Interpreting a comparison of two marine oils

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1
I'm new to the board and apologize if this has been covered elsewhere in the forum; I searched around but could not find anything specifically.

I'm no motor oil expert and need to determine whether two marine oils are functionally equivalent (or at least similar), in the view of folks who know more about oils than I do.

Would anyone be wiling to take a look at the PDS data that I have extracted below for each of the two products, and let me know your quick thoughts? It seems to me that given the sizable differences in viscosity, flash points, and ash content, that these are NOT comparable marine oils--but like I said I'm new to the board and to motor oils, so I could be overblowing the differences in those attributes. I don't want to make this about brands but if the brand names/product names are needed to answer the question, I can certainly provide them.

Thank you very much!

Product 1Product 2
Density at 15 deg C0.8990.890
Viscosity mm2/s at 40142.0102.5
Viscosity mm2/s at 10014.511.6
Viscosity index100100
Flash point deg C272240
Pour point deg C-9-18
Sulfated Ash, wt %2.101.67
Base number15.012.0
 
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2,912
Location
Georgia/Retired
I'm going to say they are an SAE 30 and an SAE 40 mineral oil offering. Your choice for these products would depend on your application. What does your engine builder specify? These oils obviously have no viscosity index modifiers and I'd say are a straight group I mineral oil with heavy detergent package. The functional difference between the two is going to simply be the viscosity.
 
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25,550
Location
Upstate NY
Many people run a 15W40 oil in a marine engine. Often the engines don't get hours on them over the summer to wear out the oil so its just changed in the fall.

Most marine engines die of water ingestion.
 
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937
Location
Colorado, USA
I was going to say they are similar to conventional VR1 40 weight and 30 weight. However the pour points are not nearly as low as what Valvoline shows, these are higher in ash by a good amount, TBN is “off the charts” relative to Valvoline. I am stumped, other than I would say 40w and 30w.
 
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1,271
Location
Muncie, Indiana
I was going to say they are similar to conventional VR1 40 weight and 30 weight. However the pour points are not nearly as low as what Valvoline shows, these are higher in ash by a good amount, TBN is “off the charts” relative to Valvoline. I am stumped, other than I would say 40w and 30w.
I searched and found that the 30 weight seems to match Chevron Delo 1000 Marine oil, which sounds like it's probably for Ship engines more so than boats, https://cglapps.chevron.com/sdspds/PDSDetailPage.aspx?docDataId=77248&docFormat=PDF , I wonder maybe if it's just solvent refined oil while that VR1 is probably a higher quality group II oil.
 
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937
Location
Colorado, USA
Messages
45
Location
Long Island NY
While there have been many debates about whether or not the NMMA rating for corrosion resistance really means anything, I can share these pics of my engine which was run on the Merc/Quicksilver 25/40 NMMA oil. What happened was that both head gaskets blew and the engine had salt water in it for approx 1 week maybe a bit longer. Here is a pic of the tear down, notice the lack of rust on the valve train. Oil looked like a milkshake but the pushrods, lifters, rocker arms, etc all were rust free. So maybe it does make a difference. The water intrusion that kills marine engines, though, is really because of faulty corroded exhaust elbows or manifolds, or a hole rotted in a cyl head from years of raw water cooling.
 

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522
Location
MD
OP - would say those 2 oils not equivalent. Of course, not knowing the add pack or what type of engine(s) really makes this a game of guesses.

LouC - consistent with what I've seen. When compared, the nmma oils typically are better at preventing corrosion. Must be some extra stuff in them, which doesn't show up in oil analysis.
 
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