thin perhaps not as good as i thought

[Shannow]

Originally Posted By: JOD
But again, it's a false dichotomy to assume that because an oil offers better fuel economy, it must result in more engine wear. While that may have the potential to be true in some circumstances, more often the opposite is true--thinner weights result in less wear.


I've been slammed time and time again for stating that I never have claimed that thin will "destroy engines, show me the pile of failed engines" (a regular request on this site), I have maintained that the headroom is lower in terms of safety factor before things in the engine meet, and really wear.

The reduction in safety margin, in my experience, IS a reduction in protection, as there's less room for when things aren't exactly right.

Spent 10+ years looking after 4 off 200+tonne, 3,000RPM rotating assemblies on ISO 32 mineral oil, and needed to understand exactly where the limits were to ensure bearing life, frictional losses, stability (whirl and whip are not your friend), average operating temperature/viscosity, transition from hydrodynamic to stationary, and stationary to hydrodynamic...and what happens when stuff goes wrong...including designing oil lead ins, orifices, clearances, and journal shapes.

As an engineer, I needed to know the boundaries of "safe", and map where I was within those boundaries, and knowledgeably choose how close that I got.

For an OEM to reduce viscosity as a means to attain CAFE issues is a transfer of risk to the owner, pure and simple.

It's the realisation of that risk that's in question.

It's a low rate (no piles of destroyed engines).

Originally Posted By: JOD
more often the opposite is true--thinner weights result in less wear.


I'd like to see the proof of that.

 

[Shannow]

Originally Posted By: CATERHAM

With the maximum speed of oil flow through a crankshaft, up to 12 gallons per minute, the difference in oil temp's from input to out put is no where near 40-45C in most IC engines.
When oil temp's are given, it is bulk sump oil temperature that are referenced.


A bearing is a bearing, and as I have demonstrated time and time again, in bearing design, some oil circulates (in the bearing), some leaks out, and some is added as fresh make-up.

Bearing temperature rises of 20-40(+) are typical of the operating point of any bearing...it's simple physics and thermodynamics...there are pretty simple online walk throughs from most universities that can teach how bearings behave...I've linked a bunch previously.

An engine has lots of stuff happening, bearings (which behave like bearings behave, and have significant difference between bulk oil and bearing operating temperatures), oil squirters (minimal temperature rises, and direct oil based on plain old viscosity and density, not HTHS), chain oilers and tensioners, et al.

the 12 Gal doesn't have to be cooled by 40C, as the whole 12 Gal is not seeing operation in a loaded bearing.

 

[demarpaint]

Originally Posted By: MarkStock
Originally Posted By: demarpaint
As far as what I drive with a warranty. My 08 Jeep has a lifetime power train warranty.


Are you seriously telling us that with a LIFETIME warranty, you're complaining that the manufacturer wants you to use pretty much any 5w20 out there and that the government is compromising your choice? Seriously?


How's this since you know it all. Show me proof 20 grade oil is best for any and all user possibilities for my Jeep engine. You're the one making the claims one choice is best for this engine, not me. Then show me proof you're an authority. As far as skits go, I can't show you the one I found for you, I'll get tossed off the board.

As far as the Lifetime Warranty, its useless if I give them an out, a smart guy like you should know that?

Mark care to challenge this? Or all the oil choices he has in OZ for cars sold in the US which are only allowed 20 grade oil? I anxiously await your expert and authoritative reply.

Originally Posted By: Shannow


For an OEM to reduce viscosity as a means to attain CAFE issues is a transfer of risk to the owner, pure and simple.

It's the realisation of that risk that's in question.

It's a low rate (no piles of destroyed engines).

 

[MarkStock]

Originally Posted By: demarpaint
Mark care to challenge this? Or all the oil choices he has in OZ for cars sold in the US which are only allowed 20 grade oil? I anxiously await your expert and authoritative reply.

Originally Posted By: Shannow


For an OEM to reduce viscosity as a means to attain CAFE issues is a transfer of risk to the owner, pure and simple.

It's the realisation of that risk that's in question.

It's a low rate (no piles of destroyed engines).


I agree with what he says and have said as much before.

We also need to make a similar statement for those owners who only drive their vehicles before they are fully warmed up and therefore have been running thicker oil than was available and applicable for their circumstances due to manufacturer recommendation.

 

[demarpaint]

Originally Posted By: MarkStock
Originally Posted By: demarpaint
Mark care to challenge this? Or all the oil choices he has in OZ for cars sold in the US which are only allowed 20 grade oil? I anxiously await your expert and authoritative reply.

