Suzuki Burgman USA Forum banner

1 - 20 of 73 Posts

·
Registered
Joined
·
3,122 Posts
Discussion Starter #1
What the numbers mean

So, the multigrade label doesn’t actually tell you what your oil thickness is right now, but only the sort of range to expect at a specific temp (100C) when the oil is new.

So let’s say your engine oil is at 150 deg C.
A 10w40 oil would be in the 2.9 CP band for high shear viscocity
A 15w40 oil would be in the 3.7 CP band for high shear viscocity

Don’t worry about what that means at this stage, just notice they both end in 40 but are behaving differently at high temperature


So why use the multigrade label in the first place?
Well it is a good shorthand for users that don’t care about the details and you just want to pick up a carton that fits your machine - and because people are used to it.

If you want to know the actual viscocity you would use a different system, I tend to use cst out of habit but there are others. This is the viscocity right now at whatever temp it happens to be at.

At 100C a 40 weight oil is around 14 cst, so your - - w40 oil will try to be somewhere in the band around that when it hits the same temp.

The cold number is a bit more complicated because it uses different temperatures for different grades and slightly different target figures because the interest is on how low the temp can go before the oil becomes too hard to move around.
The reference are cold cranking viscocity and cold pumping viscocity
10w is 7000 CP at -25 (max cranking) and 60,000 CP at -30 (max pumping)

05w is 6600 CP at -30 (max cranking) and 60,00 CP at -35 (max pumping)

CP (centipoise) is a measure of “dynamic viscocity” - think 2 plates sliding over each other.
Cst (centistoke)is a measure of “kinematic viscocity” - which is more like pour.
 

·
Registered
Joined
·
903 Posts
People give WAAAAYYYY too much thought about motor oil, because there are so many options.

Vehicle manufactures specify what is needed. Buy any brand/weight that fills that need... done.


You rarely see these same discussions about gas/coolant/wiper-fluid, even greases. Yet on every auto/bike forum there are thousands of posts about oil.


I've lived my life like Earl... motor oil is motor oil.


..... that don’t care about the details and you just want to pick up a carton that fits your machine......
That's me!
 

·
I'm Retired
Joined
·
9,363 Posts
...
So if you live somewhere hot do you need to move to a 15w40 or higher?
Well think about other people’s engines, do they ever see those temps already? Yes, every time they start up they pass through that same temperature.
Mostly it would just wate fuel and increase mechanical stress.
First, thanks for a well written and clearly understandable explanation of oil viscosities. It was very well done.

Those last lines reminded me of an earlier post I made. Many people think the outside temperature has an effect on oil. It definitely does on the lower extremes, like in the cold north. I don't think it matters nearly as much in the warmer climates. My BMW is the hottest engine I think I've experienced. I've noticed that whether I'm in temps in the 30s, or in the 90s or even over 100F, the temp gauge still reads three bars. I've been in stop and go traffic in temps in the high 90s and the temp gauge still read three bars. The only thing that seems to change, is how fast and often the radiator fan kicks in. And even in the 20s, the fan will kick in quickly.

My point is the operating temperature of the engine is quite hot. The cooling system using the radiator, is designed to maintain the engine temperature at the point where it works as the engineers designed it to be. The idea that I need higher viscosity oil in hotter temperatures probably came about from air cooled engines and oils that thinned out too much in those days. (Just guessing.)

Chris
 
  • Like
Reactions: Anon and Dave_J

·
Registered
Joined
·
3,122 Posts
Discussion Starter #6
First, thanks...
Those last lines reminded me of an earlier post I made. Many people think the outside temperature has an effect on oil. It definitely does on the lower extremes, like in the cold north. I don't think it matters nearly as much in the warmer climates. My BMW is the hottest engine I think I've experienced.
Thanks.

It’s hard to answer the question without getting technical but I’ll give it a go.

In a well designed, pressure cooled, modern engine, more or less yes, the operating temperature inside the engine is going to be the same most of the time.

There are caveats related to the oil you are using and the type of engine.

(First, temp gauges usually show coolant temp which isn’t the same as oil temp and some oil gauges are in the sump not up in the hotter oil).
I once had the job of working out why a car engine was short lived in a newer car design compared to a previous one with the exact same engine. The problem was the cooling air flow around the sump was poor in hot weather so the oil couldn’t cool the internals properly. There can be a ceiling to what each vehicle can deal with.

