Automotive engineers and oil

[JW_Ford]

Originally Posted By: Inspecktor
If there was no CAFE, would we see any 20 wt oil on the market?


If there was no CAFE and vehicles still had variable cam timing and cylinder deactivation then yes there would be 20 wt oil.

 

[friendly_jacek]

Originally Posted By: Nick1994
I believe they do design an engine around 0w20, that's what almost all the cars are getting now except for German cars.


id they decide to design a fuel efficient gasoline engine (and they do that often as you noticed), low viscosity lubricants would be a part of the design.

 

[TFB1]

Originally Posted By: JW_Ford
Originally Posted By: Inspecktor
If there was no CAFE, would we see any 20 wt oil on the market?


If there was no CAFE and vehicles still had variable cam timing and cylinder deactivation then yes there would be 20 wt oil.

Well I'll never believe that, maybe 0/5W-30...

Been several posts here where someone used 5/10W-30/40 oils and VVT was not adversely affected...

In Costa Rica the dealers are using 20W-50 oil in three valve 5.4 Fords(was posted earlier this week)...

 

[JW_Ford]

Originally Posted By: TFB1
Originally Posted By: JW_Ford
Originally Posted By: Inspecktor
If there was no CAFE, would we see any 20 wt oil on the market?


If there was no CAFE and vehicles still had variable cam timing and cylinder deactivation then yes there would be 20 wt oil.

Well I'll never believe that, maybe 0/5W-30...

Been several posts here where someone used 5/10W-30/40 oils and VVT was not adversely affected...

In Costa Rica the dealers are using 20W-50 oil in three valve 5.4 Fords(was posted earlier this week)...


30w is fine its just not what they would recommend probably. GM finally switched to 0w-20w in there 1500 trucks and they were meeting CAFE just fine before. I would think using 20w-50 oil in a three valve 5.4 would cause some phaser problems if using the wrong oil filter could.

 

[d00df00d]

Originally Posted By: Moondawg
It has been stated several times on BITOG, that a car/truck manufactures engineers know what is the best weight engine oil for a particular engine and that is why they spec that weight in the owners manual. Is this always true?

Is it true that they know? Yes.

Is it true that that knowledge always drives the spec in the owner's manual? No. The owner's manual spec comes from some combination of engineers, bean counters, PR people, etc.


Originally Posted By: Moondawg
Do the manufactures and engineers really design an engine around one or at most two particular weights of engine oil?

It'd be more true to say they design around a spec rather than a weight. But yeah, I'm sure they do, especially in cases where the company wants as many of their cars as possible to be able to run the same oil spec (e.g. most BMWs run LL-01, most Mercedes-Benzes run MB 229.5, etc.).

In some cases, the engine and the oil are developed in parallel, e.g. BMW M engines and Castrol TWS.

 

[stchman]

The thing that gets me, people on BITOG come here and think they know more about the engine in their car than the person who designed it.

The truth is, if one uses the recommended viscosity and follows the manufacturer's recommendations for a maintenance schedule, the engine will far outlast the body.

 

[Joe90_guy]

You have far more faith in human nature than I do.

I was once in a meeting discussing Renault's 18,000 mile drain interval. 18,000 miles, even on a decent synthetic, is a big stretch. So I get told, 'We know that some engines will fail before 18,000. But this means only one oil drain in two years which is great for 2 year B2B rentals. We have computed the odds on some engines blowing up and it works out better for us if we simply replace the failed engines, free-of-charge, and keep the savings from lower maintenance over two years'.

Still think it's always better to follow the OEMs recommendations?

 

[BrocLuno]

ROI, it's built in to engineering. Life expectancy is defined as keeping the CAT's alive 100,000 miles.

Every engineer knows how to calculate odds and failure curves and predict "acceptable" failure rates vs cost of manufacturing. If the OEM is picking up the cost of "free maintenance", then that is factored in too...

Renault has french engineers ... They are bit different, but not bad, and they get the same classes and requirements as others.

Oils have to do a lot of jobs besides just lubricate. They are the engines internal cooling fluid. They are the flushing fluid and activation fluid for various devices. They have to keep foreign materials in suspension until they can be filtered. They have to neutralize combustion gas by-products...

They have to reduce friction including internally in bearing spaces (oil as source of heat based on resistance). You'all have been around hydraulic systems that get very hot w/o any combustion at all (we hope).

So why an oil class is chosen is based on a whole lot of factors. It's the bottom line in their analysis. And lubrication engineers are a specialty, not a default dunce cap job.

The recall potential to bankrupt a company based on engine (or other component) failures makes sure that many eyes have seen the list of oil choices and have signed off on meeting the requirements. CAFE is just one small factor in the decision tree...

 

[Oregoonian]

Originally Posted By: JW_Ford
440Magnum you are absolutely correct.


+2.....great explination and I agree with you completely.

 

[pdxglocker9mm]

"If engineers were allowed to design and build exactly what they thought was a great car it would certainly be a lot different from the one that gets produced. And if produced this wonderful car would probably be the end of the manufacturer." OneEyeJack


I highly doubt that, if you have ever worked with a product thru beta testing then full retail roll out you would know your statement is incorrect. The engineers are smart but you can't fix stupid or even engineer out stupid. People think of ways to mess things up. Fix one way they WILL find another. I saw a engineer write a 55 page manual on theory operation and safe handling for a product because the managers asked him to do it. He should have had it Printed on toilet paper because that is the most constructive thing the workers would have done with it.
On another occasion I went rounds with an engineer because the unit in question "is highly accurate" and "it can't do that" well buddy I don't care if you wear a funny hat and are qualified to drive a train.
This customer used your product in "x" fashion which is per your instructions BTW and this is the result.
Bottom line for a successful product
Engineering with feedback from consumers and those who are paid to diagnose and repair the unit
If you can't service the product and repair it for the customer cost effectively you have lost before you even started.
It's a delicate balance but sometimes you just need to cut it and try it.

