Moly and other additives: is the desired effect immmediate or gradual?

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If one begins using a synthetic oil with moly after dino oil without, is the protection afforded by that element--and any other additives for that matter--immediate or is there a period of conditioning of the engine parts involved. Of course there are variables to consider, but just in general, how does this work? [ January 21, 2003, 12:10 AM: Message edited by: YZF150 ]
 

Patman

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The moly can take up to a few thousand miles to fully plate up on the metal, so that's why the first interval with an oil with moly won't show the best results, the results will get better on the followup interval once the moly has fully plated up. [ January 21, 2003, 05:14 AM: Message edited by: Patman ]
 
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Patman - Currently I'm using Red Line 10W30 which is very high in moly. Do the internals actually remain plated when the oil is drained or is all the moly in the drain pan? I'm running it 5K for this first interval.
 

Patman

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It is my understanding that when you've used a moly oil for a while, and then you drain it out, the moly remains in place for a while, but eventually if there is no more moly in the new oil, the moly will deplete itself. Bob or MoleKule can explain it better than me.
 
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quote:
Originally posted by Patman: The moly can take up to a few thousand miles to fully plate up on the metal, so that's why the first interval with an oil with moly won't show the best results, the results will get better on the followup interval once the moly has fully plated up.
Okay, now I'm confused. I thought the moly was an EP additive that only came into play when the oil film was broken and metal to metal contact occurred. Like ZDDP, it would only plate up under those conditions. Can we clear this up? MoleKule? Does moly in oil start plating up all the metal as you use the oil, or does it just plate up at an EP point when needed? [Confused]
 

MolaKule

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The term "plating-up" is kindofa misnomer. I prefer the term "uptake." When the oil carries either the Zinc Alkyldithiophosphate (ZDDP) or Molybdenum Trialkyldithiocarbamate (MoTDC) in solution to the metal surfaces, they both behave as friction modifers (under light load) and when heavy loads are applied, they go into their Anti-Wear/EP modes; ZDDP at lower temps and lighter loads, and MoTDC at higher temps or higher loads. For moly, the molybdenum-sulfur-carbonate mixture forms a three-tiered set of layers (now containing molybdenum-sulfur-ferrous-carbonate) such that, when loads are applied (and surface temps go up due to pressure), the layers slide upon one another as a plastic layer of fluid, reducing friction and separating the metal surfaces. For engines that have never run a moly additive before, the moly from an oil with this additive will show some "uptake" to the surfaces. That is, you will generally see some of the moly coming from the oil solution and adhering to the metal pores. This shows up as a subtraction of moly from the virgin oil solution. So the answer is, the moly starts coating the metal as soon as the moly oil circulates, but the AW/EP action only occurs when the loads cause a pressure and temperature high enough to create this "plastic" interface. From the gas law in chemistry, PV = nRT, the Temperature is a function of pressure, (T = PV/nR), so when the surface pressure (load) between two adjacent surfaces cause the temperature to reach about 450 F or higher, then plastic flow on the surface occurs, inhibiting surface wear. (P is pressure, V is volume, R is a constant, and n is the amount of substance).
 

MolaKule

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Uptake depends on engine size and design, operating temperatures, etc. On the average, moly uptake will be about 30 ppm to as much as 100 ppm during the first run. Since the moly is very stable (more so than ZDDP), replenishment is done by the oil change.
 
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I'm not clear on this, but is Moly, being fairly new to oil, absolutely safe? It's been batted around before that it can come out of the oil and this is why some dont use it.
 

Patman

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quote:
Originally posted by buster: I'm not clear on this, but is Moly, being fairly new to oil, absolutely safe? It's been batted around before that it can come out of the oil and this is why some dont use it.
It's not really new to oil, it's just that it's catching on more lately. It's been in oils for decades now. Schaeffer oil was one of the first, if not the first, and I believe it was in the 60s they started adding it.
 
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quote:
From the gas law in chemistry, PV = nRT, the Temperature is a function of pressure, (T = PV/nR), so when the surface pressure (load) between two adjacent surfaces cause the temperature to reach about 450 F or higher, then plastic flow on the surface occurs, inhibiting surface wear. (P is pressure, V is volume, R is a constant, and n is the amount of substance).
THat's the ideal gas law. It's a combination of Charles' and Boyle's law. How does that apply to oils and metals?
 