If they got the engine right there are a few things that can add up together to work against you.

Oil has lots of different additives doing different jobs, one is calcium - used as a detergent.
Calcium reduces the heat transfer ability of the oil, one of the reasons I’m not a fan of high detergent additive packages being put in motorcycles.

Hot cities are a bit of a nightmare because there is very little airflow to carry the heat away when you are stood still

Crud in the engine and coolant quality/age are obviously in the mix. Diesel engines cool in a slightly different way to petrol engines.
 

·
I'm Retired
Joined
·
9,363 Posts
...There are caveats related to the oil you are using and the type of engine...
:eek Now you have me concerned! ;) I started using Rotella T6 based on the statements made years ago by the "experts" on this forum. I trusted them completely! I hope they haven't steered me wrong. :D

FWIW, I used one of those infra-red thermometers yesterday on the engine and what was surprising to me was the oil sump was pretty cool. In fact, it was one of the coolest areas of the engine and frame.

Chris
 

·
Administrator
Joined
·
18,201 Posts
What the numbers mean

......
At 100C a 40 weight oil is around 14 cst, so your - - w40 oil will try to be somewhere in the band around that when it hits the same temp.

The cold number is a bit more complicated because it uses different temperatures for different grades and slightly different target figures because the interest is on how low the temp can go before the oil becomes too hard to move around.
The reference are cold cranking viscocity and cold pumping viscocity
10w is 7000 CP at -25 (max cranking) and 60,000 CP at -30 (max pumping)

05w is 6600 CP at -30 (max cranking) and 60,000 CP at -35 (max pumping).........
Blue, Thank you for showing us some stat's. Kind of what I have thought most of my life.

MikeyMarine, No this information will not get you a date at the bar late at night.

But looking at all the numbers, the jump from a 5Wxx to a 10Wxx is only about a little jump. With our cooling system keeping the temps in about the same range during normal operation I still stand firm that 5W40 T6 will protect our engines just as well as a 10W40.

In the case of my first Burgman 650 and its loud Transmission noise issues. I had done a few Engine/Transmission oil changes and always had 10 quarts of 10W40 JASO MA oil on the engine oil shelf in my fireproof wall locker.
But I did not know that my son had done an oil change on his car that took a 0W20 oil but he had 3/4 of a quart left over from a gallon jug. So he took one of my empty 10W40 bottles and filled it up, put a Sharpie line across the label and put it on the oil shelf.
So I went to the locker and got out enough to do my engine oil change and thought, time to do the trans too so I grabbed one more bottle, one with a Sharpie line on the label. Within 250 miles it started to squeel and when I pulled the drain plug and a GRAY "Water Thick" oil poured out. Lots of aluminum in that oil. So I assumed that the 0W20 sheared down real fast in those 4 gears of the transmission and I lost the lube quality that a 10W40 would have been.
 

·
Registered
Joined
·
657 Posts
Most people will know roughly what the 2 multigrade oil numbers mean (ie 10w40)
There is a “cold” number and a “hot” number telling you what to expect from your brand new oil.

By misunderstanding what these numbers mean it is easy to assume an 0w40 and a 15w40 are going to be exactly the same at high temperature - so Its OK to ignore the first number. But that isn’t accurate. I’ll start simple and explain this towards the end.

From the beginning:
The first number has a “W”, which stands for “winter”. This is because the multigrade system is an antiquated system from an earlier era, it’s a bit quaint but it is easy to grasp if you just want to pick something up off the shelf and don’t design oil or engines.How multigrade oil works...

A single grade 10w oil is thin and easy on the starter in the cold, but too thin when it heats up.
A single grade 40 weight oil is thicker and protects hot engines, but too thick when it is cold.
So we have multigrade, it behaves like a 10w at one temperature, but like a 40 at a higher temp.

How?
For oils that started in the ground it is all down to magic polymers called “viscocity index improvers”.
There is a whole bunch of these but that would be several pages - basically they scrunch up small when they are cold and then open up like flower petals as they get warmer.



So when they get warmer they block the oil from moving around as much so it behaves as though it has thickened up.
Note that the oil hasn’t thickened up, it is an apparent change, the oil is itself hasn’t changed, only stuff in the oil.

