Cold engine max REV

Synthetic oil that's 5W30 shouldn't be a redline issue as long as you're not living at the North Pole. The issue with synthetic is it tends to run off parts so when you initially start the car, the oil coating on the cylinder walls etc may be thin. But in a few seconds the oil pressure is up and you're redy to go.

That's a new one... where did you get that information from? I have always heard that synthetic oil coats engine parts better and causes less wear at initial start-up. This only makes sense since the oil viscosity is maintained at high temps better than conventional oil, and the engine is at high temp when it was turned off.

The fact that the oil is thinner when cold only makes the oil pressure come up faster when the engine is first started.

-Fred W

John,

The above experiment *might* be valid if the oil was at room temperature when you shutdown your engine. Obviously it is not. In order to do perform that experiment correctly you should heat both oils in a saucepan to 190 degrees F or so and then see which runs off faster. It will be the conventional oil.

You see, all oils get thinner with increased temperatures. That's simple physics. The big *advantage* of synthetic oils over conventional ones is that it can maintain viscosity better at increased temps while also being considerably thinner at lower temps.

If someone could somehow invent an oil that the had reverse temperature characteristics they would surely become rich.

-Fred W

I tried fully synthetic in my old Rover V-8 with some 150,000 miles. And if left more than a few days unused, got some what I reckon was big end knock at startup. Not if just left overnight.

Changing back to semi-synth has cured this.