Industrial thick versus thin debate

[AJB0009]

Nothing says BITOG quite like a good 'ole thick versus thin debate.
Here is a question that I run across on the Mobil Industrial forum recently and the official Mobil response.
Question posted:
As we know, optimal viscosity helps to form a lubricating film, keep machine components cool, seal the system and control oil consumption. Therefore, what will happen and possible condition to machine if we change ISO 150 to 220 of gear oil. Are there any significant effects on machine? But, EB only describe to use ISO 150.
Here is the response:
Hello,

In general, the use of higher viscosity oil will tend to run hotter due to more internal friction within the oil. As a rule of thumb, when operating above 60 deg. C, every 10 deg. C increase in temperature, the oxidation rate will double, thus will reduce the life time of the oil becomes half. The oil becomes more prone to oxidation. This also applies to gear box elastomers.

When there is no changing in gearbox design (speed/load), the gear box should remain running with ISO VG 150 oil.

Hope this helps


Best Regards,
Teguh Mawardhana
SAP Technology Support Engineer

 

[Dave9]

You should just stick to the manufacturer recommendations instead of posing half truths as if "as we know" changes that.

 

[XJRiver]

Video interview with a Chevron rep speaking about this infernal topic

Video: How lighter oil can cut construction equipment fuel costs

In this episode of The Dirt, a Chevron Lubricants expert explains how switching to lighter, thinner oil can raise construction equipment’s fuel economy.

www.equipmentworld.com

 

[AJB0009]

You should just stick to the manufacturer recommendations instead of posing half truths as if "as we know" changes that.

Just to be clear, I am not the one that posted the question on the forum. I was just on there today and saw it; so I thought that I would share it here. I believe that it came from another country.

 

[bullwinkle]

You should just stick to the manufacturer recommendations instead of posing half truths as if "as we know" changes that.

It sounded like that's what the Mobil rep said? That heavier than required oil would cause heat buildup & rapid oxidation? Unless I misread it somehow? It does seem to be a gear oil/gearbox question, not a motor oil question.

 

[Jetronic]

There's nothing new there. But so glad you highlighted "optimal viscosity". Now the question becomes, what is the optimal viscosity in the component concerned, and are you running it?

Industrial gearboxes tend to run a high and constant load, it's fairly easy to determine what the optimal viscosity is and what grade will get you there.

Cars run up and down hill, in town and on the freeway, summer and winter, and only very short bursts of full power unless towing. Temperature, RPM and viscosity are always changing. So how do you determine optimal viscosity and what grade will get you there?

the last line from the Mobil rep says it all: "When there is no changing in gearbox design (speed/load), the gear box should remain running with ISO VG 150 oil." In cars you have to go by useage case and accept that it won't be the same day to day, hour to hour

 

[kschachn]

Plus in an engine there’s little shearing action compared to a gearbox.

 

[dlundblad]

OPE will run hotter with a thicker oil too.

With something industrial, I’d go by the book 100%.

 

[wemay]

"Who cares, just use some of that GF-6 oil!"

-Scotty Kilmer

 

[MolaKule]

"...In general, the use of higher viscosity oil will tend to run hotter due to more internal friction within the oil. As a rule of thumb, when operating above 60 deg. C, every 10 deg. C increase in temperature, the oxidation rate will double, thus will reduce the life time of the oil becomes half. The oil becomes more prone to oxidation. This also applies to gear box elastomers.

When there is no changing in gearbox design (speed/load), the gear box should remain running with ISO VG 150 oil.

Hope this helps


Best Regards,
Teguh Mawardhana"
SAP Technology Support Engineer

The Tech Support Engineer is correct.