0W-20 in a BMW M-60

[OVERKILL]

Originally Posted By: kschachn
Well, not a surprise from the physics of oil, but from a marketing standpoint. I think it is easy to think that any oil marketed as a 0W-something is superior for low temperatures but that's not how the grading system works. Clearly from this example this 0W-40 is far thicker at low temperatures than their 0W-30 product. And a lot more than their 5W-30 as well.



Not so fast. In order to qualify as a 0w-xx an oil has to be below the maximum limits for CCS and MRV at -35C and -40C respectively. M1 0w-40 is thinner at BOTH of these temperatures than their 5w-30, otherwise their 5w-30 would be a 0w-30

This became somewhat relevant to me the other morning when I started my truck with a 5w-30 in the pan (PU 5w-30) @ -30C instead of the AFE 0w-30 I had in there previously, which would have been a solid 1,000cP lighter AT LEAST, than the PU 5w-30, which was 4,000cP.

 

[bobbydavro]

Fresh oil is pretty irrelevant anyway considering the oil in your sump is used. Something like ROBO performance is probably more interesting( but much harder to get for the consumer)

The ROBO (or IIIGA) give used oil MRV performance.

 

[fpracha]

Originally Posted By: OVERKILL
Not so fast. In order to qualify as a 0w-xx an oil has to be below the maximum limits for CCS and MRV at -35C and -40C respectively. M1 0w-40 is thinner at BOTH of these temperatures than their 5w-30, otherwise their 5w-30 would be a 0w-30

The 0w-30 should be lighter than 0w-40 at extreme cold temperature within its pour point range... then how are the MRV and CCS of 0w-40 really same as for 0w-30 grades ?

 

[fpracha]

Originally Posted By: CATERHAM

That really shouldn't come as a surprise. For the same chemistry, the heavier the oil (higher the grade or higher the HTHSV to be more precise) the worse it's extreme cold performance.
The other thing to keep in mind is the parabolic nature of oil at extremely cold temp's. Even for 0W oils the viscosity change with temperature as you approach -40 degrees is dramatic. Just one degree can raise or lower an oil's viscosity as much as 20% while at -20C it could be as little as 1%.

Yes operational viscosity is representing the resistance of oil at actual conditions. The opposite is also true... or it is not :
At high temperatures the 0w-20 oil will be worse at protecting than the 0w/5w-30 and high rpms should be avoided ?

 

[LotI]

Originally Posted By: fpracha
Originally Posted By: OVERKILL
Not so fast. In order to qualify as a 0w-xx an oil has to be below the maximum limits for CCS and MRV at -35C and -40C respectively. M1 0w-40 is thinner at BOTH of these temperatures than their 5w-30, otherwise their 5w-30 would be a 0w-30

The 0w-30 should be lighter than 0w-40 at extreme cold temperature within its pour point range... then how are the MRV and CCS of 0w-40 really same as for 0w-30 grades ?

"Should be"...we don't know unless tested. They just have to under the spec to be a 0w-xx grade.

 

[OVERKILL]

Originally Posted By: fpracha
Originally Posted By: OVERKILL
Not so fast. In order to qualify as a 0w-xx an oil has to be below the maximum limits for CCS and MRV at -35C and -40C respectively. M1 0w-40 is thinner at BOTH of these temperatures than their 5w-30, otherwise their 5w-30 would be a 0w-30

The 0w-30 should be lighter than 0w-40 at extreme cold temperature within its pour point range... then how are the MRV and CCS of 0w-40 really same as for 0w-30 grades ?


The 0w-30 is thinner. We know it is because we have the MRV for both it and the 0w-40, LOL

However the post I was responding to specifically mentioned a 5w-30, which, at -35C, would be heavier than the 0w-40. It has to be because it carries the 5w-xx designation, not the 0w-xx designation, which it would be required to carry if it was below than the 6,200cP limit for CCS at -35C.

 

[CATERHAM]

Originally Posted By: fpracha
Originally Posted By: CATERHAM

That really shouldn't come as a surprise. For the same chemistry, the heavier the oil (higher the grade or higher the HTHSV to be more precise) the worse it's extreme cold performance.
The other thing to keep in mind is the parabolic nature of oil at extremely cold temp's. Even for 0W oils the viscosity change with temperature as you approach -40 degrees is dramatic. Just one degree can raise or lower an oil's viscosity as much as 20% while at -20C it could be as little as 1%.

