I’m taking a shit at a friends right now but someone please move this SHIT to epic:rofl
Vovchandr, what you are failing to keep in mind is what happens to ANY automotive-viscosity-oil at operating temperature REGARDLESS of it’s rating.
You change your oil. Just shut it off, hot summer say. Or Winter day. As long as the thing is running right and you just drove it highway stop and go, whatever so the gauge is right between H and C…it pours out almost like water. Sounds like that as the stream gets thin, almost drained out. I don’t care if it’s 10W with 10% kerosene as the manual for my almost-74-year-old vehicle calls for, or the 60% Lucas oil stabilizer 40% 20W-50 I run in my '87 Crown Prick because of one bad (loose, too big of gap) bearing.
The transmission in that '38 Buick has “600W Oil” in it, as sold by Early Ford Reproductions on 158 in Altamont. (This stuff is safe with bronze bushings found in that tranny and other “yellow metals”) I don’t know about that number, but it’s worse than Lucas. In the garage at about 50 degrees, it pours like silly putty. I’ve drained that transmission after a long drive on a hot summer day. Comes out like changing your oil.
At 160 degrees or thereabout, any oil is going to thin out like that. The task that chemical engineers have is to make sure that it doesn’t get as thin as say water or worse still. THEN the gap in your bearings won’t be filled, the journal will “rattle around” inside say the rod cap and big end to put it in extreme language, and eventually it would knock if enough wear happens.
In the dead of winter, it can’t be too thick that it won’t move and/or won’t “fit” in the gap between the journal and rod cap and big end. Again, extreme language, but thick enough fluids will take obscenely long to enter a microscopic gap and then leave it dry for too long.
Chemically we can make oils that lessen the effects of the environment on them (temperature). Read those last two things you quoted. The language is messing with you. It’s the same thing. Thinner oil when cold…compared to the “status quo”, an oil that’s bipolar and turns into water in the summer and molasses in the winter.
Back in the day of my Buick, you ran 10W with 10% kero “below -10F”, 10W at -10F to +10F, and 20W above that. Now…every engine has one oil viscosity stamped into your plastic oil cap. On my mom’s '02 ExploDer, “5W-20”. That ONE OIL is what you dump in, year round, no matter what. Could one argue with some specs and testing data that this is NOT adequate? Sure, but according to Ford’s testing, that oil is good year-round.
That’s the whole point, and technically you should follow your manufacturer’s specified oil rating, because they know the width of their bearing gaps and exactly what the thickness of the oil needs to be to correctly fill that gap. They then test and find out which multi-vis oil assumes those properties at the ambient temperatures that engine is going to see. Other variables like the oil passages’ sizes and the volume/pressure of the oil pump play a part and when you change THOSE for a performance/drag car setup it’s another can of worms opened up…why show off a dog jumping through a hoop like it’s an impressive feat? Anything will go through a hoop if you throw it hard enough.
Vlad, the “Strong Jellies” award of the month goes to you for being the PJB of motor oil:haha
:rofl
I’m going to get to the bottom of this tomorrow.
Rainmanpaul - I agree whole heartedly with everything except where you say wording is messing with me. Especially after that article that oil doesn’t behave like regular fluids do and thicken with temperature drop (right or not, who knows it’s the fact that it’s there)
For the same fluid (oil, honey whatever) two rating are given to it by SAE after temperature testing. First rating is given oil saying it’s thin when cold and fluid when warm due to second rating.
Like I said, I’m going to look into this more tomorrow.
Id be afraid to drink with a panda because it might eat me. Fuck, it would probably do that sober too though.
Do you agree that a 5W/SAE 5 motor oil is thicker at 0 degrees than a SAE 30 at 210 degrees? If so, what are we arguing about? If not, you’re wrong.
Why would I agree with that?
The thicker (higher viscosity) of an oil, the slower it will flow.
The lower the number the thinner the oil is. If it’s just one number on the bottle (30, “straight 30” it’s only been tested at one temp (210) and never tested at a lower temp.
Lets go even to room temperature. A straight 50 oil vs straight 10 oil, which would you say is thicker?
SAE 50 is thicker than SAE 10 at any given temp.
But you’re trying to compare them AT THE SAME TEMPERATURE!!!
Again, what’s thicker, an SAE 5 at zero degrees, or an SAE 30 at 210 degrees?
It’s 100 percent, without a doubt SAE 5.
You don’t understand how multigrade oils are rated.
I dont understand how a “thin, near water like” viscosity of 5 AT ANY TEMPERATURE, can be considered “thicker” than a honey type rating of 30 AT ANY TEMPERATURE by the same scale.
Scale doesn’t care what the temperature is. If it goes through the tube slow, it gets a high number, if it goes through the tube fast, it gets a low number.
A 5 went through the tube faster than 30, regardless of what temperature the fluid was set to before going through. That is exactly why one became a 5 and the other the 30. If they both go through the tube at the same rate, even with DIFFERENT temperatures, they would get the same number of viscosity.
