Offshoreonly.com - Amsoil VS Walmart Mobil One

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This topic of oil has been debated many times over the years. I've used the Merc and Quicksilver both as well as Mobil in engines past. Now in the new 525efi whipples I'll be using the Castrol 20w-50 due to that's what Eddie Young says to run in those. He recommends that in all of his engines, so since he built them I'll run what he says. Especially since it is way cheaper than a lot of the other oils. Wix filters are the ones I'll use for sure and have used them many times in the past.

Yup, less than $25 for 5 quart jug 20w-50 vr1 conventional

https://www.amazon.com/gp/aw/d/B07ZCQZ771

Quote:

Originally Posted by Keith Atlanta (Post 4830036)

Personally, I think 15-50 is too light. As a bargain, 20-50 Mobile 1 at Walmart is a good deal, but for a few bucks more, you can have Amsoil Dominator 60wt. Which is great stuff. With BigBlock applications, 496Mag/HO and 525 style engines the oil pressure maintains better even after hard runs, its specifically made to assume a lot of gas ends up in the oil, the oil lasts wayyyyy longer than conventional 20-50 so at the end of the day, Dominator 60wt really doesnt cost more since it can stay in your engine much longer. When my Mobil 1 was dirty, the dominator was still red and clean.

The 15w is only a weight rating for cold temperatures and matters very little for boats. It still has a 50 weight viscosity rating at normal operating temperatures. Oil pressure is the restriction of flow. If you put 90 weight oil in your engine the pressure would be higher, but the flow would actually be lower. The 496 engines were designed for Merc 25w-40, so any oil with a 50 weight rating is more than enough. When oil gets dirty, that means its doing its job and removing contaminants from the engine.

Quote:

Originally Posted by Griff (Post 4830102)

AND, keeping those contaminants in suspension (detergent effect).

Quote:

Originally Posted by Griff (Post 4830102)

When oil gets dirty, that means its doing its job and removing contaminants from the engine.

Six of one, half dozen of another. Only in terms of Dominator 60, because I love that stuff, my engines always ran cooler and a testament to that, I think its clean because the engine parts arent wearing to begin with due to the superior oil film hence lower temps.

...and now we are into a full-on oil thread

Quote:

Originally Posted by Keith Atlanta (Post 4830215)

Imho, Most of the dirtiness you see is combustion byproducts from blow by.

Quote:

Originally Posted by SB (Post 4830216)

Imho, Most of the dirtiness you see is combustion byproducts from blow by.

Yep. Oil doesn't turn black because it's all full of worn internal parts. It turns black because of suspended particles of burned or partially burned hydrocarbons.

That 60wt is probably to thick to catch particles 😉

And many oils are different colors and shades of colors new. :)

I've always like Valvoline VR1 20/50 because of the added Zinc content but I'm not a scientist or expert on the fundamentals of molecules in oil and how much none of that makes a difference with how often we all change the oil in our boats. Sometimes it comes down to availability and what you can always rely on being able to get. Being in the automotive industry everything is getting harder to get (oils, filters etc.) so always buy extra!