shind3

Absolutely wrong.
Oil Viscosity Explained

1st number is tested at 40C while the 2nd number is tested at 100C. What about 40 degrees Celsius reminds you of Winter exactly? 40C = 104F. Where do you live where initial engine start oil temperature of 104F is considered to be a Winter condition? On Planet Earth, that is certainly not described as Winter. In the same way, that listing the test value at 100C doesn't warrant an S after it for Summer.

What you are conflating is the assumed extrapolation of having a 2nd data point in addition to the 1st at 100C. Listing behavior at 40C as well as at 100C let's the consumer predict how the behavior will be at even colder temps. That does not mean the 1st number is the rating for the oil in Winter.

I notice your facetious use of the word 'precious' to describe 10W60. Your bias shows as loudly as your ignorance. Besides that, I probably agree with you since the larger the range between the viscosity at 40 and 100C, the less shear stable an oil tends to be.

Yes, it was able to produce such a high HP/L because the engine was able to reliably rev almost 2000RPM higher than most other engines around at the time due to having a lubrication system capable of doing so. Of course, you also need suitable camshafts to keep adequate airflow at those RPMs for it to make sense to rev that high. Most engines that rev to 7000RPM for example, start experiencing a power drop-off at 6500RPM. And since VTEC lets you run two completely different cam profiles, they were able to spec the high cam to whatever they wanted regardless of EPA emissions regulations since that cam would never be invoked during typical EPA testing. So the S2000 engine was special because of VTEC, a big ass oil pump, and race spec cams. None of this makes the engine 'tight' as claimed by many on the internet. And since VTEC was introduced a decade prio, it wouldn't be considered 'modern' either.

Good catch. Your name is irrelevant to this discussion. It was my mistake to feed a troll in the first place since you had no substance of consequential value to contribute. I should have known better. This will be my last response to riff-raff such as yourself.

Do you have any details on the 'recommended' new bearing specs?

SpitfireS

Dear Shind3,
You really, yes really (!) need to read up on oil.
You're mixing and matching ideas and figures to produce your own reality, like the popular "alternative facts".

Lets start with your explanation of 5W-20 oil.
I have picked 5W in this case.
The first number ISN'T measured at 40C.
It's clear to see in the link YOU posted.
5W means the oil has a maximum cold cranking or maximum cold pumping viscosity, in the case of 5W, measured at -30C and -35C respectively.
Those are facts, clearly defined by SAE J300.
You are wrong with your explanation.
Period.

Do thin oils, like a xW-20, compared to xW-60, protect worse?
No.
It's about (and you did mention it) the HTHS.
And about the HTHS you need in an engine.
HTHS is also a viscosity (cP), measured at 150C.
When oil is sucked into a journal bearing it heats up very quickly.
And heat means it gets thinner.
If it gets too thin the oil film will break under the high load in that journal bearing and parts touch eachother.
This is bad.
The HTHS number shows how thin the oil is at 150C.
Is thicker by default better? No.
If your engine is designed around a HTHS of 2cP for example and your oil can produce 2,8 at 150C, an oil with a HTHS of 4cp will not protect better.
You have to keep an eye on shear stability though, as oil straight out of a bottle may have a good HTHS but after 10000km may not.
So we use a 30 weight oil, with HTHS values of about 3 to have some safety over time.

Is using a 60 weight oil bad?
Well... it could be.
As I mentioned, your oil pump has a bypass.
That's because the oil pump is a positve displacement pump, which means if the outlet is blocked it goes BOOM.
The bypass is a safety valve, a springloaded piston.
Piston area x oil pressure = force, if that force exceeds the designed limit the valve will open and dump oil back into the oil pan.
The more engine rpm = the more oil pump rpm = more oil pressure.
The thicker your oil, the higher the oil pressure produced by the oil pump.
Combine the 2 and you will see a thicker oil makes the bypass open at a lower engine (=pump) rpm.
So a 60 weight oil makes your bypass open at a lower rpm, that is not good.
There have been posts on s2ki from a German S2k owner saying he damaged the engine using Castrol Racing (!) 10W-60 in his S2000 and driving fast (high rpm) on the Autobahn.
Yes, just the one (or 2 posts) but still.
The F2x does not need a thick oil.

I've seen more than one post on BITOG (and they KNOW about oil) showing 10W-60 oils sheared down pretty quickly.
Quickly means within 1500 miles or so: they are not very shear stable at all.
That data is from a while ago though.
Still I would never ever recommend a xW-60 oil for any S2000.

The F20 can do the RPM based on this:
A very stiff engine block.
A roller rocker (= low friction) design.
Yes, the high lift cams next to the normal cams (VTEC system)
A well designed intake.
An OEM high flow cat, a metal foil cat to be exact.
And last but not least the low friction FRM cilinder liners.
They allow the piston speed at 9000 rpm.
I don't think the oil pump has too much to do with it.
It is a high output pump to supply the oil jets with enough oil at 9000 rpm to keep the pistons cool.

shind3

Can you please quote the exact sentences from that which support your point?

SpitfireS

Do your own research.

We were talking xW-20 oil, like it shows on the bottle.
The 1st number, preceded by the "W", as YOU put it, IS NOT tested at 40C.

You may have, at some point, seen an oil data sheet.
And on those data sheets the manufacturer actually DOES show the viscosity at 40C.
It gives a bit of info about the composition of the oil, when compared to the viscosity at 100C.
That data is not published on the oil bottle you buy.
And you, as I think, have been mixing and matching numbers and ideas.
And you made a mistake.

shind3

Can you please present proof of this statement?

There are so many falsehoods in your posts that I really don't know where to begin. So I'm going to respond to it one by one. Starting with this one.