Yes operational viscosity is representing the resistance of oil at actual conditions. The opposite is also true... or it is not :
At high temperatures the 0w-20 oil will be worse at protecting than the 0w/5w-30 and high rpms should be avoided ?

Anyone who has spent any time operating a vehicle in extremely cold ambient temp's knows the problem is not just getting the car started but also keeping as much heat in the oil as possible.
That's why even for a car like the BMW M3 that's spec'd for 10W-60 you'll be far better off running a light 0W-20 because it will be a constant struggle to get even a 0W-20 hot enough to reach it's ideal operating temperature range of say 80C-90C for that car.
If it's -30C out and you did manage to get your oil temp's up to 80C after a long drive and then stopped 5-10 minutes for gas, when you restarted the engine the oil temp's will have likely already cooled off to 60C or so which with a 0W-20 still results in an operational viscosity that is way thicker than optimum.

Operating in subfreezing temp's high oil temp's are not an issue.
If you have oil gauges to monitor things it's it's actually impossible to run an oil that is too light. If you don't that's the only reason to run a 0W-30 vs a 0W-20.

 

[bobbydavro]

Er what? That is far too simplistic, oil works in a lot more than just the sump of the engine and hence localised pressures and temperatures are very different.

When the oil is cold it's even more dependant on hydrodynamic lubrication as the anti wear isn't working. One of the worst things you can do is go to a thinner oil in this situation. Going to a 0W-20 from a 10W-60 would be madness in an M3 engine, especially when BMW specify the oil. Why do you think a 20 weight is going to help?

Fwiw specific heat capacity of oil goes up with viscosity

I see in your signature you think blending two oils some how makes an oil better than anything in the market. What's your thought behind this?

 

[kschachn]

Who are you talking to? I think from the content that it is CATERHAM but the reply was to me.

In any case, are you making the claim that using a thinner oil when cold is the worst thing you can do?

Originally Posted By: bobbydavro
Er what? That is far too simplistic, oil works in a lot more than just the sump of the engine and hence localised pressures and temperatures are very different.

When the oil is cold it's even more dependant on hydrodynamic lubrication as the anti wear isn't working. One of the worst things you can do is go to a thinner oil in this situation. Going to a 0W-20 from a 10W-60 would be madness in an M3 engine, especially when BMW specify the oil. Why do you think a 20 weight is going to help?

Fwiw specific heat capacity of oil goes up with viscosity

I see in your signature you think blending two oils some how makes an oil better than anything in the market. What's your thought behind this?

 

[bobbydavro]

Caterham, sorry I forgot to quote.

I'm saying going thinner than a 10W-60 wouldn't be a good idea in something like an M3. As to why, I pointed out some of the fuel and water dilution issues in an earlier post, plus the bearings in this engine need a high film thickness. The 10W-60 is about 5.2 HTHS. The same applies to the M60 regarding ignoring OEM recommendations and trying to correlate film thickness to viscosity

Some 30 grades are thicker ( have higher base oil viscosity than other 40 grades).

My point still stands regarding film thickness being more critical. Some industry wear tests become less severe when you run them cooler as the film thickness increases and negates the fact the ZDDP isn't working

As long as the oil gets to the journal bearings within a second or two and the low pressure light goes there is no real need to read into the viscosity grade too much, certainly not enought to ignore the 3.5cP min HTHS BMW specify in this engine. Just because it's colder doesn't mean you can drop viscosity

 

[kschachn]

Yeah, I know about the problems needs with the M3.

Where do you see that the M60 in my 530i requires a 3.5cP min HTHS? I've been through the manual before and I haven't seen that. It only says SG I think. I did post the requirements earlier in this thread.

Originally Posted By: bobbydavro
Caterham, sorry I forgot to quote.

I'm saying going thinner than a 10W-60 wouldn't be a good idea in something like an M3. As to why, I pointed out some of the fuel and water dilution issues in an earlier post, plus the bearings in this engine need a high film thickness. The 10W-60 is about 5.2 HTHS. The same applies to the M60 regarding ignoring OEM recommendations and trying to correlate film thickness to viscosity

Some 30 grades are thicker ( have higher base oil viscosity than other 40 grades).

My point still stands regarding film thickness being more critical. Some industry wear tests become less severe when you run them cooler as the film thickness increases and negates the fact the ZDDP isn't working

As long as the oil gets to the journal bearings within a second or two and the low pressure light goes there is no real need to read into the viscosity grade too much, certainly not enought to ignore the 3.5cP min HTHS BMW specify in this engine. Just because it's colder doesn't mean you can drop viscosity

 

[edyvw]

Originally Posted By: kschachn
Yeah, I know about the problems needs with the M3.

