GREASES .. what is Fiber length

[BOBISTHEOILGUY]

Yes, it is a very interesting subject as it is an area that is very important but less looked upon when discussing lubrication in general.

George, the main thing I wanted to do was look at some of the technical #'s. Interesting enough, even though moly is an issue, reversability is also very important and what is bothersome is that many greases when heated up such as the lithium complex, will seperate not allowing the oil to mix back in thus seperate and lose it's ability to maintain proper lubrication. I know you stated you use the exact same grease without the moly, but question is, just how exact is the two in comparision to both tech data sheets.?

IMO, I'd be looking at other areas other than just the moly side of the grease, reversability being one of them as well as temp's and such. I'd very interested in seeing the tech sheets on the one with moly and the one that is working without moly so to compare in what differences you incurred by switching,as I suspect you'll see there has to be some variances between the two other than just the moly.

 

[radiometer]

If I might come in again on this: I just found an old container of Valvoline NLGI No. 2 Aluminum Complex grease. Much of the writing is difficult to impossible to read but one portion of yet clear print discussing automobile wheel bearings says "...for Ford Vehicles use Valvoline Special Moly EP". Again, I wonder if each blender of moly grease must know whether his will work with antifriction bearings or not. I'm beginning to see that some produce products that might not work well in this application whereas others (by their statements and my experience) perform well in antifriction applications. krholm

 

[GeorgeCLS]

Regarding the moly/non-moly. In one case, both greases are absolutely identical. You can go to the Mobil site and for heavy/construction mining greases, the PDS reflect is there and reflects: same thickener (Lithium complex), same base oil viscosities, same everything except of course the moly additized grease reflects higher LWI, Timken, etc. than the non-additized grease.
I keep going back to the aspect that there is Moly then there is Moly.. Apparently Schaeffer's, Primrose, etc. are using a different form/grade, whatever, of moly than other grease manufacturer's are using. I am getting the same, consistent, reply from other lube engineer's who I have talked with, with years experience (non-Schaefer/Primrose) and they all have the same horror stories with moly that I have had in failed NF and universal joint bearings when moly was used in those applications.
Again my only purpose here is learning, not grinding, as the moly obviously works in NF applications with the Schaeffer, Primrose, etc. formulations..
Continued.......

 

[BOBISTHEOILGUY]

Oh I understand George, Never took your comments/post as grinding. I'm just as interested in understanding why as well. From what my chemist was telling me, that it is not a special moly no more than any other grease moly. Said that it has not changed in many years.

give me the links to those tech data sheets if you would, be very interested in looking at them, not that I don't believe you, just maybe over looking something somewhere?

[ September 18, 2002, 09:37 AM: Message edited by: BOBISTHEOILGUY ]

 

[BOBISTHEOILGUY]

quote:

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Originally posted by TooSlick:
Ken,

The addition of moly-disulphide reduces the oxidation stability of the grease under extended high temp use. So the best product for these applications is "GLC". In terms of "best practices", you generally want to stick with an NLGI (national lubricating grease institute) #2 product for high temp wheel bearings, due to viscosity considerations. (I'm sure you know all this stuff, but not everyones an engineer.)

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It's a shame that the moly in your grease causes oxidation problems in comparison to the non moly.

Ours is the oposite. Heat being one of the biggest problems that incurs oxidation and moly being a FM/AW, causing the reduction of heat, actually helps keep oxidation problems from happening as soon. Of course there is other factors involved where oxidation is concerned but quite frankly, moly is not so much the cause as it can be an asset to keeping oxidation levels down.

 

[TooSlick]

Bob,

You might find it interesting to compare the anti-wear performance of these two greases under standardized, ASTM testing. These are directly from the respective spec sheets:

"Moly Pure" Synthetic Grease/Amsoil HD moly grease

Oxidation Stability ASTM D-942
(psi loss @ 100 hrs)

2% loss/0% loss (3% @ 300 hrs)

Timken Load Test (ASTM D-2509)

60 lb load/70 lb load

Four Ball EP kgf (ASTM D-2596)

Weld Point-- 315 kg/400 kg
Load Wear Index-- 45/68 (higher is better)

Four Ball Wear Test (ASTM D-2266) Scar Diameter

.68 mm/.40 mm (smaller is better)

 

[widman]

Unfortunately the SKF electronic handbook does not allow cut and paste, (but it is downloadable). It states that "for heavily loaded bearings eg: rolling mill bearings, it has been recommended to use EP additives....... The utmost care should be taken........to make sure the EP additives are not of the damaging type....... assurances should be made by the lubricant manufacturer....... Solid additives... eg Molybdenun disulfide partical size should be 0.2 um

 

[widman]

sorry, hit the wrong button and it won't let me edit.... "particles smallera or larger will separate"

 

[SteveD2]

quote:

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Originally posted by TooSlick:
Georgeseq,

Amsoil makes their synthetic (lithium complex) grease with and without moly ...they specifically recommend using their multipurpose grease that does NOT contain moly for high temp/high speed bearing applications. Their HD moly grease is recommended for high load, low speed, low temp applications where you need a solid film EP additive like moly ....

Ted

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Amsoil recommends their moly-fortified grease for anti-friction bearings including wheel bearings and u-joints, "The correct consistency grade of AMSOIL GH EP Moly Greases are recommended for use in heavy and light duty applications found in manufacturing plants, automotive applications, agricultural equipment and construction equipment. These include, but are not limited to, roller bearings, ..., thrust bearings, wheel bearings, chassis lubrication, universal joints, ball joints, tie-rod ends,...."

Amsoil also says, "NLGI #2 (GHD) is the preferred choice for medium to high ambient temperatures,...and is the primary choice for wheel bearings."
http://www.amsoil.com/products/ghd.html

Ken

 

[TooSlick]

Ken,

The addition of moly-disulphide reduces the oxidation stability of the grease under extended high temp use. So the best product for these applications is "GLC". In terms of "best practices", you generally want to stick with an NLGI (national lubricating grease institute) #2 product for high temp wheel bearings, due to viscosity considerations. (I'm sure you know all this stuff, but not everyones an engineer.)

 

[BOBISTHEOILGUY]

TED, That shows what you are saying to be true, but unfortunatly, we both know that you are looking at one little aspect of that grease with this test and it does not take into account how the moly additive will effect the heat in actual situations so, on the bench, I'll go with ya on that, but in true applications, the moly will provide a lower coeffiecent to friction therefore relieveing some of the base oil strain from the heat produced otherwise, therefore giving you a difference in oxidational resistance compared to the tested bench numbers and greases without such.

This is simular to the motor oil concept, lower the heat with the FM's, you don't have to use a full synth to maintain extended drains because the FM/s are reducing the heat and putting less strain on the base oil.

This is common where everyone thinks that full synth's is needed in all engines for extended drains when in fact we have proven many times over that a good blend will provide near and sometimes better results at extended drains since we use the moly in the oil to reduce the heat and scuffing putting less stress on the base oil.

So point is, lower the heat factor from friction, less strain on the oil therefore, less oxidation occurance.

Widman, You may have something there.. The size of the moly particles could possibly be a concern with some of these other moly greases that are incurring this frosted bearing problem maybe? Moly is refined in many different sizes and levels so, could this be a clue to the problem differences that some have experienced?

BTW, you can post the link on that download on here if you would. It's sales pages I don't allow, technical data pertaining to the subject is not a problem.