Synthetic Oil Question

[spressomon]

Well, just keep in mind that Haas dude is not a lubrication engineer and his piece there is opinion only.

I choose operating temp viscosity (the 30 in 10w-30) based on the Toyota recommendation for my engine in Australia. The USA recs are compromises with the government that may allow for slightly better fuel economy at the cost of lower operating life. Both the 60 and the 80 recommend 10w-40 or 20w-50 in these vehicles in Australia. Since my summer operating temps are similar and the winters where I live are mild, that's roughly what I run, thinking Toyota knows more than Senor Haas.

Based on published oil analysis, the 1FZ motor does especially well on Mobil1 0w-40. That's almost always what I run in the 80. It also does well on Mobil1 15w-50, again based on published oil analysis and I do run that in the summers. My 60 usually has Delo 15w-40 in it, (though for this winter it's had Rotella Syn 5w-40 as an experiment) and my 40 always has 20w-50 in it, since it's ahhh, well used.

BTW-all automotive oils are thicker when cold and thinner when hot. There is no magic there.

In the end, though, comparison data is lacking, to show that synthetic oils allow a motor to last longer than conventional oils. OTR trucks go 800,000 to 1,000,000 miles between rebuilds and most of them get run on Rotella and Delo conventional oils. My own *theory* is that having a change interval and sticking to it like religion, is more important than whether you run synthetic or conventional lube oils.

Ditto on the consistent change interval. I believe most OTR rigs utilize bypass filtering (my Uncle was a big rig driver...that info came from him). That, as far as I understand, really helps keep the oil cleaner/better filtered.

Also factoring your type/style of driving and the climate into your change intervals seems prudent also.

 

[madizell]

One of the concepts that link I posted repeatedly mentioned was that oil doesn't thin with heat, it thickens with cold. Seems trivial, but it is an important distinction.

I would say that it is a distinction without a difference. The argument is about relativity, not about characteristics of oil or any other liquid. Hotter, colder, thicker, thinner, are all relative terms. Without knowing "relative to what" the distinction is semantic, not technical.

 

[Pskhaat]

...based on the Toyota recommendation for my engine in Australia. The USA recs are compromises with the government that may allow for slightly better fuel economy at the cost of lower operating life.

Though I generally agree, the Toyota engines (please correct me?) have some smog differences such as EGR (do int'l spec'd have EGR?) which when in place as I understand reduces the combustion temperature, and as such may indeed be on the cusp for a `lighter' oil.

 

[ntsqd]

I would say that it is a distinction without a difference. The argument is about relativity, not about characteristics of oil or any other liquid. Hotter, colder, thicker, thinner, are all relative terms. Without knowing "relative to what" the distinction is semantic, not technical.

Yeah, in and of itself it's mostly semantics, but what I think important in it is how it changes your approach to the topic. Or can change your approach. Sometimes getting the best answer depends on what frame of reference you started from.

As to Haas being an MD & not a Tribologist, true. That's the reason I'm not saying his articles are "The Word", just an appearently informed person who has done some research. Right or wrong, his articles are thot provoking.

As I understand it EGR is only operational during light load, part throttle cruise. During heavy loadings of the engine the EGR is turned off. EGR is essentially a displacement reducer. By introducing a small volume of inert gas into the intake each cylinder behaves as if it were that much smaller. So in the sense that there is less fuel and air to burn it does reduce the heat energy in the cylinders, but my understanding of it's effect on the tempature of the combustion is that it is not huge.

 

[madizell]

What are the benefits of running syn oil?

Ran into this tonight. Perhaps you have not seen it before:

http://www.tucsonoffroad.proboards107.com/index.cgi?board=gentech&action=display&thread=920

 

[daverami]

Hey, thanks, hadn't seen that article before.