Where do you see that the M60 in my 530i requires a 3.5cP min HTHS? I've been through the manual before and I haven't seen that. It only says SG I think. I did post the requirements earlier in this thread.

Originally Posted By: bobbydavro
Caterham, sorry I forgot to quote.

I'm saying going thinner than a 10W-60 wouldn't be a good idea in something like an M3. As to why, I pointed out some of the fuel and water dilution issues in an earlier post, plus the bearings in this engine need a high film thickness. The 10W-60 is about 5.2 HTHS. The same applies to the M60 regarding ignoring OEM recommendations and trying to correlate film thickness to viscosity

Some 30 grades are thicker ( have higher base oil viscosity than other 40 grades).

My point still stands regarding film thickness being more critical. Some industry wear tests become less severe when you run them cooler as the film thickness increases and negates the fact the ZDDP isn't working

As long as the oil gets to the journal bearings within a second or two and the low pressure light goes there is no real need to read into the viscosity grade too much, certainly not enought to ignore the 3.5cP min HTHS BMW specify in this engine. Just because it's colder doesn't mean you can drop viscosity


As far as I know, at that time oil of the day in Europe for that engine was 5W40, which menas HTHS greater then 3.5.

 

[CATERHAM]

Originally Posted By: bobbydavro

I'm saying going thinner than a 10W-60 wouldn't be a good idea in something like an M3. As to why, I pointed out some of the fuel and water dilution issues in an earlier post, plus the bearings in this engine need a high film thickness. The 10W-60 is about 5.2 HTHS. The same applies to the M60 regarding ignoring OEM recommendations and trying to correlate film thickness to viscosity

Some 30 grades are thicker ( have higher base oil viscosity than other 40 grades).

My point still stands regarding film thickness being more critical. Some industry wear tests become less severe when you run them cooler as the film thickness increases and negates the fact the ZDDP isn't working

As long as the oil gets to the journal bearings within a second or two and the low pressure light goes there is no real need to read into the viscosity grade too much, certainly not enought to ignore the 3.5cP min HTHS BMW specify in this engine. Just because it's colder doesn't mean you can drop viscosity

And you're 100% wrong.
Because it's cold is EXACTLY why you can run a lighter oil and that includes oil with a HTHSV rating well below 3.5cP.
It's all about operational viscosity and the viscosity in every part of an engine correlates to the sump oil temp's.
The reason the European manufacturers have moved away from specifying 20 grade and light 30 grade oils for low ambient temperature conditions (they all used to) is because synthetic oils made it possible to specify a heavy 30 grade oil (min' 3.5cP HTHSV) and heavier 0W-XX oils for year round use.
This made it impossible for some clueless owner who still had a 20 grade oil in the sump from the winter to run his BMW or Porsche flat out on the autobahn in the summer with resulting increased engine wear or worse.

The fact remains that you can still very much benefit from running a 0W-20 (HTHSV 2.6cP) oil in sub-freezing conditions in any high performance car during the winter months.
As I've pointed out before in this thread, your engine can't tell the difference between a 0W/5W-30 (HTHSVv 3.5cP) at 100C oil temp's and a 0W-20 (HTHSV 2.6cP) at 85C. They both nominally have the same operational viscosities. The big difference is on start-up and during warm-up where your engine will very much appreciate having the much lighter 0W-20 oil in the sump.

 

[edyvw]

Originally Posted By: CATERHAM
Originally Posted By: bobbydavro

I'm saying going thinner than a 10W-60 wouldn't be a good idea in something like an M3. As to why, I pointed out some of the fuel and water dilution issues in an earlier post, plus the bearings in this engine need a high film thickness. The 10W-60 is about 5.2 HTHS. The same applies to the M60 regarding ignoring OEM recommendations and trying to correlate film thickness to viscosity

Some 30 grades are thicker ( have higher base oil viscosity than other 40 grades).

My point still stands regarding film thickness being more critical. Some industry wear tests become less severe when you run them cooler as the film thickness increases and negates the fact the ZDDP isn't working

As long as the oil gets to the journal bearings within a second or two and the low pressure light goes there is no real need to read into the viscosity grade too much, certainly not enought to ignore the 3.5cP min HTHS BMW specify in this engine. Just because it's colder doesn't mean you can drop viscosity

And you're 100% wrong.
Because it's cold is EXACTLY why you can run a lighter oil and that includes oil with a HTHSV rating well below 3.5cP.
It's all about operational viscosity and the viscosity in every part of an engine correlates to the sump oil temp's.
The reason the European manufacturers have moved away from specifying 20 grade and light 30 grade oils for low ambient temperature conditions (they all used to) is because synthetic oils made it possible to specify a heavy 30 grade oil (min' 3.5cP HTHSV) and heavier 0W-XX oils for year round use.
This made it impossible for some clueless owner who still had a 20 grade oil in the sump from the winter to run his BMW or Porsche flat out on the autobahn in the summer with resulting increased engine wear or worse.

