Question about the cSt of oil

[CATERHAM]

Originally Posted By: d00df00d
Originally Posted By: ARCOgraphite
Originally Posted By: CATERHAM


... HTHS viscosity is the accurate measure of how "thick" an oil is, not the kinematic viscosity spec' your looking at.
M1's 10W-30 not surprisingly has a higher HTHS vis than for their 5W-30 grade and therefore is the more viscous at normal operating temp's and higher.
...

I tried to explain that to my oil pump during a -10F cold start and it just went, "grunt ... Grunt"

Sorry, CATERHAM. He's got you there. HTHS is an important spec but it's no more "accurate" than kinematic viscosity.


I'm talking about viscosity at operating temp's, I don't know what ARCOgraphite is talking about.

HTHS vis correlates very well with operational viscosity, the KV100 spec' does not. The following thread explains it in more detail:

https://bobistheoilguy.com/forums/posts/2018835/

 

[d00df00d]

You and I both know that how an oil performs at operating temp is only part of the story, no?

Besides, I'm pretty sure the OP wasn't intentionally confining the inquiry to operating temps -- or at least, they wouldn't have done so if they knew performance at other temps was important. Hope the OP will correct me if I'm wrong on that.

 

[Doug Hillary]

Hi,
sometimes Threads seem to get lost but the "operating temperature" of the oil is an interesting topic within this one!

It is common to have the bulk oil temperature at around 90C or so in many engines. This means for instance that the SAE40 oil in the pan is actually at around SAE50 viscosity

 

[illby1]

Originally Posted By: d00df00d
You and I both know that how an oil performs at operating temp is only part of the story, no?

Besides, I'm pretty sure the OP wasn't intentionally confining the inquiry to operating temps -- or at least, they wouldn't have done so if they knew performance at other temps was important. Hope the OP will correct me if I'm wrong on that.


Being a "new" guy to this forum, I guess I was/am confused trying to find the "perfect" oil for my car... I was under the impression that at operating temp that 10cSt was the "magic" number that I was looking to get,I guess I was wrong. If I understand correctly,a 0W or 5W oil will be a better at start up (where most wear occurs) I know that there are MANY different opinions and there may not BE a "perfect" oil. I am looking for some knowledge from you guys as to which oil would be better than others...

Thanks!!
Scotty B

 

[jorton]

Originally Posted By: illby1

3. Northern Wisconsin
4. 4 mile commute to work,longer trips on the weekends
5. Mostly short trips to and from work and errands...Longer road trips on the weekends


Originally Posted By: Doug Hillary
Hi,
sometimes Threads seem to get lost but the "operating temperature" of the oil is an interesting topic within this one!

It is common to have the bulk oil temperature at around 90C or so in many engines. This means for instance that the SAE40 oil in the pan is actually at around SAE50 viscosity


So your 8.5cst Mobil 1 0w-20 will be much more than 10cst most of the time.

Check Havoline Deposit Shield specs.

 

[illby1]

Thanks for the opinions. I think I will go with the Valvoline and run it 5-6,000 miles and see how it does.

Scotty B

 

[demarpaint]

Originally Posted By: Doug Hillary
Hi,
sometimes Threads seem to get lost but the "operating temperature" of the oil is an interesting topic within this one!

It is common to have the bulk oil temperature at around 90C or so in many engines. This means for instance that the SAE40 oil in the pan is actually at around SAE50 viscosity


Great point Doug, so that would make a 20 grade oil close to if not a 30 grade in some engines. Stepping up to a 30 grade in an engine calling for a 20 grade might not yeild the results many people think they're getting by making the change. Especially in an engine that has no issues, or during the colder months of the year. That for me makes a better case to stick to what the mfg suggests. I'm sure your point was and has been taken into consideration when an oil is spec'd. JMO

 

[Jim Allen]

Yeah, that's why having an oil temp gauge could be considered a vital tool for anyone daring to second guess the engineers. Or perhaps to spot check their work. In reality, oil temp variations are probably very different among all vehicles in the various climates and the OE has to shotgun the recommendations, perhaps offering exceptions in the manual.

My 5.4L Ford seldom exceeds 200F, and never by much, even in the summer and at work, so my 5W20 is usually running as a 30 grade. A guy down in "Fry -an-egg on-the-sidewalk," Texas, may be running well over 212F and his KV may be at the low end of the grade, maybe even out of grade. I will caution to say that doesn't seem to be the case with the 5.4L but it could happen on any engine intheory, and that's what we are all about.

To the OP; forgive us hijacking your basic question to debate the fine points and hiding your answer in the minutae we love to pedantically discuss.

 

[illby1]

You are forgiven..... ;o)

 

[mechtech2]

Jim Allen -
Sometimes engineers are overridden.
What is perfect and best may not be recommended.
Cheap and light ATF for trannys. Various mandated oils for the engine, too. [Low on necessary additives or viscosity.]

Make it smaller, cheaper, lighter. Not make it best.

 

[Jim Allen]

Originally Posted By: mechtech2
Jim Allen -
Sometimes engineers are overridden.
What is perfect and best may not be recommended.
Cheap and light ATF for trannys. Various mandated oils for the engine, too. [Low on necessary additives or viscosity.]

Make it smaller, cheaper, lighter. Not make it best.


Item one: Seldom happens according my sources, which are considerable in the auto industry, but the potential is there... acknowledged. Skimping is done usually after the most careful engineering reviews.

Item Two: NOTHING is "perfect." "Best" is hard to pin down and highly variable.

Item Three: Perhaps, but you can look at it in other ways too... such as conservation of resources, reducing consumer price, etc.

Item Four: Don't know about you, but I can't afford the best. If I could, I'd be driving a Maybach, a Rolls or a Ferrari (assuming they can be called "best," I honest don't know how to define best). I choose the "best" of what I can afford, defined by me and my wallet.

There's got to be a certain amount of profit for the manufacturer of anything, for everything from gold plated faucets in the CEO's private bathroom to the (hopefully fair) wages for the guy sweeping the floors. Free market competition is the price equalizer that generally averages things out. Something gets too expensive, people quit buying it. The company adjusts or dies. A company gets too greedy with wages and such, they have trouble. They adjust or die. I think we generally get pretty much what we pay for and there are few "evil conspiracies."

 

[Doug Hillary]

Hi,
Jim - ME in the Auto Industry suggests much the same as you have written

Engineers are listened to as the warranty implications are very real - and very costly

IME Manufacturers (Euro) offer real alternatives to a FF and these must be avaialbe and not "theoretically" available. As a MB Engineer pointed out to me at Unterturkheim last year - "many people waste a lot of money on exotic oils when any Approved product will do the job very well" (rough translation)

Cost effectiveness in production is a critical pint and it is true that shortcuts are/have been taken no doubt - but these usuall come back in buyer dissatisfaction or under Warranty

It takes time to change a component in production. The Japanese have been the best I've see - starting 30 years ago! Others (German) are usually so cautious that they will wear Warranty until the appropriate "fix" is in place

The worst for me was with BMC in the 1960s. Some issues with the Mini were never rectified. Gearbox items were stolen off newly manufacturered cars to satify Warranty needs. It was sometimes years just to recify "simple" matters. With Leyland - I have been in Meetings where the Engineers cried as there was no money to develop excllent basic designs that were already in production with serious faults!

Recent experience in Germany for me - at the highest Engineering levels - suggest that development delays are still occurring though some is contracted out. And, some "global" issues are still awaiting a "fix"

IME lubricanst were never such a big deal one Approvals were achieved and specification or product updating processes determined