Oils and Things, Oil Tech Discussion

[07GTS]

i use to run a 10-60 in mine at the start when blower was fitted but then tried a 10-40 and it went quieter so i have stuck with that since then, and as i always say once i checked bearings once engine was out they were barely touched for stock bottom end and 14psi boost adding load to it all for few years so the 40 was working well

 

[Fu Manchu]

This is why your bottle of oil has 2 numbers! Because it has 2 weights!
The first one is the weight when cold, and the second is the weight when hot.
Just remember, to make things a little bit more confusion they measure the cold viscosity and hot viscosity on different scales. So don't bother trying to relate the 10w cold number to your 40 hot number. The oil still things out a lot when it's hot.
So 10w oil is thicker than 5w when it's cold. But 5w40 and 10w40 are very similar when hot because both 40 grade.

It’s not going to end well is it?

 

[chrisp]

This guy always gives good explanations, and he has a couple of graphs/figures showing the meaning of the viscosity numbers…

 

[losh1971]

It’s not going to end well is it?

Well Fu, you just had to start a thread on oil. How did you think this would end?

Word of advice DO NOT start a tyre thread... An oil thread soon gets traction but a tyre thread is a whole new level.

 

[greenacc]

Yes but both the 5w 40 and 10w 40 are in the safe operating range in pretty much all of Australia according to Penrite was my point. Some say you need a 5w but what's that based on? Don't say manufacturer specs because GM suggest a 5w 30 as the correct grade oil but there are too many variables, I'm sure they don't consider.

People say lots of things but most have never even seen inside an engine. 5w30 is probably good for the average daily commute in most stock cars but then again, your engine isn't stock, and Holden don't provide a 300,000km warranty to back up their recommendation so who knows what it was based on...

 

[chrisp]

Don't say manufacturer specs because GM suggest a 5w 30 as the correct grade oil but there are too many variables, I'm sure they don't consider.

I am pretty sure that GM considered a huge number of variables before they came up with their recommendations.

I find it a little bit strange that some people can underestimate, or even dismiss, the enormous amount of research and testing that manufacturers do before making their recommendations.

But feel free to try other grades in your engine, but I wouldn’t be claiming that the manufacturers haven’t considered the whole range of oil viscosities and the typical operating-temperature and cold-starting-temperatures experienced by their engines.

 

[Immortality]

Fuel Economy plays a part in the recommended oil but primarily oil weight is based on bearing clearances.

In another video that guy explains the GM Dexos spec oil and how it differs to a conventional oil including viscosity.

Well Fu, you just had to start a thread on oil. How did you think this would end?

Word of advice DO NOT start a tyre thread... An oil thread soon gets traction but a tyre thread is a whole new level.

Actually, I started the thread using a moved post from the video thread I'd made earlier but it's attributed to @Fu Manchu due to timing of the posts.

 

[vc commodore]

I am pretty sure that GM considered a huge number of variables before they came up with their recommendations.

I find it a little bit strange that some people can underestimate, or even dismiss, the enormous amount of research and testing that manufacturers do before making their recommendations.

But feel free to try other grades in your engine, but I wouldn’t be claiming that the manufacturers haven’t considered the whole range of oil viscosities and the typical operating-temperature and cold-starting-temperatures experienced by their engines.

I wouldn't take it as gospel...

Does 15,000K changes with V6 ring any bells?

So yes, try other grades for sure

 

[losh1971]

I am pretty sure that GM considered a huge number of variables before they came up with their recommendations.

By variables I mean engine component changes and high mileage.

 

[figjam]

Well Fu, you just had to start a thread on oil. How did you think this would end?

Word of advice DO NOT start a tyre thread... An oil thread soon gets traction but a tyre thread is a whole new level.

Actually, blame Mort .......... he put up the original video and wanted to know if he should star an oil thread.
I PMd him and agreed, coz I love reading controversies rather than conspiracies.