The fact remains that you can still very much benefit from running a 0W-20 (HTHSV 2.6cP) oil in sub-freezing conditions in any high performance car during the winter months.
As I've pointed out before in this thread, your engine can't tell the difference between a 0W/5W-30 (HTHSVv 3.5cP) at 100C oil temp's and a 0W-20 (HTHSV 2.6cP) at 85C. They both nominally have the same operational viscosities. The big difference is on start-up and during warm-up where your engine will very much appreciate having the much lighter 0W-20 oil in the sump.

And I agree with this 100%.
However, exactly beacause of ignorance of driver, I would stick to thicker oil. No one drives just within campus, everyone takes longer trip and then things get different.

 

[CATERHAM]

Even longer trips in the winter won't allow the oil temp's to approach anywhere near the same maximum oil temp's you can see in the summer.
The point is, if you're into motor oil and you want to more closely optimize the viscosity of the oil you use it can be done.
The safety margins we're dealing with are much larger than most realize.

 

[Clevy]

Originally Posted By: CATERHAM
Originally Posted By: bobbydavro

I'm saying going thinner than a 10W-60 wouldn't be a good idea in something like an M3. As to why, I pointed out some of the fuel and water dilution issues in an earlier post, plus the bearings in this engine need a high film thickness. The 10W-60 is about 5.2 HTHS. The same applies to the M60 regarding ignoring OEM recommendations and trying to correlate film thickness to viscosity

Some 30 grades are thicker ( have higher base oil viscosity than other 40 grades).

My point still stands regarding film thickness being more critical. Some industry wear tests become less severe when you run them cooler as the film thickness increases and negates the fact the ZDDP isn't working

As long as the oil gets to the journal bearings within a second or two and the low pressure light goes there is no real need to read into the viscosity grade too much, certainly not enought to ignore the 3.5cP min HTHS BMW specify in this engine. Just because it's colder doesn't mean you can drop viscosity

And you're 100% wrong.
Because it's cold is EXACTLY why you can run a lighter oil and that includes oil with a HTHSV rating well below 3.5cP.
It's all about operational viscosity and the viscosity in every part of an engine correlates to the sump oil temp's.
The reason the European manufacturers have moved away from specifying 20 grade and light 30 grade oils for low ambient temperature conditions (they all used to) is because synthetic oils made it possible to specify a heavy 30 grade oil (min' 3.5cP HTHSV) and heavier 0W-XX oils for year round use.
This made it impossible for some clueless owner who still had a 20 grade oil in the sump from the winter to run his BMW or Porsche flat out on the autobahn in the summer with resulting increased engine wear or worse.

The fact remains that you can still very much benefit from running a 0W-20 (HTHSV 2.6cP) oil in sub-freezing conditions in any high performance car during the winter months.
As I've pointed out before in this thread, your engine can't tell the difference between a 0W/5W-30 (HTHSVv 3.5cP) at 100C oil temp's and a 0W-20 (HTHSV 2.6cP) at 85C. They both nominally have the same operational viscosities. The big difference is on start-up and during warm-up where your engine will very much appreciate having the much lighter 0W-20 oil in the sump.



That does make sense. If the oil is cooler it is thicker,so low oil temps equals a thicker film of oil.
I was analyzing you post trying to play devils advocate and I must admit I got nothing.
My Harley for example. The oil cooler cools the oil so well while in motion I don't use a 20w-50,I use a 15w-40 hdeo.
While moving slowly I've got head cooling fans that cool the heads and jugs. Great system and allows me to use cheap hdeo without any fear and the fact that hdeo's tend to be nearly shearproof I am unconcerned about viscosity loss at temp.
My bike speaks to me,you just gotta learn its language. Noisy top end and oil loss means the oil has sheared,so change it etc.

 

[edyvw]

Originally Posted By: CATERHAM
Even longer trips in the winter won't allow the oil temp's to approach anywhere near the same maximum oil temp's you can see in the summer.
The point is, if you're into motor oil and you want to more closely optimize the viscosity of the oil you use it can be done.
The safety margins we're dealing with are much larger than most realize.