Originally Posted By: Shannow


For an OEM to reduce viscosity as a means to attain CAFE issues is a transfer of risk to the owner, pure and simple.

It's the realisation of that risk that's in question.

It's a low rate (no piles of destroyed engines).


No, I agree with what he says and have said as much before.


We're making progress. Oil choice takes some of the risk away from the owner, if he can match the oil viscosity to how the vehicle is used, and not risk warranty denial. That's the point I'm trying to make and you seem to be missing it.

 

[Shannow]

Originally Posted By: MarkStock
Originally Posted By: demarpaint
Mark care to challenge this? Or all the oil choices he has in OZ for cars sold in the US which are only allowed 20 grade oil? I anxiously await your expert and authoritative reply.

Originally Posted By: Shannow


For an OEM to reduce viscosity as a means to attain CAFE issues is a transfer of risk to the owner, pure and simple.

It's the realisation of that risk that's in question.

It's a low rate (no piles of destroyed engines).


I agree with what he says and have said as much before.

We also need to make a similar statement for those owners who only drive their vehicles before they are fully warmed up and therefore have been running thicker oil than was available and applicable for their circumstances due to manufacturer recommendation.


Where's that in the manual ?

 

[MarkStock]

Don't almost all owner manuals recommend to go gentle on throttle before the engine has warmed up?

 

[MarkStock]

Originally Posted By: demarpaint

We're making progress. Oil choice takes some of the risk away from the owner, if he can match the oil viscosity to how the vehicle is used, and not risk warranty denial. That's the point I'm trying to make and you seem to be missing it.


BITOG members are an insignificant proportion of US car owners and you and a few others are an insignificant proportion of BITOG

The fact is that 99.999999% of people do not have driving habits that are affected by having a more limited choice of oil.

We're not even certain that you do and even if you did, you could avoid having a warranty issue by putting in that thicker safer oil.

Please give us one case of a warranty failure due to running lighter oil. On this board we see FRAM filter failures, we hear of Purolator filter issues, we hear of mistakes by mechanics, we hear of owner negligence, or trouble codes.

But where are these stories where owners had a driving style incompatible with recommended viscosity and as a result a failure occurred? Doesn't "no piles of destroyed engines" from the person you are quoting suggest to you this is a non issue?

That's what you seem to be missing. You're so obsessed with the notion that someone has taken away your freedom, that you're not actually quantifying what if anything you have lost

 

[PSE]

Originally Posted By: MarkStock
Originally Posted By: demarpaint

We're making progress. Oil choice takes some of the risk away from the owner, if he can match the oil viscosity to how the vehicle is used, and not risk warranty denial. That's the point I'm trying to make and you seem to be missing it.


BITOG members are an insignificant proportion of US car owners and you and a few others are an insignificant proportion of BITOG

The fact is that 99.999999% of people do not have driving habits that are affected by having a more limited choice of oil.

We're not even certain that you do and even if you did, you could avoid having a warranty issue by putting in that thicker safer oil.

Please give us one case of a warranty failure due to running lighter oil. On this board we see FRAM filter failures, we hear of Purolator filter issues, we hear of mistakes by mechanics, we hear of owner negligence, or trouble codes.

But where are these stories where owners had a driving style incompatible with recommended viscosity and as a result a failure occurred? Doesn't "no piles of destroyed engines" from the person you are quoting suggest to you this is a non issue?

That's what you seem to be missing. You're so obsessed with the notion that someone has taken away your freedom, that you're not actually quantifying what if anything you have lost



That's awfully presumptuous to say that running an improper viscosity oil will not cause damage to your engine. I am on the side that the automotive engineers (being one myself) recommend a certain oil to prolong the life of the engine.

Furthermore, failures from improper oil choice are not typically catastrophic. It usually means cutting the life of the engine by a significant amount. How many vehicles do you see driving around with blue smoke coming from the tailpipe or withknocking/ticking noises? I would consider these lube related failures even though it's still running down the road.

 

[demarpaint]

Originally Posted By: MarkStock
Originally Posted By: demarpaint

We're making progress. Oil choice takes some of the risk away from the owner, if he can match the oil viscosity to how the vehicle is used, and not risk warranty denial. That's the point I'm trying to make and you seem to be missing it.


BITOG members are an insignificant proportion of US car owners and you and a few others are an insignificant proportion of BITOG

The fact is that 99.999999% of people do not have driving habits that are affected by having a more limited choice of oil.

