Originally Posted By: Jim Allen
Originally Posted By: BuickGN
I have yet to see proof of this. Oil flows nearly instantly with whatever you use assuming it's right for the climate. The difference in time to pressure and flow of a 5w-20 and 5w30 would have to be measured in miliseconds. I couldn't see a difference in the oil pressure light or actual flow out of the valvetrain from a 10w30 to a 20-50.
Poiseuille’s Equation: The volume flow rate is inversely proportional to viscosity.
Isn't it a fact of physics that oil at a given viscosity flows more slowly at lower temps than it does at a higher one? There are likely a million ways to scientifically prove that your rockers got MORE of the 10W30 than they did of the 20W50. Maybe you are getting ENOUGH flow (as measured by your calibrated eyeballs) in the idle situation you describe but what about at 4000 rpm?
I just don't see the sense in running an oil thicker than is needed for a particular combination of circumstances (temp and operating condition). Beyond what you need is just a waste of energy. I don't think you, or anyone, can prove running a thicker oil than necessary results in any notable improvement in longevity or wear.
Wouldn't everyone agree that, in the end, it's more important to have the RIGHT viscosity. Arguing over thick or thin is only looking at part of the equation. What's "right" varies according to many conditions and can't necessarily be judged from only one perspective
My comment about oil getting to the valvetrain was about the time it takes for oil to get there, not how much flow there is. My eyeballs do a fine job, thanks for the smart [censored] comment.
The oil pump is a positive displacement pump. It should pump the same volume but at a higher pressure with a thicker oil assuming it's not in bypass.
Get off your high horse, you're basing everything in theory. I've run this engine family for the past 14 years, I know a couple things. My engine flat out won't live on a thin 10w30 period. I've proven it with multiple teadowns. The thin stuff won't keep parts separated. What's this new obsession with flow anyway? If the parts are kept separated and at a reasonable temp why do you need a higher flow? I don't need to defend myself to every know it all that comes around.
Back to the topic, how does the 5w-20 provide better startup protection if there is no difference in time to full pressure vs a 10w30 or 20w-50?
Originally Posted By: BuickGN
I have yet to see proof of this. Oil flows nearly instantly with whatever you use assuming it's right for the climate. The difference in time to pressure and flow of a 5w-20 and 5w30 would have to be measured in miliseconds. I couldn't see a difference in the oil pressure light or actual flow out of the valvetrain from a 10w30 to a 20-50.
Poiseuille’s Equation: The volume flow rate is inversely proportional to viscosity.
Isn't it a fact of physics that oil at a given viscosity flows more slowly at lower temps than it does at a higher one? There are likely a million ways to scientifically prove that your rockers got MORE of the 10W30 than they did of the 20W50. Maybe you are getting ENOUGH flow (as measured by your calibrated eyeballs) in the idle situation you describe but what about at 4000 rpm?
I just don't see the sense in running an oil thicker than is needed for a particular combination of circumstances (temp and operating condition). Beyond what you need is just a waste of energy. I don't think you, or anyone, can prove running a thicker oil than necessary results in any notable improvement in longevity or wear.
Wouldn't everyone agree that, in the end, it's more important to have the RIGHT viscosity. Arguing over thick or thin is only looking at part of the equation. What's "right" varies according to many conditions and can't necessarily be judged from only one perspective
My comment about oil getting to the valvetrain was about the time it takes for oil to get there, not how much flow there is. My eyeballs do a fine job, thanks for the smart [censored] comment.
The oil pump is a positive displacement pump. It should pump the same volume but at a higher pressure with a thicker oil assuming it's not in bypass.
Get off your high horse, you're basing everything in theory. I've run this engine family for the past 14 years, I know a couple things. My engine flat out won't live on a thin 10w30 period. I've proven it with multiple teadowns. The thin stuff won't keep parts separated. What's this new obsession with flow anyway? If the parts are kept separated and at a reasonable temp why do you need a higher flow? I don't need to defend myself to every know it all that comes around.
Back to the topic, how does the 5w-20 provide better startup protection if there is no difference in time to full pressure vs a 10w30 or 20w-50?
