Originally Posted By: demarpaint
Interesting link, I wonder what the increase in Tin was from, still the report looked great.
Molybdenum Disulfide?
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There are other UOA that included Lubro-Moly MoS2, and I don't think there was any change or increase in the tin wear numbers. I don't even know what parts or components contain tin. It might have been just a glitch with the test equipment.
Yes, those Mobil 5w40 results were all pretty good.... the one with MoS2 was just a little better than all the others.
I think wrist pins are the source of Tin wear.
Main and rod Bearings have some Tin the in the alloy
Kestas
Staff member
Tin is found mainly electroplated on the finished surfaces of the journal bearings and pistons to aid in break-in.
Is there not still a thin layer of bronze under the babbitt coating on the crank and rod bearings?
Kestas
Staff member
Unless the technology has changed in recent times, the typical crank and rod bearing is made of pure copper powder layered on a plain steel backing. After sintering the copper powder, the voids in the copper are then infiltrated with lead, and the whole piece is electroplated with tin. There's no bronze in the unit.
There are higher-tech versions of this, but I've personally only seen them in seating mechanism applications.
aluminum is slowly replacing the lead/copper in plain bearings but steel/copper/lead is still the most popular from what I have read.
Kestas
Staff member
There's a big push to eliminate lead completely in automotive manufacture. Though aluminum is more environmentally friendly, it can gall in journal bearing applications.
Oils that contain Moly, have another additive blended in to protect the copper and other metals and so on etc. The disulphide part, where its the sulphur component that reacts with these parts. I think this also contributes to some of its benefits. Those like myself which every now and then add it as an additive may not have this protection.
Boosting any of the additives that raise the 'Sulphated Ash' level of the oil will have the same effect. Many people on here love Zinc, will push for more and more of it, people add it to their oils and it doesnt get scrutinised as much as Moly does. Too much Zinc is also bad for the engine.
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Years ago I used a product called Moly-slip which I think was molybdenum disulfide. After a few years the car was getting kinda tired and the oil pressure was dropping. I stopped using it since the car wasn't going to last much longer anyway. The oil pressure came back up and it ran better than ever. I later wondered if I was just pouring in a can of sludge.
My understanding is that the moly that comes already in oil isn't the same. Just because it says moly doesn't mean it's good.
Here are some previous posts about moly from MolaKule:
1. Indeed, this is an old report, comes up occasionlly, and has been discussed at least three times before. To compare soluble moly to the snake oil additives is ludicrous.
The fact is, a specific and early compound of moly, a class of molybdenum phosphordithioates, was "suspected" as being the cause of some corrosion. There was never a proven correlation.
Interestingly, those same molybdenum phosphordithioates have been used successfully in hydraulic oils without any problems or suspected corrosion problems.
Today's modern molybdenum dithiocarbamates, have never been the center of controversy or suspected corrosion.
In addition, the comment about the copper deactivator is also out of date and no longer correct.
Source: http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1180354&page=all
2. Please read this post and look at the various additives for each application or spectrum of applications:
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=530321#Post530321
There are many chemistries for friction modification, anti-wear, and Exreme pressure.
Moly is but one of them. In low concentrations, it acts as another friction (reduction) modification additive, in medium concentrations it acts as a friction modifier and anti-wear, at high concentrations it acts as mainly as an EP agent. There is nothing majic about it, it works, just like ZDDP.
Source: http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1156893
3. NOTE THE QUOTE BELOW IS NOW ALMOST FIVE YEARS OLD:
Tests have shown that engine oils can tolerate up to 750-800 ppm of moly dithiocarbamate before serious additive interactions takes place. So thats about 0.08% weight/weight.
And much depends on the OTHER additives present.
I would highly recommend you send in your mix for a VOA to Terry dyson before you run this stuff and then do UOA's every 1,000 miles.
Source: http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=149348
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Quote:
Years ago I used a product called Moly-slip which I think was molybdenum disulfide. After a few years the car was getting kinda tired and the oil pressure was dropping. I stopped using it since the car wasn't going to last much longer anyway. The oil pressure came back up and it ran better than ever. I later wondered if I was just pouring in a can of sludge.
I realize this has been somewhat beat to death, but I can't seem to find the answers I'm looking for. After scouring hours of posts and books, I still don't feel I'm any closer to answering these questions:
How well does molybdenum bond or 'mate' to different surfaces? Specifically, is there some indication that moly bonds (or adheres) to aluminum better or worse, than say, iron?
With many engines having aluminum blocks vs. iron blocks, I'm somewhat interested in this.
As I understand products such ad Lubro Moly's Anti-Friction additive, it has MoS2 and the sulfur should 'burn away' as the moly is deposited into the spacial places in the metal. I'm under the assumption that the sulfur would not harm a catalytic converter - it that part true?
Is there a clear cut answer as to why oil companies have ventured away from moly as an additive? I've heard of costs, but that doesn't have the ring of truth to it to me.
Good question. I think MoS2 bonding might be an electric dipole force, which is sort of second order from electric field force.
From 1972, Journal: "Wear"
A study of the lubricating mechanism of molybdenum disulfide
R. Holinskia and J. Gänsheimera
aDoẇ Corning, MunichGermany
Received 20 November 1970;
revised 26 August 1971.
Available online 10 February 2003.
Abstract
The structure of MoS2 and other layer lattice materials is discussed in relation to their effectiveness as lubricants and the mechanism of their lubricating actions.
The mechanism of the lubricating action of MoS2 was studied and compared with that of other materials by scanning electron microscopical investigation of specimens tested in the LFW-1, Almen-Wieland and a deep drawing machine.
The lubricating properties of MoS2 have been explained by the strong polarization of the sulfur atoms which produce a layer structure, good adhesion to metal surfaces, adhesion between MoS2 basal planes, easy sliding of MoS2 lamellae and the formation of a homogeneous continuous film. It is now shown that the load carrying part of the MoS2 film lies only on the asperities of the metal surface.
Wear
Volume 19, Issue 3, March 1972, Pages 329-342
Originally Posted By: Bruce T
Here are some previous posts about moly from MolaKule:
There are many chemistries for friction modification, anti-wear, and Exreme pressure.
Moly is but one of them. In low concentrations, it acts as another friction (reduction) modification additive, in medium concentrations it acts as a friction modifier and anti-wear, at high concentrations it acts as mainly as an EP agent. There is nothing majic about it, it works, just like ZDDP.
The most important thing is to realize that MolaKule is talking about the organometallic forms of Mo, not MoS2.
Ed
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