We're not even certain that you do and even if you did, you could avoid having a warranty issue by putting in that thicker safer oil.

Please give us one case of a warranty failure due to running lighter oil. On this board we see FRAM filter failures, we hear of Purolator filter issues, we hear of mistakes by mechanics, we hear of owner negligence, or trouble codes.

But where are these stories where owners had a driving style incompatible with recommended viscosity and as a result a failure occurred? Doesn't "no piles of destroyed engines" from the person you are quoting suggest to you this is a non issue?

That's what you seem to be missing. You're so obsessed with the notion that someone has taken away your freedom, that you're not actually quantifying what if anything you have lost



Shannow summed it up nicely. I asked Chrysler, and now that I think about it a Ford service writer about using oil other than the 20 grade they spec and they flat out said no. I called Chrysler corporate, I skipped asking the dealer altogether.

Read what Shannow said slowly, again, maybe then you'll understand what he's saying. It seems you have difficulty comprehending what people are saying, then pick and choose small portions of what they said completely out of context to continue your battle. I stated my position more times than I can count and you're still not grasping it. Maybe you'll grasp what Shannow said instead. Here's a hint: "For an OEM to reduce viscosity as a means to attain CAFE issues is a transfer of risk to the owner, pure and simple. It's the realisation of that risk that's in question." He also said "It's a low rate (no piles of destroyed engines)." Maybe there are some people that would rather not be in that small pile of engines. Would you? Read some of Trav's comments, he's got the credentials to back up what he says too. Any real expert will tell you to One size doesn't fit all as the US car maker is leading us to believe. Any real expert will tell you to match the oil viscosity to the climate and how the vehicle is used. 20 grade oil has its purpose, I use it. One size fits all, I don't buy into it.

Your sarcasm leaves a lot to be desired. I hope you've included yourself in the group of the insignificant portion of BOTOG members. A member with less than a month here, the self proclaimed authority in that group. I'd place you on the top of the insignificant members heap. Maybe if you can prove to me you're an expert this discussion will end. The 2004 Ford article you copied and pasted isn't cutting it.

Questions for you: Your MB gives you an oil choice, which oil do you use? Why? I'm pretty sure you were capable of making the choice and you didn't need MB or the Gub'ment to make it for you.

 

[il_signore97]

Originally Posted By: CATERHAM
Originally Posted By: il_signore97
Caterham,

While I am not against thin oils by any means (there, I said it just to clear the air before I start!!!), I would like to point out a few of my own observations / thoughts.

I can agree that almost any passenger car on the road today can run on anything from 0W20 to 20W50 and live a reasonably long life. I can also agree that it is not smart to put 20W50 in a car driving across the street everyday, and that 0W20 on a race track may not be appropriate either. So, as you state, just meet the minimum oil pressure spec as listed in the service manual, right???

However, I see a few possible concerns with this. Firstly, this is not a "spec" it is a MINIMUM spec. I will use my old 2005 Nissan Altima (3.5 L V6 engine) as an example, since I have a lot of data and experience with it. The service manual clearly states that oil pressure must be HIGHER than these numbers. It says nothing about any maximum. It states rather clearly that when an engine cannot meet these minimum numbers with specified oil at full operating temperature (oil temp), then it needs an overhaul.

Using the same car with some numbers now... It states that the MIN oil pressure at full hot idle is 15 psi, and it gives a second test spec of MIN 45 psi at 2500 RPM. This obviously assumes that all healthy engines exceed these numbers on spec'd oil. With a MIN spec of 45 psi at 2500 RPM, how on earth would you not cause the oil pump to bypass at 7500 RPM??? There is no way that this could be true unless you use a 0W10 racing oil, in which case the minimum specs would not be met at the two test RPM's.

Using another vehicle, my tow vehicle (Chev Venture) has a relatively low bypass setting, and will still cause the bypass to open up at hot idle anytime above 4500 RPM. This is with a 3.1 cP HTHS synthetic oil, which is inline with what GM specs. This is also after long highway runs with my trailer, often engaging and remaining in 3rd gear to climb long uphill passes. 270,000 km so far and runs well.

My friend's Mercedes S500 with the spec'd 0W40 always went into bypass about 2500 RPM prior to hitting redline even after long highway runs, and this vehicle is equipped with a very large oil to water heat exchanger which maintains the oil temp at 90C once warmed up (it will make its way to 100+ C on the highway but returns to 90C with a bit of idling). This car has about 340,000 km on it at this point btw.

