If I understand the way moly "works" in a motor oil, it's only going to plate the metal at a point where the hydrodynamic oil film is broken. Therefore, unless something drastic happen to cause metal to metal contact, the moly doesn't even come into play. It's not in there platting up everything just because it's in the oil.
quote:Originally posted by Bighank:
I read on the site about a diesel manufacture
warning not to use moly with roller lifters.
Would this be a problem with gasoline motors
with roller lifters, as the Mopar 360 Magnum?
They probably were talking about crystalline MoS2, not soluble MoTDC. Big difference. I think we all agree, don't use molybdenum disulfide in the crankcase oil. Molybdenum trialkyldithiocarbamate or a related compound works very well in crankcase oil.
I think you may be referring to Cummins engine bulletin #3810340-02 dated 5/96. This paper discusses the possibility of molybdenum Dithiophosphate causing problems with some copper components within the engine and the use of copper de-activators in the oil to compensate. I no longer have this, so I am going from memory. Nothing was ever published or stated since that time that I am aware of.
I now have 2 PSD's using Schaeffer's 15W40 with moly and the analysis on my 01 are super and in the analysis section. Extremely low wear, and metals, ox, nit, soot etc.
Some oil company dealers still like to quote this old info as a revelation to sell their product. The knowledgeable ones don't and sell their oil on it's own merit. IMO
I don't think you'll have any problems with the current moly being used, since the moly is Molybdenum Dithiocarbamate (MoTDC) and not Molybdenum Dithiophosphate (MoDTP; two different types of sunthetic moly. Molybdenum Dithiocarbamate (MoTDC) is the most stable form of moly to date.
In addition, it was only "suspected" that the molybdenum Dithiophosphate was causing a copper corrosion problem and never really proven.