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Millers oil 10-50.....here we go again

Frankyboy

Monza
Joined
26 Feb 2018
Messages
152
Ok guys recently done an oil change on the 997 using Millers 10-50 Nt+ and K&N Oil filter I probably let it drain for a good 20mins ...bit of confusion as to how much oil they take as the oil sump apparently can hold up to a litre of oil...

So I put in exactly 7.5litres and once warmed up and fully cooled down I've found the oil measurement gauge on the dash shows slap bang in the middle so I'm happy with that..my point is since the oil change my oil temp gauge when fully warmed up is now reading 100 instead of the usual 90..

Any you guys encountered similar?...
 
I would guess at the viscosity assuming it had 0/40 in it before ..

I often see temps at 100 or above though on a tester with a hot idling engine regardless of the oil type .
 
I had Mobil previously and switched to Millers at the last oil change - oil temp still at 90 at operating temp - it only gets to 100 when I'm in London traffic.
 
The oil should flow as much as possible. One of the purposes of the oil is to cool vital parts in the engine. With thick oil, there will be more resistance in the oil pump, and the oil will not flow through the engine at the speed the engine is designed for. You should use as thin oil as possible, but of course so thick that the oil pressure is maintained and the engine does not use too much oil. If the engine does not have internal wear, it is completely wrong to use oil outside the A40 specifications. 10w50 is guaranteed not to be A40. The viscosity of the oil has nothing to do with oil film strength. The additive package takes care of that. Liquid can not be compressed no matter how thin or thick it is. As long as you have oil pressure, you are safe. A 0w40 will flow almost twice as fast to vital engine parts at cold start compared to 10w50. And remember that 70-80% of engine wear occurs at cold starts. Therefore important with fast flowing oil with good additive package.
 
Martini Turbo said:
The oil should flow as much as possible. One of the purposes of the oil is to cool vital parts in the engine. With thick oil, there will be more resistance in the oil pump, and the oil will not flow through the engine at the speed the engine is designed for. You should use as thin oil as possible, but of course so thick that the oil pressure is maintained and the engine does not use too much oil. If the engine does not have internal wear, it is completely wrong to use oil outside the A40 specifications. 10w50 is guaranteed not to be A40. The viscosity of the oil has nothing to do with oil film strength. The additive package takes care of that. Liquid can not be compressed no matter how thin or thick it is. As long as you have oil pressure, you are safe. A 0w40 will flow almost twice as fast to vital engine parts at cold start compared to 10w50. And remember that 70-80% of engine wear occurs at cold starts. Therefore important with fast flowing oil with good additive package.

Very good explanation sir. :thumb:
 
Apart from the fact that Hartech recommend 10w50 millers in M96/7 engines and all the GT3 specialists use 10w60 in GT3s.

As always, everyone has an opinion. :grin:

I think I'd rather have more hot protection than cold. It's cold for a few mins. It's hot for the remainder of any journey. Which in my case could be another 10 hours depending on what I'm upto.

And let's face it if a 10 grade oil wasn't sufficient to lube things correctly on a cold start, we'd have a lot of engine failures being posted on the internet.
 
Would a 5w50 be better?
Lighter weight than the 10w for cold flow
 
isnt cold when the bore scoring is mostly done?
 
Marky911 said:
Apart from the fact that Hartech recommend 10w50 millers in M96/7 engines and all the GT3 specialists use 10w60 in GT3s.

As always, everyone has an opinion. :grin:

I think I'd rather have more hot protection than cold. It's cold for a few mins. It's hot for the remainder of any journey. Which in my case could be another 10 hours depending on what I'm upto.

And let's face it if a 10 grade oil wasn't sufficient to lube things correctly on a cold start, we'd have a lot of engine failures being posted on the internet.


Yes this explanation is the correct one , the flat 6 engine and the way it retains oil when cold and the hot spots it creates mean you cannot apply usual engine science to it . So listen to the specialists who know these cars better than anyone. :thumb:
 
Martini Turbo said:
The viscosity of the oil has nothing to do with oil film strength.

Not true, the oil film strength increases linearly with viscosity. If the viscosity doubles the oil film strength doubles and double the load will be supported before metal to metal contact occurs. It has nothing to do with all oils being incompressible. The oil film is not operating in an enclosed space so it is the oils viscosity combined with relative movement of the components it is keeping apart which provides the load bearing properties.
 
Martini Turbo said:
The oil should flow as much as possible. One of the purposes of the oil is to cool vital parts in the engine. With thick oil, there will be more resistance in the oil pump, and the oil will not flow through the engine at the speed the engine is designed for. You should use as thin oil as possible, but of course so thick that the oil pressure is maintained and the engine does not use too much oil. If the engine does not have internal wear, it is completely wrong to use oil outside the A40 specifications. 10w50 is guaranteed not to be A40. The viscosity of the oil has nothing to do with oil film strength. The additive package takes care of that. Liquid can not be compressed no matter how thin or thick it is. As long as you have oil pressure, you are safe. A 0w40 will flow almost twice as fast to vital engine parts at cold start compared to 10w50. And remember that 70-80% of engine wear occurs at cold starts. Therefore important with fast flowing oil with good additive package.

Pedant alert (from scientist) - you can compress liquids, including oils, but not very much, and it requires high pressures. How much depends on the liquid (coefficient of compressibility).
Sorry, I will leave now....
 
drmark said:
Pedant alert (from scientist) - you can compress liquids, including oils, but not very much, and it requires high pressures. How much depends on the liquid (coefficient of compressibility).
Sorry, I will leave now....


Can i just ask for my own interests please ... brake fluid would have a higher compression than the system would generate before it could compress ? and if not are we talking Microns of compressibility ?

Is it density related ?

System pressure .. hmm let's go with 50 bar as i have seen that reading .

I know moisture can cause air with heat hence we change the fluid every few years but i am interested in the rates of fluid compression .
 
deMort said:
drmark said:
Pedant alert (from scientist) - you can compress liquids, including oils, but not very much, and it requires high pressures. How much depends on the liquid (coefficient of compressibility).
Sorry, I will leave now....


Can i just ask for my own interests please ... brake fluid would have a higher compression than the system would generate before it could compress ? and if not are we talking Microns of compressibility ?

Is it density related ?

System pressure .. hmm let's go with 50 bar as i have seen that reading .

I know moisture can cause air with heat hence we change the fluid every few years but i am interested in the rates of fluid compression .

There is no such thing as a perfect fluid (not least due due to impurities) so all compressible but, unless significant water content (which turns to compressible steam rather than air when heated), only by tiny amounts. I was being a pedant.
 

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