Moly and roller lifters........skidding???

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Hello, I have a concern about excessive moly in oil (such as additives, or in Schaeffers oil, etc.) and it causing the needles in the roller bearing of a roller lifter to skid or slide rather than roll. Once a bearing slides and creates a flat spot it's a short life after that!! This has been talked about in a few forums, and I would like to hear some feedback from here. Some say it happens, others call it B.S.

Thanks, Brian
 
Blue I don't think you would have a problem with a product like Schaeffers or others who use the soluable moly in the additive package. I think where you might run in to trouble is with some of these after market moly additives that are not a soluable base.
 
If the surface is soooo slippery that the roller can not get enough grip to roll, then how in the world will it wear a flat spot into it? I previously worked as an engineer for Timken, and to my knowledge, they had never tested a lubricant that was so slippery that the rollers would rather skid than roll. This will happen in a poorly designed bearing, or one that is misaligned or used incorrectly...but it will happen in any oil.
 
I think he was implying that the insoluble moly would build up and form a "wedge" in front of the roller, causing it to "skid" instead of roll. Much the same way that a truck tire would build up a wedge of gravel while braking on a ravel road.
But I could be dead wrong on his inferences.
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The theory or myth is that the moly provides a surface so slippery that the needles will actually slide rather than roll. This results in flat spotting and destroying the bearing. There are many mixed opinions on this. This may be an occurence of incorrect alignment or incorrect spring pressure at the valves. This can be dated back to Harley Davidson blaming synthetic oils on the failure of their roller lifters.
 
There are different kinds of moly additives. Do a search of molys. There would be lots problems because moly is used in many oils now with zinc.and phos levels being low.
 
Quote:


Hello, I have a concern about excessive moly in oil (such as additives, or in Schaeffers oil, etc.) and it causing the needles in the roller bearing of a roller lifter to skid or slide rather than roll. Once a bearing slides and creates a flat spot it's a short life after that!! .... Some say it happens, others call it B.S.

Thanks, Brian





Well if you really think about it, it's counterintuitive. After all, you are saying the moly creates so much "slickness" that the cam can't make enough friction to grip the roller enough to make it turn...instead the roller stays in place and slides on te cam.

That would be an unbelievable reduction in friction. However, if you could believe that was possible, then how would it ALSO be possible in an environment of unbelievably low friction for the cam to somehow wear a flat-spot in the roller, when it can't even grip it long enough to turn it? This does not compute.

After all, if you think about it, the very second of the occurrence of enough friction between the cam and the roller to be able to wear a flat spot in it, then the roller bearing would just do its job and turn rather than stand still. But wait, how could the roller be rolling...when the moly supposedly makes the roller too slick to roll....but then...how could the roller be wearing if there's so little friction it won't even roll!?!? (and so on)

What you are describing seems virtually inconceivable to me. Others describe it as B.S.
 
jim 5 - as told by isky to my machinist
the rollers ride on the cam and turn well its the needles that spin in the same spots in reference to the centerline of the lifter body inside the roller body and dont themselve rotatate properly around the axle that caused the flattened needles on the bottom side only . not the roller itself . he did not know the cause and warantied the lifters in our case .it's just a therory that has not been proved. i would suspect the lack of zinc in the oil causing this and the molly letting it slide over the bad needles that got pounded like all the solid non roller cams that we have failed !
 
Porsche super engines in the 60s used roller bearings in the big end connecting rods and needles in the small end. The roller bearings and the needle bearing could under certain conditions fail. The reason just described by Isky was the cause. Bearing got pounded flat and went downhill quickly.
 
Well I have spoken to about 4 cam companies, and 3 Oil company tech reps. Each of them said to me (off the record) they have had issues with this very problem and advised me of only high quality mineral oils changed more often.
 
http://www.machinerylubrication.com/arti...s%20and%20Gears

How Age and Contamination Affect Rolling Bearings and Gears

how Si levels in Moly might cause failures


http://www.smokstak.com/forum/showthread.php?t=6446

As you know the moly works into the metal surfaces and provides enhanced lubrication when there is the potential for metal to metal contact. The reason moly is NOT reccomended for ball bearings is because the moly can build up on the race surfaces and reduce the bearing clearances enough to cause bearing failure. Some years back the Model A Ford club reccomended a moly grease for the rear axle ball bearings. There was a rash of axle bearing failures traced to this moly build up on the races. It is in fact an irregular build up of the moly and forms patches on the races and it had the same effect as dirt in the bearing. So don't use moly or any moly additive on any ball or roller bearing application. This includes transmissions also.


http://www.tundrasolutions.com/forums/engine-and-drivetrain/22022-why-not-use-moly-based-engine/

Check out the OEM bulletin from Cummins. It is the Cummins Engine Oil Recommendations, Bulletin No. 3810340-02 . Its probably best if you stopped by a Cummins Dealer and purchased this bulletin- about $2 or $3.
On page 7 it has a section on FRICTION MODIFIERS states:
"There is firm evidence that certain friction modifiers, molybdenum dithiophosphate for example, can in certain formulations result in cam follower pin failure at relatively low mileage"........
 
1sttruck.

With reagrds the machinery lub article. If one reads further down the quality of moly is directly proportional to wear. This is also studying moly dithiophosphate NOT moly dithiocarmate used in engine oils.

With regards to the second article referenced model a ford club. Moly does not build up. It creates 39 slippage plans as in adheres to metal. No more.

With regrds to the Cummins bulletin. Circa 1984. Again this bulletin is with regards to formulators that did not do their reasearch and were using dithiophosphate not dithiocarbamate.

I think Johnny said it very well.
"Blue I don't think you would have a problem with a product like Schaeffers or others who use the soluable moly in the additive package. I think where you might run in to trouble is with some of these after market moly additives that are not a soluable base."
While I can not speak for others. This has never been a problem with Schaeffers oil which is currently run in Nascar, Nhra, hooters, Arca and thousands of race tracks across the globe.
 
The moly used for decades was the dithiophosphate. Did Schaeffers use it ? If they did when did they quit using it ?

I'll guess that most use the dithiocarbamate, it's a common additive these days in well regarded oils, but the dithiophosphate still sems to be around.

The '39 planes' would apply to a layer of pure moly / MOS2, while worst case someone can dump some MOS2 powder into grease, stir it a bit, and slather it into some bearings.
 
Schaeffers has been formulating dithiocarbamate moly motor oil since 1969. With no issues..... And with retractions in 1983-4 from Cat and Cummings with regards to their blanket statements on "moly oils".

Any problems that occurred were with dithiophosphate in oils. Which brands I do not know, but not Schaeffers.
 
Well I heard that Redline have more Molly then anyother oils does anyone know if thats ture? Any Roller issues to speak of???? or what about with Amsoil?
 
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This may be an occurence of incorrect alignment or incorrect spring pressure at the valves.




Think you nailed it. I have only seen a handful of roller lifter failures. The needle failures were nearly always due to either floating the lifter or incorrect bore indexing. Roller lifters do not like to be floated becaue they can sustain major damage when they slam back on the lobe. In this respect flat lifters can take more abuse. I have always been a proponent of rev kits in roller apps, it can save parts.
 
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