MolaKule

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metro, There are many types of fluids, with gas being one of them and oils being another; just different viscosites and different constants of proportionality. If we assume constant Volume, the Temperature (T = PV/nR and replacing P = F/A, so T = FV/nRA), increases as the pressure (load force) goes up. The constant for gas is replaced with a constant for lubricating fluids. Also recall that in an engine one form of energy (mechanical) is transformed to other types of energy (thermal) and vice versa. So as the mechanical forces increase, the fluid is squeezed, increasing pressure, and thus heating the interface, causing plastic flow of the anti-wear additive - this plastic flow keeps the metal surfaces from contacting. Edit: Think of the lubricating fluid under pressure as a nonideal gas under the influences of the "van der Walls" molecular forces. [ January 21, 2003, 09:07 PM: Message edited by: MolaKule ]
 

YZF150

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Besides depletion of moly, are there any other forces at work on a first run of synthetic such that an oil change sooner rather than later is in order? How much sooner?
 

YZF150

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How extensive is the uptake, hence depletion, of the moly in solution in a new engine with a first fill of moly-containing oil? What does this indicate for when that first fill should be drained and replaced with a fresh charge of moly/oil?
 

Patman

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quote:
Originally posted by YZF150: Besides depletion of moly, are there any other forces at work on a first run of synthetic such that an oil change sooner rather than later is in order? How much sooner?
It depends on the mileage on the engine and how long it's been run on conventional oil. A high mileage engine run on conventional oil may be more dirty inside, so the use of synthetics (many of which contain better cleaning action) will cause the first interval to be one that puts a lot more dirt into the oil filter. So if you think an engine might be pretty dirty, keep the first interval with synthetic below 5k. The better idea though, would be to run a Neutra or Auto-rx treatment through the engine first before converting a higher mileage engine over. If the engine is still relatively new, just switch over to synthetic and don't worry. You still don't want to go to super extended intervals on the very first run though (10k plus that is) simply because the slight mix of the old oil will cause that synthetic to not retain it's TBN as good on the first run.
 
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Looking to settle a debate at my garage. Can I get an answer from an Amsoil Rep/Dealer or someone from Lubrisol/Amsoil's staff. [Smile] I am a bit of a novice, but I am learning. I have noticed that Redline uses moly in their oil and now Mobil1 is useing it too. At least that is what I've read here. Is it a cost saving thing? [Confused] I am woundering why Amsoil is so set against it's use. What are the pro's and con's of it's use inside an internal combustion engine. [I dont know] P.S. I did read many posts here re: moly, but none gave me the answer straight up and simple. Thanks!!!
 
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I can not speak for Al or for the chemists/marketers at Amsoil HQ. It is my viewpoint that Amsoil does not feel/think Mo compounds are necessary in Amsoil motor oils. I have NO concept if they are running tests or even thinking about Mo. I think we can on paper say there are some beni's of SOME Organo/Thio Mo compounds but I personally do not see them as the magic bullet. Yes, they (Mo) can be used along side of ZDDP, and therefore P compounds can be lowered, but then again the alleged reason for lowering P (supposed cat poisoning) hasn't been proven with ZDDP..... In SCIENTIFIC double blind studies do Mo compounds lower wear, prevent all forms of galling, increase oil life, etc? The jury is still out IMHO.
 
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Thanks Pablo, ...but your answer was a bit over my head. I am a novice remember. [Big Grin] Can you put it in laymans term ... *** What are the Pro's and Con's of using Moly in an internal combustion engine? [I dont know] Thanks again !!!
 
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I would think that a control test for the effect of moly would be to start with an oil with no moly and then add increasing amounts of moly to it on subsequent oil changes. Assuming similar driving patterns, equal mileage and well broken-in engine (20-40k), we should observe any wear changes. Ideally one would need several vehicles of exact model and mileage and compare them side by side under the same conditions except for moly content. This would be expensive and possible only if your friend is a fleet mechanic for a corporation. [Smile]
 
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quote:
Originally posted by red2rebel: Thanks Pablo, ...but your answer was a bit over my head. I am a novice remember. [Big Grin] Can you put it in laymans term ... *** What are the Pro's and Con's of using Moly in an internal combustion engine? [I dont know] Thanks again !!!
What it boils down to is that no one has proven any downside to having moly in motor oil. As far as the upside, it's easy to see that "in theory" wear numbers should be better with moly in the oil, but from what I've seen of the oil analyses on this board, I'm not so sure that's the case. As Pablo points out, a completely blind comparison of an experimental oil where the only variable between the two samples would be the moly would (probably) show for sure whether moly does indeed decrease wear.
 
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