Are you sure about this? I would not be that confident in that since I had car with oil temp gauge, and managed to get it up to normaln temp after 10 miles while ambiant temp was -10c.

 

[nleksan]

HOLD ON A SECOND...


Did you do a motor swap?
I ask because an E39 530i has an M54B30, and the E60 mostly has an N52B30. The M6x series of motors are the 4.0, 4.4, 4.8L V8's as seen in the 540i, 740i, X5's, and so forth.
They are very, very different engines.


As far as putting 0w20 in an S54 (E46 M3/Z3M/Z4M), that's a guaranteed way to pound your journal bearings into oblivion. The only oil I use outside of the TWS 10w60 (the oil is so often reformulated, and it's done so as to best meet the needs of the current M engines, without TOO much change for the older ones, but still...), is RL 5-10W50. It gives me better track temps, but otherwise has bbeen a perfect substitute and I saw no out of the norm wear when changing bearings to Bimmerworld 50mm WPC-treated ones.

The 10w60 is actually perfectly fine in winter, I have noticed only the slightest increase in cranking time when it's below freezing, but no noticeable increase in the time it takes to get to temp (going by a real gauge, not the cluster temp Guage).

 

[bobbydavro]

Originally Posted By: kschachn
Yeah, I know about the problems needs with the M3.

Where do you see that the M60 in my 530i requires a 3.5cP min HTHS? I've been through the manual before and I haven't seen that. It only says SG I think. I did post the requirements earlier in this thread.

BMW only reccomend 3.5cP HTHS in the M62, i assume the engine is similar? Unfortunatley the M60 isnt on the BMW list I have.

 

[bobbydavro]

Originally Posted By: CATERHAM
And you're 100% wrong.
Because it's cold is EXACTLY why you can run a lighter oil and that includes oil with a HTHSV rating well below 3.5cP.
It's all about operational viscosity and the viscosity in every part of an engine correlates to the sump oil temp's.
The reason the European manufacturers have moved away from specifying 20 grade and light 30 grade oils for low ambient temperature conditions (they all used to) is because synthetic oils made it possible to specify a heavy 30 grade oil (min' 3.5cP HTHSV) and heavier 0W-XX oils for year round use.
This made it impossible for some clueless owner who still had a 20 grade oil in the sump from the winter to run his BMW or Porsche flat out on the autobahn in the summer with resulting increased engine wear or worse.

The fact remains that you can still very much benefit from running a 0W-20 (HTHSV 2.6cP) oil in sub-freezing conditions in any high performance car during the winter months.
As I've pointed out before in this thread, your engine can't tell the difference between a 0W/5W-30 (HTHSVv 3.5cP) at 100C oil temp's and a 0W-20 (HTHSV 2.6cP) at 85C. They both nominally have the same operational viscosities. The big difference is on start-up and during warm-up where your engine will very much appreciate having the much lighter 0W-20 oil in the sump.


Odd then as every OEM i speak to has more concerns with fuel diluton affecting film thickness than the impact of temperature on viscosity.

'your engine can't tell the difference between a 0W/5W-30 (HTHSVv 3.5cP) at 100C oil temp's and a 0W-20 (HTHSV 2.6cP) at 85C. They both nominally have the same operational viscosities.'

You speak only of Kv100, what about the many other factors, like BOV, HTHS at that temp, additive chemistry activation temperatures, oil film thickness etc etc.
As you know HTHS isnt just temperature, its also a measure of 10^7 shear rate, this is what your bearing sees irrelevant of sump and this is what matters.

From experience i know BOV is one of the critical parameters in a wear test, whether it be cold like the IVA or hot like a IIIG or TU3 (or VW RNT). This is all about the oils ability to form films to provide hydrodynamic protection. A 5W-20 BOV is typically around 4.3cSt. A 5W-40 will be >5cSt, 10W-60 is even higher. Here we dont car for the effect of VM on viscosity in a tube related to what the oil in sump is doing.

What we care for is the viscosity of the base oil, plus some addtive non newtonian thickening effects and the shear performance of the particular VM.

Anyway I digress, in terms of the OP. I see no benefit of going lighter, as once the engine has oil pressure there is ZERO advantage going for a lighter grade in terms of oil proection

Many 0W-40s will outperform 5W-20s anyway as they base oil offers both high BOV thus protection AND better cold pumpability (the technology of additives in European oils also tend to provide better used oil pumpability performance)