 

[kschachn]

Originally Posted By: pdxglocker9mm
I highly doubt that, if you have ever worked with a product thru beta testing then full retail roll out you would know your statement is incorrect. The engineers are smart but you can't fix stupid or even engineer out stupid. People think of ways to mess things up. Fix one way they WILL find another. I saw a engineer write a 55 page manual on theory operation and safe handling for a product because the managers asked him to do it. He should have had it Printed on toilet paper because that is the most constructive thing the workers would have done with it.
On another occasion I went rounds with an engineer because the unit in question "is highly accurate" and "it can't do that" well buddy I don't care if you wear a funny hat and are qualified to drive a train.
This customer used your product in "x" fashion which is per your instructions BTW and this is the result.
Bottom line for a successful product
Engineering with feedback from consumers and those who are paid to diagnose and repair the unit
If you can't service the product and repair it for the customer cost effectively you have lost before you even started.
It's a delicate balance but sometimes you just need to cut it and try it.


Hey, thanks for joining just to bring us that.

 

[Greasymechtech]

Greatest automotive designer of all:

 

[440Magnum]

Originally Posted By: friendly_jacek
Originally Posted By: Moondawg
It has been stated several times on BITOG, that a car/truck manufactures engineers know what is the best weight engine oil for a particular engine and that is why they spec that weight in the owners manual. Is this always true?


if it's true why the toyota's 2GR-FE engine is specified for 5W30 or 5W20 oils (depending on year or car) in US, while outside US, 10W30 is the thinnest oil, allowed only during cold winters and 5W40 and up cover summer temps?


People always drag that dead horse up when this topic comes up, and the implicit assumption is that its because of CAFE requirements.

Maybe that plays into it... but then its JUST AS LIKELY that Xw20 oils are better suited to these engines, but if they spec'd such an oil for areas outside the US where Xw20 oils are rare as hen's teeth, people there would more likely buy cars that didn't need "hard to find and exotic oil."

 

[CT8]

XW-20 is Cafe .

 

[shDK]

How Come People here seem to believe vvt works Best With thin oil.? I ovn a renault With a engine well known for Cam dephaser problems. It is also known That a 5w-40 oil is better for the dephaser then 5w-30. The car runs 30.000 km oci.

 

[Jetronic]

you might consider reducing the oci, if you read this thread...

 

[hatt]

Originally Posted By: stchman


The truth is, if one uses the recommended viscosity and follows the manufacturer's recommendations for a maintenance schedule, the engine will far outlast the body.
Plenty of 20+ year old work trucks running around here. I wonder how many are on the factory engine. The engine outlasting the body may be relevant in the rust belt, but not everywhere with every vehicle.

 

[BrocLuno]

+1

We have every age car here. The reason to toss them is because they won't pass SMOG Testing. Or can't be cost effectively repaired to do so ...

1975'ish and before are pretty much exempt, so they are prized, and are usually on their third or fourth engine by now ...

Old work trucks going back to the 1960's are not all that hard to find. I gave my 1955 Ford F-2 to the boy a few years back and it was only on engine #2 (engine #1 - 223 six with 188K when it died...)

 

[Shannow]

Originally Posted By: KGMtech
Originally Posted By: Inspecktor
If there was no CAFE, would we see any 20 wt oil on the market?


Good question, but necessity is the mother of invention. I think we all benefit from the CAFE requirements - engineers work better with challenges - excepting some VW examples.


If you didn't have CAFE before, you would/will have carbon. That's the "CAFE" that everyone else in the world is working under.

I agree with KGMtech that things like this drive innovation that wouldn't have occurred naturally...if you read the CAFE papers, they make a statement that consumer undervalue economy by a factor of "4" in their vehicle buying choices, so a framework was introduced to drive that focus through other channels.

They also state that engine oil is the least cost modification that an OEM can do to reduce fuel consumption, in terms of passing costs on to consumers.

 

[Shannow]

Originally Posted By: MolaKule
IN terms of engine engineers, I would say that according to the laws and constraints (EPA and lawyers) they work under, yes.


Even industrially we have to work around evolving legislation.

Best mill ring and pinion gear lube was always "Mobiltac E", but the solvent was nasty, and it's been phased out.

Replacements are much, much more expensive, and more "finnicky"

Originally Posted By: MolaKule
I really have my doubts about manual transmission and differential engineers. They seem to know their ME theory but often lack in lubrication knowledge.


Yep, I was good at the gearbox (industrial) theory when it comes to oil selection and application (*), but that theory clearly does not work in differentials...or they simply wouldn't last.

I've given up trying to "design" the lubes for my diffs, and take recommendation from what works.

(*) gearbox oils are a pain at the moment in Oz, ISO 1000 is becoming 450cst within weeks, but the oil manufacturers are claiming that they are not bolstering lower grade lubes with polymers...I'm struggling to believe them