Please explain how ASTM D445 is not used to describe the viscosity characteristics of the oil at 40C and 100C. Also, if you disagree, please be sure to let Mobil 1 know of your groundbreaking discoveries... LOL
Mobil 1™ 0W-40

SpitfireS

Let's start with your first post in this thread, post #16.
What is your interpretation of what a huge percent of the polulation thinks is the first number *succeeded* by a "W", as seen on oil bottles?
Let's use the 5W-20 again?
Please, think about it for a moment, before you answer.
I'm going to guess you're going to say "5"
So by your explanation quoted above, a 5W-20 oil, has a 5 cSt viscosity at 40C?
No it does not.
If YOU can find evidence to prove me wrong here, please post it.
A 5W30 oil TDS I found about an hour ago, replying in another post, shows those oils has a viscosity of around 42 cSt at 40C
And that oil isn't labelled 42W-20, now is it?

At some point you're going to have to admit you were wrong.
Or you keep believing your self made alternative facts.

Have fun.


edit: I changed the original word preceded into *succeeded* to avoid this being used as an excuse.
IMO it doesn't change the discussion.
And I eddited several typo's.
Oh well...

Chuck S

30-grade oil has a CS of 10 at 100°C but the number does not appear on the bottle or can anywhere. (Numbers rounded for convenience.)

10cs seems to be the number that engine clearances have been designed around "forever." Think of 30-grade as universal. Too thick, though, to flow well enough to lubricate at colder temperatures where it has a thickness of about 100 at 75°F/25°F. Even 0-grade oil is 40cs at that temperature. Still too thick but better flowing. Engines warm up fast. Cylinder head temperatures exceed 100°F within a minute or two even in the winter. An oil with a CS of 40 will drop to 10cs faster than a 100cs oil.

To obtain a CS of 10 at lower temperatures requires a multi-grade oil of some sort. So a 0W-30 oil would be 40cs at normal starting temperatures but the required 10cs at 212°F.

Back in olden days it was necessary to put a different grade oil in cars in the winter and summer. A car may have required 10-grade oil in the winter. 10W is a logical way of expressing that even if technically not what W means. Or does it? The automobile world if full of obsolete technical expressions. Anyone know what Load Range C means on tires? Or "Ply rating"? All hold-overs from the distant past. <---- don't answer those questions, this is about oil.

As long as the oil has the right CS and is flowing the engine will have good lubrication. It appears engines are now being engineered to be fine at 6cs which means they can be as low as 20-grade.

CS at operating temperature is paramount and thermostatically controlled water cooled engines seldom exceed 100°C in normal operating conditions. Water cooled race cars are going to run hotter but not dramatically if properly designed. (Discussion of optimal engine temperature for efficient operation and power is a separate topic.) Air cooled engines lack thermostats and can get hotter so have different oil requirements. 20W-50 is common (because the engines run hotter). CS at starting temperature is also important.

Fortunately good synthetic multi-grades do this all automatically for us if we stick to grades with the proper CS.

-- Chuck

SpitfireS

Be carefull, Chuck S, to claim water cooled engines don't get hotter than 100C.
That is true-ish for the coolant, the engine as a unit, but not for oil.
Engine oil does get hotter, even under normal operating conditions, in places like at the top journal of a connecting rod (small end IIRC) and also in the crank journals.
Don't forget that normal for an F20 is anything between idle and 9000 rpm ;-)
The oil that's sprayed underneath the pistons also gets well above 100C.
In both positions the oil gets this hot for a (very) short time.
But it could be long enough to get thin enough to break the oil film.
They measure the HTHS at 150C for a reason.

EricLovato

why don't you explain to all of us what you're so upset about? You're coming off very angry, defensive, and rude to others on this board for no reason at all. We all have our own opinions on oil and viscosities and none of us own an oil company so quit pretending like you're better than everyone else on here. Just have fun, Be humble to others, and LISTEN to what others have to say.......you JUST might learn something!

shind3

This is still wrong! Thinner oils are NOT better at holding up the needed film strength. The thinner the oil is the LESS film strength it has. Now thinner isn't necessarily bad depending on the engine's design but your statement above is just plain wrong. While you are correct in saying that if the oil is too thick it can prematurely open the bypass but its effect is a decrease in heat extraction from the bearing surfaces and that is not the same as the FILM STRENGTH. There is an appreciable difference between these two concepts.

Also, I said the xW-yz nomenclature is a REPRESENTATION of the Kinematic Viscosity. Never said 5W equals 5cSt... They are simply ranges. For example, a 30 weight oil means its kinematic viscosity is between 9.3 and 12.5 cSt. 40 weight is from 12.5 to 16.3 cSt.

Maybe this chart explains it better. Look at the 2 scales to the left. One for Kinematic Viscosity at 40C and another at 100C. Now look at the 3rd column for "SAE Crankcase".


Anyway, I will concede that the 1st number isn't as straight forward as I said earlier. And it also looks like they are calling the thinner grades 'Winter'. Basically anything thinner than a 20 weight (15,10,5,0) is considered 'Winter' oil which is I assume due to reasons that Chuck S mentioned. Prior to the advent of multi-grade oils, people had to run oil thinner than a 20 weight in the winter.

Perhaps this chart explains it best. It basically shows an oil is given a rating based on where it intersects the two lines for oils made from purely the base oil (1st number) and the VI improved oil (2nd number), respectively. It also looks like having these 2 data points of the kinematic viscosity at 40C and 100C you can compare the performance of the oil at even colder temperatures. Thankfully all oil manufactures list these 2 values online in their datasheets such as Mobil 1™ 0W-40


It is also important to consider the difference in Kinematic and Dynamic (Absolute) Viscosity and the different units they use.