Optimal kinematic viscosity for mimimal wear?

[OVERKILL]

Originally Posted By: CATERHAM
Measuring boundary lubrication friction of valve train shims at very low rpm's may be interesting but falls far short of the entire picture of engine wear as a whole.

UOA measures engine wear in its totality.



And a snippet from Doug's article:

Originally Posted By: Doug Hillary

By Doug Hillary

UOAs are a great tool in the Management of any machinery that uses liquid lubricants. Unfortunately, their real value is often misunderstood by those who contribute to BITOG.

Firstly, it is important to realize that you get what you pay for. The most common forms of UOA are limited in their scope. It is a case of if you pay more you get more. So my comments here relate primarily to the “simple” UOAs – the cornerstone of those appearing on BITOG

Secondly, it is easy to assume that by carrying out a UOA you will be able to determine how quickly the engine is wearing out. As well, if you change lubricant Brands you will be able to compare the wear metal uptake results and then make a balanced best lubricant choice to make your engine last longer.

Sadly that logic is seriously flawed.

Single pass (random) UOAs will provide some information regarding wear metals but unless you have a history of your engine’s performance up to around 1 million miles the results are simply that – UOA results! As an example a limit of 150ppm of Iron is a reality – after say 100k it means the lubricant should be changed and all is well. But what is the situation if you have 150ppm of Iron at 5k? Where would you look what would or could you do? So UOAs are really a diagnostic tool – one of many!

The other parts of the UOA Report will be much more valuable to you – it will tell you about the CONDITION of the lubricant and its suitability for further use. This will enable you to get the maximum safe use from the lubricant saving a valuable resource in the process.


And another little part worth mentioning from the article:
Originally Posted By: Doug Hillary
During the last 50 or so years I have carried out hundreds of UOAs on all sorts of engine configurations – and on transmissions, gearboxes and differentials. These were done in consort with four Major Oil Companies (Shell, Exxon-Mobil, Castrol, Chevron-Caltex), my Employers, my Customers and on my own Fleet and other vehicles. Not once were they ever used to discriminate one lubricant from another on the grounds of wear metal uptake!

 

[BuickGN]

Originally Posted By: ekpolk
Originally Posted By: BuickGN

I've had two engines self destruct with oil that looked like glitter yet still manage to have ok UOAs. Personally I believe my own teardowns over UOAs.

Perhaps if you had used a lower viscosity oil. . . Couldn't resist that bait.

No worries, I was wondering which one of you (thin guys) were going to say that.

You could make an argument that smaller wear particles come about when an oil is protecting well and there's very little wear. And large particles come about when a lot of wear is taking place.

When my oil looked like glitter, I assume if I can see it with my eyes it's way too large to be picked up with a UOA. Most wear metals were in the single digits and it was so bad I should've recycled the oil for it's metal content lol. What would your conclusion be when 3 UOAs showed everything was fine even though you're staring at the pretty sparkly oil, tear it down and see the rods and mains worn nearly to the backing, a big wear ridge on the cylinders, and the rings so worn that you can tell just from eyeballng them form a distance. I could actually feel that they were lighter which is something you usually can't tell in an engine that has gone half a million miles.

 

[BuickGN]

Originally Posted By: CATERHAM
Originally Posted By: Junior
Originally Posted By: BuickGN


I guess what I'm looking for is an admission that higher power outputs regardless of temperature require higher viscosities to keep things separated.


In general for a given bearing, higher loading or lower RPM will require a higher viscosity. But the viscosity selected has to take into account the actual operational conditions and physical size of the bearing. For example, and F1 engine has a high specific power output per liter but I have read they use low viscosity oils. Of course they spin 19,000 rpm and are not a fair comparison when speaking in terms of passenger car engines.

The point is, viscosity is selected based on the application not just the power output alone.



+1 F1 engines use 5 wt and 10 wt oils. It was the advances in engine lubrication technology back in the 80's and 90's that led to the rev's peaking at 21,000 and even 22,000 rpm. Unfortunately the technological development has been capped and the rev's are now limited to 18,000 rpm. They still sound sweet though!


You don't know what they use for a fact so don't post opinions as such.

I get condemned for posting my "race engine" results in the GN with my stock clearances and production parts using a thick oil to survive yet it's ok for you guys to mention Top Fuel and F1. And consider that valide. Here's a question, how much torque do F1 cars make?? You may find you answer in there.

 

[FZ1]

You're breakin' that car too much! You need to get some tires with less rear traction so you can spin them more easily and,therefore, take the strain off you engine and drive train. Then it won't break so often.

 

[SuperBusa]

Originally Posted By: BuickGN

I get condemned for posting my "race engine" results in the GN with my stock clearances and production parts using a thick oil to survive yet it's ok for you guys to mention Top Fuel and F1. And consider that valide. Here's a question, how much torque do F1 cars make?? You may find you answer in there.