Are you suggesting that all of these vehicles that routinely enter oil pump bypass in daily use are not using the correct lubricant? Do you honestly think that the engineers that designed these engines don't know that they will enter pump bypass during normal operation? Ultimately, do you think that they did not already take that into account and ensure that the engine, despite being in bypass, still has ample flow of oil (i.e. more than the min required for proper lubrication, even though bypass is active)?

I can't say with any certaintly, but then again, neither can anyone else unless they happen to work on the engine development teams of a major manufacturer.



Some good questions.
Those OP spec's sound about right for the Nissan but OP doesn't increase linearly with many engines. OP tends to rise rapidly and then rises a lower rate past a certain relatively low rpm.
Having said that the by-pass point is quite high on some Nissan like 120 psi.

Some GM engines have relatively low by-pass settings like 65 psi, but with the spec' 3.1 cP oil you will still be below that level at normal operating temp's. Your maximum hot OP should be in the 50s psi at elevated rev's.

I'm not as familiar with Merc' engines other than most of their factory OP gauges are pegged at 3 bar.

I'm not aware of any engines that are designed to run with their oil pump's in by-pass mode on the spec' oil grade and as yet I've never encountered one.
Understanding fully the operation of an OP gauge for a given application can take some time.




The service manual for my Nissan states that the bypass should be fully opened by 85 psi, thus, my engine did not have a higher than typical bypass value.

I believe you and I have discussed the low GM bypass settings before in a different thread some time ago, but it stands even more so that with a low bypass setting, the engine has a much greater chance of seeing bypass in regular operation. My point is that this seems to be inherent to the design, yet does not adversely affect engine life or operation.

The Benz factory oil pressure gauges are accurate, but they do peg at 3 bar after 2,000 RPM or so due to the fact that 3 bar is only 44 psi. It would stand that the actual oil pressure above ~2,000 RPM is higher than 44 psi, especially on the spec'd oil (> 3.5 cP HTHS).

Regarding understanding the operation of an oil pressure gauge in a lubrication system, it really is not much more complicated than it sounds. I can read an oil pressure gauge just as anyone else can, and when it stops rising at (or approx around) the bypass setting, the engine is most probably in full bypass. I agree the gauge rises less linearly with RPM as you get into the higher rev ranges. I can say that no mechanical bypass valve is perfectly accurate, and they do not typically open up all at once. They can begin to crack opened and gradually open further at readings lower than their actual set point. This can contribute to the non linearity of the oil pressure readings at higher RPMs. Furthermore, a lot of factory bypass valves on normal passenger cars are not large enough to accommodate a lot of flow of thick oil, especially oil thicker than normal due to lower oil temp or using thicker grade of oil than spec'd. This can actually allow the oil pressure to rise above the bypass setting, even though the bypass valve is fully opened (thus increasing the max flow of oil into the engine in that situation). When looking solely at the oil pressure gauge without knowing the bypass specs for your vehicle, you would not be able to detect these anomalies.

I still state that some, if not a good number of vehicles will run into bypass at normal oil temps with spec'd oil at higher RPMs, and as long as the flow rate within the engine is higher than the minimum required, I don't believe this poses a problem (other than unnecessary pumping losses).

 

[il_signore97]

Originally Posted By: Shannow

An engine has lots of stuff happening, bearings (which behave like bearings behave, and have significant difference between bulk oil and bearing operating temperatures), oil squirters (minimal temperature rises, and direct oil based on plain old viscosity and density, not HTHS), chain oilers and tensioners, et al.



This is something I think we all forget from time to time. Thanks for posting the reminder

An engine is not just a bunch of hydrodynamic journal bearings. While we can use an oil pressure gauge to determine back pressure as a result of proper bearing operation, the OP gauge will not tell us the size of the oil film generated between the piston rings and the cylinder walls -- an equally important part of an IC engine.

 

[JOD]

Originally Posted By: Shannow

Originally Posted By: JOD
more often the opposite is true--thinner weights result in less wear.


I'd like to see the proof of that.


you're kidding, right? practically every published study on bearing wear shows the lowest wear rates for hths in the range of 2.6 to 2.8. The studies have been posted on here numerous times, including in this thread. No, that doesn't mean that a small amount of increased wear is going to "destroy anyone's engine", but it's still true.

I'm having deja vu all over again... LINK TO THE SAME THREAD...

