The Problem w/Fuel Dilution is not Viscosity Drop
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Originally Posted By: BuickGN
Has anyone actually proven that thicker oil increases startup wear? I see it here over and over but never any proof. I'm talking within reason, not using a straight 60 weight in -20F conditions. I see oil coming out of my rocker arms on the Buick with 20-50 the second the engine fires.
Originally Posted By: BuickGN
I know exactly what you're saying but it's not residual oil left in the pushrods and being flung out by the rockers. Flow is even from the get go. FWIW, this was done with the valvecover off.
Another thing I observed when I put a temporary oil pressure guage at the turbo feed (top of the engine) with a see through oil line is instant oil movement. If the thinner oil gets there faster, it would have to be measured in miliseconds.
It's the same with my Jeeps running SAE30 or 10W40. My 2.5L Wrangler trail heep starts to build pressure as I crank it over. It flows to the rockers immediately. The 355ci in my Malibu drag car does the same. They both have high volume Melling pumps though.
Has anyone actually proven that thicker oil increases startup wear? I see it here over and over but never any proof. I'm talking within reason, not using a straight 60 weight in -20F conditions. I see oil coming out of my rocker arms on the Buick with 20-50 the second the engine fires.
Originally Posted By: BuickGN
I know exactly what you're saying but it's not residual oil left in the pushrods and being flung out by the rockers. Flow is even from the get go. FWIW, this was done with the valvecover off.
Another thing I observed when I put a temporary oil pressure guage at the turbo feed (top of the engine) with a see through oil line is instant oil movement. If the thinner oil gets there faster, it would have to be measured in miliseconds.
It's the same with my Jeeps running SAE30 or 10W40. My 2.5L Wrangler trail heep starts to build pressure as I crank it over. It flows to the rockers immediately. The 355ci in my Malibu drag car does the same. They both have high volume Melling pumps though.
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Quote:
There are several points for further discussion -
Thinner oil: reduces cold startup wear, more prone to film thickness/retention damage, burns off fuel quicker
Thicker oil: more cold startup wear, potentially more fuel dilution due to viscosity thickness resistance until warmed; potentially longer to burn off fuel dilution
Which is preferred for short distance commuters in addition to shorter OCI's??
How about the notion that anything to do with whether an oil is thick or thin in a cold start situation is moot since the stuff isn't thin (EVER) at cold start ..even if cold start is @ 130F ambient??
Does an above 70visc (at the moment) 5w-20 have a thin film formation? Does a 50 weight (at the moment) 5w-40 have a thicker one?
So, in that instance ..just why would one worry, in terms of fuel dilution, about viscosity (short trip where there is never any terminal or normalized visc)??
There are several points for further discussion -
Thinner oil: reduces cold startup wear, more prone to film thickness/retention damage, burns off fuel quicker
Thicker oil: more cold startup wear, potentially more fuel dilution due to viscosity thickness resistance until warmed; potentially longer to burn off fuel dilution
Which is preferred for short distance commuters in addition to shorter OCI's??
How about the notion that anything to do with whether an oil is thick or thin in a cold start situation is moot since the stuff isn't thin (EVER) at cold start ..even if cold start is @ 130F ambient??
Does an above 70visc (at the moment) 5w-20 have a thin film formation? Does a 50 weight (at the moment) 5w-40 have a thicker one?
So, in that instance ..just why would one worry, in terms of fuel dilution, about viscosity (short trip where there is never any terminal or normalized visc)??
Anyone know?
Originally Posted By: LargeCarManX2
Originally Posted By: Pablo
The bottom line here is that fuel is hard on oil. If the formulating chemists don't design a tiered system for handling fuel, the motor oil will be a weak one.
Can you elaborate on the tiered system for handling fuel?
Is it like a fast disolve pain pill for the first 4 hours with the second wave of less disolving pain medicine taking over after the first 4 hours? A multi-time pain pill so to speak?
Which chemicals/additives in this tiered system do this?
Originally Posted By: LargeCarManX2
Originally Posted By: Pablo
The bottom line here is that fuel is hard on oil. If the formulating chemists don't design a tiered system for handling fuel, the motor oil will be a weak one.
Can you elaborate on the tiered system for handling fuel?
Is it like a fast disolve pain pill for the first 4 hours with the second wave of less disolving pain medicine taking over after the first 4 hours? A multi-time pain pill so to speak?
Which chemicals/additives in this tiered system do this?
Sure. But it's nothing new. Just read the Molacule quiz threads.
No it's not really like gut ingested pharmaceuticals.
Just to rattle off a few, by and large some of the worst effects of fuel (partially or not all burned) are from oxidation. The oil will need a decent dose of anti-oxidants and dispersants/detergents to deal with the break down products. The oil will need a logical acid buffering system to handle the acid by products. It will need strong base oils (and VII's) to stand up not only to minor dilution, but mostly stand-up to the fuel hydrocarbons and fuel additives - because if the additive package is not doing the full job, it's the lubricating properties (as noted above) which will suffer.
No it's not really like gut ingested pharmaceuticals.
Just to rattle off a few, by and large some of the worst effects of fuel (partially or not all burned) are from oxidation. The oil will need a decent dose of anti-oxidants and dispersants/detergents to deal with the break down products. The oil will need a logical acid buffering system to handle the acid by products. It will need strong base oils (and VII's) to stand up not only to minor dilution, but mostly stand-up to the fuel hydrocarbons and fuel additives - because if the additive package is not doing the full job, it's the lubricating properties (as noted above) which will suffer.
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