Synthetic oil choice

[d00df00d]

Originally Posted By: livehho
I wish there was some 'motor oil bible' or something. Some centralized information source about everything you need to know about this topic. That would really really help I think. This site looks completely devoted to motor oil so that's a good start.

That would be one BIG book...

It would also continually evolve as circumstances change, new developments are made, and our understanding improves.

In other words, if there were such a "bible", you'd have to be extremely skeptical of it.

 

[RTexasF]

Quote:

Yea man.. it's crazy stuff. All the info, articles, mechanic advice, forums.. they all give you their truth. Pure dogma. It can drive you nuts sometimes. So many questions. You always get half of the story. I wish there was some 'motor oil bible' or something. Some centralized information source about everything you need to know about this topic. That would really really help I think. This site looks completely devoted to motor oil so that's a good start.


Even oil company execs come to this site. Here you will get the straight scoop on most everything oil related. This is as close to nirvana as it gets when discussing oil.

 

[livehho]

Originally Posted By: Rand
5 isnt a viscosity rating its a number referencing its low temperature pumpability at -30C(or is it -35C?)( for 5w-XX)

viscosity is very complicated and not easy to wrap your head around.

a 5w20 is thicker at 40C than a 20w50 at 100C... much thicker.

etc. Oil Viscosity ratings/numbers is one of those numbers that is misunderstood by most people.


Tire ratings are another.. The whole speed rating vs handling

or aspect ratio vs height... sigh.




yea why all the REAL data is not available to the mainstream. they only publish the makeup. iguess if you dig deeper you can put together all the pieces. but it should not be that way.

 

[livehho]

Originally Posted By: d00df00d
Originally Posted By: livehho
I wish there was some 'motor oil bible' or something. Some centralized information source about everything you need to know about this topic. That would really really help I think. This site looks completely devoted to motor oil so that's a good start.

That would be one BIG book...

It would also continually evolve as circumstances change, new developments are made, and our understanding improves.

In other words, if there were such a "bible", you'd have to be extremely skeptical of it.

what do you think of this?

http://www.zag.si/~jank/public/bmw/oil_bible.pdf

You have any input on the guy who wrote this?

 

[d00df00d]

That's a good starting point. However, there are some caveats:

It's really an Amsoil product. It claims to tell you how to make an "intelligent" choice about motor oil, and then lists criteria that are favorable to Amsoil, such as four-ball wear test performance and a bunch of parameters that not all motor oil companies disclose. It also portrays other things in ways that are favorable to Amsoil, e.g. PAOs and esters are the only "true" synthetics, API specs don't mean much, etc.

One thing that really sticks in my eye is that it doesn't say anything about OEM certifications. A lot of those, like Honda HTO-06 and Mercedes 229.5, are VERY stringent and totally sufficient to guarantee good performance in the vehicles that require them.

It's also old, and fails to include a lot of the newer developments in stuff like group III base stocks and such.

The worst part, IMO, is that it claims to be all you ever need to know. That idea is a HUGE red flag for me. It means "stop asking questions, take my word for it, and don't even admit the possibility that things change." Nobody ever talks like that unless they have something to hide or depend on people's ignorance.

However, like I said, it's not a bad starting point. I'm pretty sure you can trust most of what it says about the chemical composition of oils and what goes into making a good one in general. Take it as one piece of the puzzle.

 

[Steve S]

Originally Posted By: livehho
As I understand, as the additives wear out (in conventional oils) the oil reverts to its true weight, the lower number, 5 in case of a 5w30 for example.. that's why it's recommended a higher weight number, so it does not get very thing as the additives wear out. That makes total sense. IN THE OTHER HAND, synthetics have very little additives; therefore, they do not thicken much when cold nor thin much when hot... so...

So my question is: Would there be a problem in using a full synthetic 5W-50 in hot weather? and have the best of both worlds?

- protect engine wear at strart-up (5w)
- protect engine wear at operating temps (50)

So it will flow much faster than a conventional motor oil during initial start-up, yet at normal operating temperatures it will act like a regular Grade 50 oil.

I know that in hot weather it's recommended a 15w or 20w.. but if you use full 100% synthetic (AMSOIL, Mobil 1) you could use a much lower W number to help the engine at start up.


In Fla? you won't get any start up help with a syn oil. Also conventional will get into every nook and cranny just like syn oil"just in case".