Reminds me of the guy recommending the very heavy EP gear lubes for his CS Listeroids. I guess that 140 wt. would tend to close up some of the gaps and loose clearances...
I have heard and read various comments - especially about compatibility of additives, and have experienced severe oil gelling in some of our air-cooled NG Listers. Polymerized oil is an absolute nightmare to get back out of a pressure-fed oil system.
Combustion of diesel fuel produces differing compounds (as far as the lubricating oil is concerned), from gasoline combustion.
In a nutshell (and severely abbreviated): Not "rocket science" except perhaps for the testing and design phases of product development.
Besides lubricity and viscosity characteristics, the additive package is the next important factor in determining the performance level and design of a modern lubricating oil.
Corrosion prevention is one of the major factors in particular that a diesel engine oil is designed to deal with (besides wear and deposit control) ... The idea that an off-spec oil will directly "cause" corrosion is a fallacy, however, in a diesel engine with substantial Sulphur compounds entering the lube oil and becoming acidic - bearings will erode as a result. The modern API CD rated oils are buffered to reduce or prevent this from happening. API SG or gasoline engine rated oils may not have this same performance characteristic. The net result can be bearing corrosion from acidic oil if using lesser grade oil without the correct additives.
Use a diesel rated oil API CD, CE, CF and so on in your Lister slow-speed. Change it frequently even if the engine is not run a lot of hours.
Each engine manufacturer has come up with their own set of recommendations based on a long list of oil system performance data that is very well documented and explained. See "Engine Manufacturer's Association" publication EMA Lubricating Oils Data Book.
dieselgman