Good and bad
It’s a great trick but there are problems. The improvers are soft and they get torn up.

First there is “shear” the soft polymers get stretched and broken up easily compared to oil. So your 10w40 can become 10w30 frighteningly quickly. This called shearing out of grade.
The more polymers the more shear (oil out of the ground with a wide grade has atheism most polymers)

There is also “temporary shear” which is different. This is when polymers nest together like saucers and don’t give the protection you want or they get squished out of shape by high pressure. This is invisible to some testing that you see in manufacturer blurb because the molecules immediately bounce back and pretend nothing happened.



There is an upside that can be claimed to this behaviour - the pic above represents a piston ring. The polymer on the left is not under pressure so it is behaving normally. The one on the right is squished out of shape, something that isn’t always wanted but here it is doing a good job of blocking that gap and preventing the oil getting past the ring and being wasted.
The polymer isn’t oil but it traps oil within it so there is still some lubrication there.

Genuine synthetic oils are slightly different because they are already multigrade so fewer additives to shear down but it escapes the engine more easily.

So what has cold got to do with hot?
Multigrade doesn’t jump from 10w to 40 in one step and then stop jumping like an on/off switch. It a continuous line with 2 fixed points.

The second number in a multigrade gives an idea of the apparent viscocity at 100 deg C
So, yes, everything with a 40 on the end will try to be in the 40 weight range at 100 deg C. (The actual value is around 14 cst)

But your engine oil isn’t going to be at 100 deg C and the oils are starting off to that target from different places according to there first number -
They approach the same point at 100 deg but then they cross over because they overshoot at different angles.

I’ve never measured my Burgman oil temp but on other vehicles I’ve seen oil temps of under 50 deg at the sump sump and above 200 deg. in hotter areas.
Some oil somewhere is likely to be at 100, but most of it isn’t. The difference isn’t vast but there is one.

Last bit
Being a grade out isn’t going to immediately kill a Burgman engine and isn’t something to get overexcited about - but you can lose out in fuel economy, power and speed of ageing if by jumping to the wrong conclusions.

So if you live somewhere hot do you need to move to a 15w40 or higher?
Well think about other people’s engines, do they ever see those temps already? Yes, every time they start up they pass through that same temperature.
Mostly it would just wate fuel and increase mechanical stress.

There are, indeed, far too many useless posts about motor oil on these sites. But this one is TRULY USEFUL, so thanks! It isn't going to change a thing that I do, but I like understanding a little more about the products I'm using.
 
  • Like
Reactions: Anon

·
Registered
Joined
·
3,122 Posts
Discussion Starter #10 (Edited)
:eek ...Rotella...BMW
BMW are good at flow and stuff, they put a lot of time into it and have excellent facilities/talent.

Regarding oil - I wasn’t thinking of Rotella, it isn’t particularly high in calcium. From memory it does have some calcium but mostly magnesium as detergent/dispersant, probably magnesium sulfonates. Main additive is zinc (again going from memory, they change it all the time).

Detergents are weird critters at the molecular level, I might add something about those.
 

·
Registered
Joined
·
3,122 Posts
Discussion Starter #11
10w is 7000 CP at -25 (max cranking) and 60,000 CP at -30 (max pumping)

05w is 6600 CP at -30 (max cranking) and 60,00 CP at -35 (max pumping)
But looking at all the numbers, the jump from a 5Wxx to a 10Wxx is only about a little jump. With our cooling system keeping the temps in about the same range during normal operation I still stand firm that 5W40 T6 will protect our engines just as well as a 10W40.
No, You are reading that wrong, partly my fault, I missed the “deg C” thinking it was clear.

The numbers you highlighted are values at -25, -30, -35 deg. C not at operating temperature.
 

·
Registered
Joined
·
3,122 Posts
Discussion Starter #12
There are, indeed, far too many useless posts about motor oil on these sites. But this one is TRULY USEFUL, so thanks! It isn't going to change a thing that I do, but I like understanding a little more about the products I'm using.
Thank you for the kind words, I’m glad it did it’s job.
 

·
I'm Retired
Joined
·
9,363 Posts
whut he say?
This is the difference between engineering types and insurance salesmen. The engineering types want to know why something works and how it does it. Maybe even fix it a bit. The insurance guys just want the car to work so they can talk to you. There's a place in the world for both. And a need for both.