Good question ... and yes, that's a factor. Also people need to realize that dragsters and F1s are designed to last a race or two, then they get a teardown and rebuild, or replaced all together. When you are looking for a few more HP with a disposable engine it's a different "application" of oil.

Obviously, the manufactures of vehicles for everyday "public use" are trying to use the thinnest oils possible to be "energy conserving" and still maintain a decent reliability and life expectancy of the engine under "normal public road use".

I thought these were interesting statements, and backup "go as thin as you can and still make a car last" theory.

Originally Posted By: yannis
If you google you will come across these statements.

"FORD which has previously designed cars to have 10 year or 150,000 miles life has reduced the mileage life expectation to "beyond 100,000 miles" on vehicles that are operated on SAE 5W-20 Motor Oil."

"HONDA only claims "useful life" as 7-years or 70,000 miles in EPA certifications for their CIVIC which uses SAE 5W-20 Motor Oil, while the previous model that utilized SAE 5W-30 Motor Oil was certified for 10 year or 100,000 mile durability."

 

[BuickGN]

Originally Posted By: FZ1
You're breakin' that car too much! You need to get some tires with less rear traction so you can spin them more easily and,therefore, take the strain off you engine and drive train. Then it won't break so often.


Street tires spin at 70mph. It's as much a matter of safety as it is performance. Breakage is ok, it's part of the game. When you consider the car hasn't broken in 3 years at this level using mostly stock parts, I can't really be upset.

 

[ekpolk]

Originally Posted By: BuickGN
. . .

When my oil looked like glitter, I assume if I can see it with my eyes it's way too large to be picked up with a UOA. Most wear metals were in the single digits and it was so bad I should've recycled the oil for it's metal content lol. What would your conclusion be when 3 UOAs showed everything was fine even though you're staring at the pretty sparkly oil, tear it down and see the rods and mains worn nearly to the backing, a big wear ridge on the cylinders, and the rings so worn that you can tell just from eyeballng them form a distance. I could actually feel that they were lighter which is something you usually can't tell in an engine that has gone half a million miles.


My conclusion would have been that you found yourself in an especially unlucky box in the analytical matrix. I think it's been pretty well established that the inexpensive UOAs that the vast majority of us use have a very definite set of limits. One day in the future, our descendants will be able to walk up to their car (if there are still such things) with a Tricorder, scan, and immediately learn that the oil control ring in #3 cylinder is failing.* If they're really lucky, their Tricorders might even sound as cool as the ones from Star Trek. But until then, we have to make do with what we have, and critically here, what we can afford. I use UOA with the complete understanding that it is a distinctly imperfect tool for measuring the things it purports to measure. I still find it a valuable monitoring tool, which can (not always will) alert me to look further into wear, leaks, changing product (oils, filters, etc) selections, etc. Back to your question, I'd probably have concluded, as you did, that I had a very, very sick engine. I would not, however, "throw out the baby with the bathwater" and completely dismiss the value of UOA, even though it certainly failed to help in this instance.

*EDIT: Oh yeah, I forgot to add that by then, ALL cars will be hybrids! And your great, great, great grandson will be tweaking his Buick GP (Grand Planetary, whose electric motors generate ~1k ft-lbs of tq), and constantly defending his seemingly insane insistence upon using the horribly thick 0w-5 museum oil. . . [where's that old raspberry smiley when you need it...]

 

[OVERKILL]

Originally Posted By: SuperBusa
Originally Posted By: BuickGN

I get condemned for posting my "race engine" results in the GN with my stock clearances and production parts using a thick oil to survive yet it's ok for you guys to mention Top Fuel and F1. And consider that valide. Here's a question, how much torque do F1 cars make?? You may find you answer in there.


Good question ... and yes, that's a factor. Also people need to realize that dragsters and F1s are designed to last a race or two, then they get a teardown and rebuild, or replaced all together. When you are looking for a few more HP with a disposable engine it's a different "application" of oil.

Obviously, the manufactures of vehicles for everyday "public use" are trying to use the thinnest oils possible to be "energy conserving" and still maintain a decent reliability and life expectancy of the engine under "normal public road use".

I thought these were interesting statements, and backup the theory of "go as thin as you can and still make a car last" theory.

Originally Posted By: yannis
If you google you will come across these statements.

""FORD which has previously designed cars to have 10 year or 150,000 miles life has reduced the mileage life expectation to "beyond 100,000 miles" on vehicles that are operated on SAE 5W-20 Motor Oil.

HONDA only claims "useful life" as 7-years or 70,000 miles in EPA certifications for their CIVIC which uses SAE 5W-20 Motor Oil, while the previous model that utilized SAE 5W-30 Motor Oil was certified for 10 year or 100,000 mile durability.""


