Let the debate continue

[Jake777]

If you feel so inclined check out this brief article and share your thoughts.

http://www.machinerylubrication.com/Read/518/motor-oils

So what do you think? Generally an exceptable premise?

 

[turtlevette]

I get the impression these guys are power plant and industrial experts. I'm taking that article with a grain of salt.

 

[Leo99]

I stopped reading at the 3rd paragraph with this silly statement:

Anyone accelerating slowly or driving at the speed limit to conserve energy is a danger to himself and other drivers who are in a much bigger hurry.

 

[tig1]

Just another thick vs thin thread.

 

[Jake777]

Ok. Fair enough forget it

 

[Shannow]

The stuff that they say about film thickness and viscosity is correct.

The stuff that they say about a thin oil offering less margin in an overheat is correct.

The stuff that they say about possibly needing a higher viscosity for certain activities that generate heat is correct.

The tone of the article is scaremongering.

 

[EA82]

Yeah more of the same stuff that's been covered here countlessly, and also stated clearly in most owners manuals.

 

[pbm]

The article is from 2003....a lot has changed since then.

 

[Shannow]

Originally Posted By: pbm
The article is from 2003....a lot has changed since then.


Some fundamentals are science fact, (like viscosity and MOFT) and can't change with time.

But I agree, what happens when parts touch is continuously changing.

 

[SandCastle]

The article makes a good point about how a 20F change in oil temperature changes the viscosity by the equivalent of one SAE grade.

I long thought the oil temperature tracked the coolant temperature (more or less), but as I learned with my new car (which has an oil temperature gauge) that is definitely not the case. On colder winter days the oil temperature barely reaches 170F after 13 miles of driving to work, even if the car has been parked overnight in an attached garage in which the ambient is above freezing. Even though the coolant temperature stabilizes after 5 miles, the oil temperature lags far behind. Thus I drive to work in the winter with oil that is way too thick for the entire trip. However, in the summer the oil temp reaches 190F rather quickly. So I think it makes sense to use 0W-20 oils in the winter and go up one grade in the summer to 5W-30. For engines needing more viscosity, use 0W-30 in winter and 5W-40 in summer.

 

[Panzerman]

Originally Posted By: pbm
The article is from 2003....a lot has changed since then.


Yeah, Ford is starting to recommend 5w30 oil in its engines again.

 

[Panzerman]

Your going to have rule followers that do whatever they are told by the manual believing somebody they never met is smarter than they are and your going have these "Common sense" people that actually add things together and experiment and find out the world really isn't flat after all. My Lincoln 4.6 gets "better fuel mileage with 10w30, is quieter. I had many cars start well with no trouble in well below 0 with 15w40 oil. Contrary to popular belief oil thicker than 5w30 doesn't not turn into a solid below 30 degrees.

 

[tig1]

Originally Posted By: SandCastle
The article makes a good point about how a 20F change in oil temperature changes the viscosity by the equivalent of one SAE grade.

I long thought the oil temperature tracked the coolant temperature (more or less), but as I learned with my new car (which has an oil temperature gauge) that is definitely not the case. On colder winter days the oil temperature barely reaches 170F after 13 miles of driving to work, even if the car has been parked overnight in an attached garage in which the ambient is above freezing. Even though the coolant temperature stabilizes after 5 miles, the oil temperature lags far behind. Thus I drive to work in the winter with oil that is way too thick for the entire trip. However, in the summer the oil temp reaches 190F rather quickly. So I think it makes sense to use 0W-20 oils in the winter and go up one grade in the summer to 5W-30. For engines needing more viscosity, use 0W-30 in winter and 5W-40 in summer.


That is so old school( visosity changes by the seasons) I can't believe we are talking about this today. I did that in the 60's and early 70s. With the quality of oils today, just use the wt the engine builders recommend and enjoy the long life of your engine.

 

[tig1]

Originally Posted By: Panzerman
Originally Posted By: pbm
The article is from 2003....a lot has changed since then.


Yeah, Ford is starting to recommend 5w30 oil in its engines again.


Yeh, in a large V8 designed for very heavy duty hauling.

 

[tig1]

Originally Posted By: Panzerman
Your going to have rule followers that do whatever they are told by the manual believing somebody they never met is smarter than they are and your going have these "Common sense" people that actually add things together and experiment and find out the world really isn't flat after all. My Lincoln 4.6 gets "better fuel mileage with 10w30, is quieter. I had many cars start well with no trouble in well below 0 with 15w40 oil. Contrary to popular belief oil thicker than 5w30 doesn't not turn into a solid below 30 degrees.