There was a study done by the Paradise Garage years ago on synthetic oils that I thought was interesting. They had a Camaro LS1 and put in Mobil 1. Then ran it without any oil changes for 18,000 miles. At each oil change interval, they sent the oil out for analysis and only topped off the oil as needed. They did a similar test with Amsoil and came out with comparable numbers. I thought it was interesting because they chronicled what was done over the time it took to put on those miles. If you're interested in what I thought was fascinating reading, check out that link and the related links to the left of the web page.

One caveat to what you'll read there. At the time of the study, Mobil 1 was a "true" synthetic with a PAO base. Now, you can't find out what it uses for a base stock, only that it is synthetic.

Chris
 

·
Registered
Joined
·
3,122 Posts
Discussion Starter #14
During development of oil/engine combinations the last stage is destructive testing.
Some engines are put through hard cycles until they die and some are left with the throttle wide open until they burst, no oil changes.
(Some of the engineers break down crying and need counselling at seeing this, no names but I’m looking at you QM)

With the genuine synthetics I’ve seen tests abandoned because time ran out, the engine would not die before the end of the project.
It is astonishing stuff
 

·
Administrator
Joined
·
18,201 Posts
OK, "WITH IN" our operating temperatures with maybe a +/- of 5 Degrees C on both ends, is there really any BIG differences between a 5W40 and a 10W40 that will put the 5W40 oils "OUTSIDE" the protection level required for a Burgman 400/Burgman650's 10W40?

On average most members will ride as low as 40F (4C) and high of 115F (+46C), none that I know will ride at -35C (-31F). My lowest has been 12F (-11C) and highest has been 110F (43C).

I am not a molecular engineer. But my BUTT ENGINEERING Degree has proven time and again that a 5W40 works within the operating temperatures range of my WATER COOLED bikes.
 

·
Registered
Joined
·
3,122 Posts
Discussion Starter #16
OK, "WITH IN" our operating temperatures with maybe a +/- of 5 Degrees C on both ends, is there really any BIG differences between a 5W40 and a 10W40 that will put the 5W40 oils "OUTSIDE" the protection level required for a Burgman 400/Burgman650's 10W40?
Not when new, no. as I said at the beginning, it’s not going to make a disastrous difference
Being a grade out isn’t going to immediately kill a Burgman engine and isn’t something to get overexcited about
But if you select an oil that shears out of grade quickly, yes you can be left with less than the minimum protection.
You would probably see a fuel economy drop if you went the other way to a 15w40 though.

One thing I missed out which kind of links to that.
These grades are not spot figures, they are “bands” or “ranges”
So to be a **w40 the oil has to between 12.5 cst and 16.3 cst when it is at 100C.
(So when I say “around 14 cst I mean in that range)

Some oils might fall at the high or low extreme so there is already a vagueness built into the description. It isn’t a pin point accurate system.
 

·
Premium Member
Joined
·
8,033 Posts
Blue, l

MikeyMarine, No this information will not get you a date at the bar late at night.
I dunno Dave, sometimes the right lube is really important :devil
 

·
Registered
Joined
·
3,122 Posts
Discussion Starter #19
Thank you.
I tried to keep it simple and jargon free but there has to be some.
I’m not an oil guy, I’m a dynamics guy. The real oil guys explode my head on a regular basis so you can imagine how freaky they are.

I just have to know enough to nod in the right places.
 

·
Registered
Joined
·
3,122 Posts
Discussion Starter #20
Detergents got mentioned so I’ll have a go at that.

Obviously these aren’t the same as the stuff you wash the pots with, it’s more likely to be something like calcium or magnesium.

It’s actually a 2 part operation, detergent and despersant.
The molecules used have one end that really likes oil and another that likes sludge and crud and I can already hear @mikeyMarine laughing - yes, I know what that looks like.



So the molecules surround the muck and stop it attaching to other muck. They keep it floating around to be drained or caught in the filter.

In some case the push and pull as oil moves around helps these surrounding molecules and it breaks up the crud into smaller pieces that get surrounded and isolated. That stops it settling to the bottom of the sump and forming a sludge.

The principal is pretty straightforward but the detail gets crazy complicated after that, and chemistry isn’t my thing.

Picture nicked from Amsoil
 
1 - 20 of 73 Posts
Top