE EXACT TEMPS.

Again:

5 @ cold = 5W30 @ cold

I just don’t get where you see an inconsistency. The first number is what the VI additive allows it to flow like when cold. It only affects the cold temp rating. All it’s saying is WHEN I’M COLD, I SPIN EASIER THAN I WOULD WITHOUT AN ADDITIVE. This DOES NOT mean that the oil is THINNER @ 32* – just that it’s thinner than it would be without the additive @ 32*.

But overall the spinning will be harder then when it’s warm.

I understand what 5w30 means I explained it in one of the first posts, I have a problem with the fact that cold has an assignment of 5 instead of lets say 50 making it 50w30.

If an oil spun easier while cold it would make it 45w30. If it spun harder when cold, 55w30.

It would be consistent between both numbers. If SAE says the higher the number the thicker, why is the thick cold oil rated lower then when it’s warm?

[jdaniels]

@Vovchandr

If you guys can’t grasp that cold, thick oil should have high SAE numbers assigned but instead has low numbers, I can’t help you.

The SAE ratings are done at a fixed temperature. The oil being cold is irrelevant to the rating itself. It’s just a number, I don’t know what else to tell you.

[Vovchandr]

@jdaniels"

The SAE ratings are done at a fixed temperature. The oil being cold is irrelevant to the rating itself. It’s just a number, I don’t know what else to tell you.

The ratings are done at two fixed temperatures when it’s a multigrade.

If it only has 1 number, it means it was only tested at 210 and never tested at 32.

[jdaniels]

@Vovchandr

The ratings are done at two fixed temperatures when it’s a multigrade.

If it only has 1 number, it means it was only tested at 210 and never tested at 32.

The number itself is derived from the high temperature test, that’s what you’re missing. The numbers are all relative to the high temperature rating of a standard fixed weight oil.

[Vovchandr]

@jdaniels

The number itself is derived from the high temperature test, that’s what you’re missing. The numbers are all relative to the high temperature rating of a standard fixed weight oil.

I understand that. Where is the miscommunication?

Again, I’ll bring the honey and see if I follow your logic.

Honey at 210 degrees is thin so let’s give it a 50.

Honey at room temp behaves like molasses so if there was a rating for a room temp it would be act like a 70.

You get it cold and it becomes even thicker.

[ninety1two40]

You guys are throwing numbers all over, what is the actual measurement unit for these viscosity numbers?

[Wayne64SS]

Ask Vlad, he’s grasping this REALLY well. :rofl :rofl

[Vovchandr]

@ninety1two40

You guys are throwing numbers all over, what is the actual measurement unit for these viscosity numbers?

Multiple, SAE and cSt are the common ones used and talked about here.

The picture above I posted will show both.

[jdaniels]

@Vovchandr

I understand that. Where is the miscommunication?

Again, I’ll bring the honey and see if I follow your logic.

Honey at 210 degrees is thin so let’s give it a 50.

Honey at room temp behaves like molasses so if there was a rating for a room temp it would be act like a 70.

You get it cold and it becomes even thicker.

I know what you’re saying. If we are talking actual viscosity measurements of the oil as you are – it’s obviously far different. They are just numbers assigned to an oil that tests like that at a given temp.

@ninety1two40

You guys are throwing numbers all over, what is the actual measurement unit for these viscosity numbers?

That’s exactly the issue. SAE ratings are just a number assigned to an oil that measures X viscosity @ 212* - it’s a fixed number that does not change. It’s a label.

[Vovchandr]

Let’s see if re-arranging the chart above using cSt and SAE will help any.

[bennyfizzle]

mother of god

[Murrdog9000]

:rofl