You forgot that around 80% of engine wear occurs on start. If you like thick oils and believe they flow faster in cold temps, then try 20-50 and really have that 4.6 spin over. By they way, I had engines have a difficult time starting in cold temps with 10-40.

 

[Shannow]

Originally Posted By: tig1
You forgot that around 80% of engine wear occurs on start. If you like thick oils and believe they flow faster in cold temps, then try 20-50 and really have that 4.6 spin over. By they way, I had engines have a difficult time starting in cold temps with 10-40.


You've mistaken the facts here tig1 (again, but I'll repeat again)

The wear occurs during warm-up, not "at start"...of course you don't get to warm-up without starting, but the wear is caused during warm-up, not the few seconds that it takes to get oil pressure.

The "flow" of thin oils (the 20, 30, 40) does nothing to reduce wear at start or during warmup.

The xW part of the oil's rating is referencing the pumpability and ability to feed the oil pick up at the extremes of the oils low temperature range...

A 0W does not reduce wear at freezing point, a 20 grade does not reduce startup wear...nor during warmup, when the actual wear is taking place.

An inappropriately chosen "W" grade (or an oil that has lost it's W rating in service) can cause massive damage quickly.

 

[tig1]

Originally Posted By: Shannow
Originally Posted By: tig1
You forgot that around 80% of engine wear occurs on start. If you like thick oils and believe they flow faster in cold temps, then try 20-50 and really have that 4.6 spin over. By they way, I had engines have a difficult time starting in cold temps with 10-40.


You've mistaken the facts here tig1 (again, but I'll repeat again)

The wear occurs during warm-up, not "at start"...of course you don't get to warm-up without starting, but the wear is caused during warm-up, not the few seconds that it takes to get oil pressure.

The "flow" of thin oils (the 20, 30, 40) does nothing to reduce wear at start or during warmup.

The xW part of the oil's rating is referencing the pumpability and ability to feed the oil pick up at the extremes of the oils low temperature range...

A 0W does not reduce wear at freezing point, a 20 grade does not reduce startup wear...nor during warmup, when the actual wear is taking place.

An inappropriately chosen "W" grade (or an oil that has lost it's W rating in service) can cause massive damage quickly.



So thicker oils on start(even though they flow slower) produces no more wear than thinner oils(0-20 or 0-30) do on cold starts?

 

[Shannow]

Firstly, flow doesn't provide lubrication (101 is wrong there).

On start-up, if the W grade of the oil is appropriate for the conditions, the galleries will be filled at the same time regardless.

So at my place, there would be no real difference between a 0W, 5W, 10W, or 15W anything at getting the oil galleries filled, and pressure to the system.

With the system primed, the thicker oils will have less oil flow to the bearings etc. and more through the relief, as the bearings draw oil off the pressurised galleries only what they need to replace their side leakage.

Less flow just means that the bearings need less oil, not that they aren't lubricated as well.

The wear occurs when the galleries are full, and the oil is flowing, and the engine isn't up to temperature...Industry standard Sequence IV the engine is running, the oil is flowing, just the temperatures are controlled to the point that the viscosity protection is dropping, but the additives aren't functional...that's where the wear takes place.

 

[Shannow]

edhacket provides a good summary in this thread.

https://bobistheoilguy.com/forums/ubbthreads.php/topics/2145915/1

Ignore the obvious comments from the usual peanut in the thread.

 

[B320i]

Originally Posted By: Shannow
Firstly, flow doesn't provide lubrication (101 is wrong there).

On start-up, if the W grade of the oil is appropriate for the conditions, the galleries will be filled at the same time regardless.

So at my place, there would be no real difference between a 0W, 5W, 10W, or 15W anything at getting the oil galleries filled, and pressure to the system.

With the system primed, the thicker oils will have less oil flow to the bearings etc. and more through the relief, as the bearings draw oil off the pressurised galleries only what they need to replace their side leakage.

Less flow just means that the bearings need less oil, not that they aren't lubricated as well.

The wear occurs when the galleries are full, and the oil is flowing, and the engine isn't up to temperature...Industry standard Sequence IV the engine is running, the oil is flowing, just the temperatures are controlled to the point that the viscosity protection is dropping, but the additives aren't functional...that's where the wear takes place.


I would understand it as more a combination of flow + pressure... When the oil cannot flow due to obstruction (i.e. bearings not needing oil, or oil too thick for the galleries) it creates pressure.

Naturally, I assume there is a balancing point where the oil pump itself is moving enough oil in terms of flow/quantity, but also enough in "reserve" so as to create some pressure.

If the pressure is very high at start and warmup and a large amount of oil is bypassing - is this really ideal as opposed to a thinner oil where less is bypassed?