Talks about synthetics and conventional oil, but in terms of heat resistance.

Also goes over the factors that make you change oil at the correct intervals:

http://www.carcraft.com/techarticles...ech/index.html

Basically, a synthetic oil can handle oil temps of 300 degrees farenheit and not break down (molecularly). Whereas, you don't want to go over 275 with conventional. Mobil 1 claims 400*.

ALSO, they said that for every pound of fuel you burn, a pound of water is made as part of the combustion process. Some of that water gets in the pan. It will stay there and continue to pump unless the oil goes OVER 212* which is the boiling point.
So it is important to "Get on her" every once in a while to ensure that the water steams and can exit through the PCV or exhaust.

THey talked about fuel being a contaminant, and that it will circulate for a long time because its boiling point is so high. Anyone who has had excessive blow by knows that. SO, if your oil breaks down and you don't get that good piston ring seal, then fuel enters the oil and changes the molecular structure of the oil. That is why i use lucas additive and change at 3K mile intervals. That way the fuel doesn't tarnish the engine parts and cause the baked on sludge.

So all the talk about detergents is more mythical. I think it has to do more with temperature, how fast the oil breaks down, and viscosity. Fuel in the oil will cause more crud to curculate, because gas is a strong solvent that dissolves carbon and thins the oil. SO the crud will continue to circulate.

Thanks to hey you for the car craft article that led me to click more links.

 

I like the fact that there talking about oil, yet there's a Valvoline ad to the left of it...

 

yeah, but they were interviewing an engineer from Quaker state.

 

thats some good info, and sounds logical....

 

If you want more information than you can possibly ever digest on the subject of motor oil go to Bob is the oil guy.If they havent covered it,it aint happened.These guys are oil fixated.