I'm sorry, simply disagree on your thoughts of "transferring risk to the owner" business, at least in practical terms. What risk? It's not a strawman argument to ask for examples of failures in the field as and example of this risk? There are certainly other strategies in place to deal with massive overheating which would put viscosity out of acceptable range (my car would go into limp mode well before that ever happens). And of course in Dermapaint's question, I'm really confused since the manufacturer has warrantied the engine for life? Obviously, there's no risk transferred to him...

 

[Volvohead]

Originally Posted By: Shannow
An engine has lots of stuff happening, bearings (which behave like bearings behave, and have significant difference between bulk oil and bearing operating temperatures), oil squirters (minimal temperature rises, and direct oil based on plain old viscosity and density, not HTHS), chain oilers and tensioners, et al.


You're getting at the root of it, Shannow.

Anyone who thinks they can Carnac the entire internal engine operating environment better than the manufacturer's design team did, with just a couple of fluid gauges tacked to the A pillar, is running with blinders on.

It's a very complex environment indeed.

 

[JOD]

Originally Posted By: il_signore97
Originally Posted By: Shannow

An engine has lots of stuff happening, bearings (which behave like bearings behave, and have significant difference between bulk oil and bearing operating temperatures), oil squirters (minimal temperature rises, and direct oil based on plain old viscosity and density, not HTHS), chain oilers and tensioners, et al.



This is something I think we all forget from time to time. Thanks for posting the reminder

An engine is not just a bunch of hydrodynamic journal bearings. While we can use an oil pressure gauge to determine back pressure as a result of proper bearing operation, the OP gauge will not tell us the size of the oil film generated between the piston rings and the cylinder walls -- an equally important part of an IC engine.


That's certainly true. It's also been demonstrated that lighter weight viscosity oils provide thicker film mid-stroke at the top of the piston, and the reality this is probably more important in terms of wear.

 

[HerrStig]

I'm still waiting for a rational explanation of why oil reccomendations for the SAME car can vary by country.

 

[demarpaint]

Originally Posted By: HerrStig
I'm still waiting for a rational explanation of why oil reccomendations for the SAME car can vary by country.


I'd love to hear the rational explanation myself. The best I can tell you is CAFE is behind what's used in the USA.

 

[JOD]

Originally Posted By: HerrStig
I'm still waiting for a rational explanation of why oil reccomendations for the SAME car can vary by country.


Why, when it's been explained a million times? different operating conditions, limited distribution of 20W ois, consumer perceptions, longer specified drains, government regulations (some countries had lower limits of 3.5 hths until fairly recently).

I'm still waiting for a rational explanation as to why it matters to someone operating their car in the U.S.?

 

[CATERHAM]

Originally Posted By: il_signore97

An engine has lots of stuff happening, bearings (which behave like bearings behave, and have significant difference between bulk oil and bearing operating temperatures), oil squirters (minimal temperature rises, and direct oil based on plain old viscosity and density, not HTHS), chain oilers and tensioners, et al.

An OP gauge is an effective viscometer. If you know for example that 60 psi at elevated rev's represents a safe operational viscosity for a particular engine that's all you need to know.
That fact that oil temp's will vary in different parts of an engine is interesting stuff but is immaterial to what one really wants to know; namely, how light an oil grade or more precisely, what's the lowest combination of HTHSV and VI that I can run without issue in my engine.

So if you can maintain the required minimum OP on a 2.6cP 200 VI 0W-20 oil in your climate and with the way you operate your vehicle then that's the heaviest grade you need to run regardless of what oil grades are listed or recommended for that engine.

Having said that, most members here don't have an OP gauge or even an oil temp' gauge so short of borrowing the experience of someone who does for your particular engine you must rely on what the manufacturer recommends. And most would agree, running the lightest recommended oil grade will more than meet the viscosity demands of the engine plus a substantial safely margin. Heavier alternate oil grades may be mentioned for warmer climates or higher ambient temp's but that doesn't detract in any way that the lightest oil recommended is usually the preferred choice.

 

[buster]

Originally Posted By: JOD
Originally Posted By: HerrStig
I'm still waiting for a rational explanation of why oil reccomendations for the SAME car can vary by country.


Why, when it's been explained a million times? different operating conditions, limited distribution of 20W ois, consumer perceptions, longer specified drains, government regulations (some countries had lower limits of 3.5 hths until fairly recently).

I'm still waiting for a rational explanation as to why it matters to someone operating their car in the U.S.?



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