Reply to "Oil Weight"

Oil is not a mysterious subject. Nor is there a need to be religious, you know, having a belief system. Just the facts ma'am.

Richard S. is a scientist, I respect his knowledge, I don't off hand find anything in the info Mark posted that I could argue. I especially agree with him that the idea of extended change intervals with synthetic oil is wrong. And even though the write up Mark shared with us is a long one, it barely scratches the surface of the topic of lubrication. Which is why I've been hands off here, I guess I don't want to get into a situation where I needed to type a long post. I have other priorities this week. The Chevron Delo stuff I'm sure is good mineral oil. If it has ZDDP content, it may make good break in oil. Or a good recommendation for a high mileage motor. But in this day and age there just isn't even a contest between mineral oils & the better synthetics. The race isn't even close.

The auto industry conducts tests. In the automotive world (as opposed to aeronautic), the "pure" synthetics are superior to mineral oil based lubricants due to their superior high temp oxidation resistance, high film strength, very low tendency to form deposits, stable viscosity of the base and low temp flow characteristics. There are ways to measure these properties and make comparisons. Amsoil, Mobil 1 & Spectro are the synthetic oils normally given the highest ratings in these areas. Mobil 1 is the value leader of that group.

One subject I want to touch on is the viscosity issue. Straight 30 weight oil is a good recommendation in Texas, here in So Cal where I live too. But not for someone living in Minnesota, or New York. And if you are going to race a motor, using mineral oil (why?) then by all means, run a single weight type oil, like 30 weight. There is nothing to fear about multi-viscosity oil, as long as you understand the nature of those oils. Yes the viscosity enhancers do break down with use, and yes the molecule will have less shear strength than those of the single weight oils because they are made from cheaper crude. But if an owner is going to run a multi-viscosity mineral oil then by checking the oil periodically they can determine at what point the oil begins to change color, and at what point it loses its "tackiness", and thereby determine at what intervals the multi-viscosity oil should be changed in that particular motor. Its not the end of the world or anything, a motor can operate a long time and remain in good shape on multi-viscosity mineral oil, if it is changed at the proper intervals.

However if you run synthetics, it pretty much becomes a non issue again. The synthetics run circles around the mineral oils in terms of viscosity stability. In fact, Amsoil manufactures an automotive oil, rated 20W50, that has NO viscosity enhancers in it, it is naturally 20W 50, its a very bitchen oil, but expensive.

your slippery friend on the DTBB