Do you agree with that?
No, I don’t.
An SAE 5 will go thru an orifice (tube) at zero degrees SLOWER than an SAE 30 will flow thru the same orifice at 210 degrees.
And if you want proof, put a quart of 5W30 outside overnight, to simulate it in your oil pan. Time how long it takes to pour out. This will simulate how fast a SAE 5/5W pours at cold temps, right? Right.
Do the same test after boiling the quart of oil for an hour. Because of the properties of a multigrade oil, the oil is an SAE 30 at the time of the aforementioned test.
I’ll bet you 1000 dollars right now that the boiled oil, which is an SAE 30, pours faster than the SAE 5 did at cold temps.
5W30-SAE 5@zero degrees, SAE 30@210 degrees.
So if it goes through slower it’s thick and therefore should have a high SAE number.
Aka, again
The thicker (higher viscosity) of an oil, the slower it will flow.
I agree that in the real world oil thickens up when it gets colder, but the SAE rating gives it a low number as if it thins instead of thickens, against it’s own rules.
no no no no no totally wrong
You keep trying to compare the “W” number to the non W number, when there is simply no relation.
Sure, a 10W is thicker than a 5W (at zero degrees), but neither are as thin at zero degrees as an SAE 30 is at 210 degrees…
beating…dead…horse…
Ok BINGO. I haven’t trudged through all of the documentation quoted here but if that truly IS what they are saying…now that is bad language, and not at all what is happening with these oils. It’s a “gimmick” in that what you are buying isn’t somehow “5” weight oil AND “30” weight oil, or just exclusively one or the other.
I dont have time tonight but I am going to read that entire long article. It looks very informative…and one section points exactly to this “language” issue as I’m referring it. I think you even said something to the effect. I am getting a bit confused myself.
I think the takeaway from all of this…consult your manufacturer. Or an engine builder with experience if you’re doing something radically custom. Because clearly, as stated, the “number” and I say that in quotes because it’s looking really aribtrary and meaningless at this point…the number you see on the bottle does not come from any actual metrology involved with the testing of oils. It’s marketing, and it’s supposed to eliminate the need to know any of this. As the writer says "if designing an engine was easy, we’d all be doing it.
Not that you should remain willfully ignorant, but to get the job done, just go by what the automaker says to use in it.:crackup
I do also see the writer’s point about working backwards from hot running engine —> cold dead engine, oil cooling down and thickening not heating up and thinning. Design and testing looks at the engine in it’s, well, useful and most heavily needed and used state to know what it requires for lubrication. And that’s at operating temperature, running, producing heat. Sure all that wear comes at startup, but far MORE wear would occur if things were not right for 90% of the time that the engine is running, which is under load driving around, at operating temperature, on a long hour or more trip at higher speeds. At least in this sprawled country, most people don’t make the proverbial short trip that is bad for your car because it leaves condensation around, etc…
Show me a clause where it says that viscosity ratings for fluids only work for fluids at the same temperature otherwise the numbers are irrelevant.
Viscosity test doesn’t care what temperature the fluid is at. It just measures how fast it goes through the tube.
Where are you getting the information that the viscosity numbers are incomparable if the fluids are at different temps? That makes no sense.
This honestly feels like talking to PJB about getting a better job.
A 5W30 oil is a multigrade oil that CHANGES VISCOSITY WITH TEMPERATURE.
IT’S A DIFFERENT VISCOSITY AT ZERO DEGREES THEN IT IS AT 210 DEGREES.
IT’S A SAE 5 AT ZERO DEGREES. IT’S AN SAE 30 AT 210 DEGREES.
AN SAE 5 OIL AT ZERO DEGREES IS THICKER THAN AN SAE 30 AT 210 DEGREES.
Go get a quart of SAE 30 and a quart of 5W30. They will flow the same at 210 degrees, but the 5W30 will flow much better at zero degrees than the SAE 30 at zero degrees. Why? BECAUSE IT’S A MULTIGRADE OIL THAT CHANGES VISCOSITY WITH TEMPERATURE.
We should all read this before bed. It will put any of us to sleep.
That’s all great an all, but you’re forgetting the fact that a fluid with a viscosity of 30 AT THE TEMPERATURE IT GOT 30 at, has to be THICKER than a fluid with a viscosity of 5 AT THE TEMPERATURE IT GOT 5 at.
In other words if you’re pouring two 5w30’s next to each other, one being cooled to 32f other being at 210f, 30 ACCORDING TO SAE “higher number is thicker” should be pouring THICKER.
We both know it won’t.
WHICH IS THE POINT.
SAE NUMBERS DON’T FOLLOW THEIR OWN RATING.
This was the point from the first post :facepalm
I’m not forgetting anything, you cannot comprehend the information that is being presented to you.
Calling in the backup…
sits back and waits for the jury to deliver the verdict
Keep in mind, like any forum, not everyone there is an oil expert. Just hoping to get the attention of a few of them.