The life of a top-fuel engine is also about 30 seconds, and that is if it makes a full-pass (obviously including start-up time, staging....etc).

I have a piston out of TJ Zizzo's top fueler sitting on my mantle. It is amazing to see the effects that making 8,000HP has on a forged piston. Every piston in that engine was caved-in in the centre, and that is NORMAL, since the car did not encounter engine failure that pass and was running ~300Mph.

Long-term durability is far from the primary concern

 

[BuickGN]

Originally Posted By: ekpolk
Originally Posted By: BuickGN
. . .

When my oil looked like glitter, I assume if I can see it with my eyes it's way too large to be picked up with a UOA. Most wear metals were in the single digits and it was so bad I should've recycled the oil for it's metal content lol. What would your conclusion be when 3 UOAs showed everything was fine even though you're staring at the pretty sparkly oil, tear it down and see the rods and mains worn nearly to the backing, a big wear ridge on the cylinders, and the rings so worn that you can tell just from eyeballng them form a distance. I could actually feel that they were lighter which is something you usually can't tell in an engine that has gone half a million miles.


My conclusion would have been that you found yourself in an especially unlucky box in the analytical matrix. I think it's been pretty well established that the inexpensive UOAs that the vast majority of us use have a very definite set of limits. One day in the future, our descendants will be able to walk up to their car (if there are still such things) with a Tricorder, scan, and immediately learn that the oil control ring in #3 cylinder is failing. If they're really lucky, their Tricorders might even sound as cool as the ones from Star Trek. But until then, we have to make do with what we have, and critically here, what we can afford. I use UOA with the complete understanding that it is a distinctly imperfect tool for measuring the things it purports to measure. I still find it a valuable monitoring tool, which can (not always will) alert me to look further into wear, leaks, changing product (oils, filters, etc) selections, etc. Back to your question, I'd probably have concluded, as you did, that I had a very, very sick engine. I would not, however, "throw out the baby with the bathwater" and completely dismiss the value of UOA, even though it certainly failed to help in this instance.


I think UOAs are valuable in determining the amount of life left in an oil. If I were pushing my intervals I would still pay for a UOA. However, I would ignore the wear metals.

With 3 back to back on one engine, how would you dismiss this? After the first one, I was paying for them trying to figure out why the heck they were coming back ok. It was obvious the engine was in trouble as my 0 oil pressure at idle indicated but I became interested in the UOA itself.

 

[CATERHAM]

Originally Posted By: BuickGN
Originally Posted By: CATERHAM
Originally Posted By: OVERK1LL
Originally Posted By: Ben99GT
I'm just trying to figure out how a 4400 mile engine with wear metals trending down over 1400 mile OCIs proves anything?

So if he switches back to 10W-60 and UOAs show wear metals fall again does that prove thicker is better?

I was wondering the same thing...... Not to mention using UOA's as the complete basis for this kind of argument is a huge
stretch to begin with.


If Ferrari new that under no circumstances would the sump engine oil temps ever exceed 180F I'd bet they would be specifying a 0W-20 oil and definitely not 10W-60. What a coincidence, that's what Dr. Haas is using!


That's pure speculation on your part unless you're a Ferrari insider.

Again, you sidestep the worthlessness of UOAs in determining wear.


It may sound radical for Dr. Haas to run a 0W-20 oil in his exotic hyper expensive cars, but the reality is that the lightest oil he's running in his application has a kinematic vis of 13 cSt ( 40 wt ? ) or heavier. Sounds pretty conservative to me.
What's much less conservative is ZoomZoom (see page 13 I think of this thread) running GC and now RL 5W-30 in his 365 hp Audi S4 at the track with 280F oil temps. By my calculation that's a vis' of only 5 cSt. And for those that give some credence to UOA as a tool, the're good.

 

[ekpolk]

Fairness Notice: I did edit the post to which you responded. Don't think it's a problem, though...

 

[OVERKILL]

Originally Posted By: CATERHAM

It may sound radical for Dr. Haas to run a 0W-20 oil in his exotic hyper expensive cars,


Not really. He has the money to replace them. He also doesn't track them, so they never see the kind of use that would stress the engine enough to need the protection of the heavier oil spec'd by Ferrari.

Quote:
but the reality is that the lightest oil he's running in his application has a kinematic vis of 13 cSt ( 40 wt ? ) or heavier. Sounds pretty conservative to me.
What's much less conservative is ZoomZoom (see page 13 I think of this thread) running GC and now RL 5W-30 in his 365 hp Audi S4 at the track with 280F oil temps. By my calculation that's a vis' of only 5 cSt.


Yes, that is pushing the envelope.

Quote:
And for those that give some credence to UOA as a tool, the're good.


Well, since Doug is an actual Tribologist with over 50 years of experience, unless somebody with equal credentials can prove otherwise, I am going to continue to use UOA's solely for the reasons Doug has dictated are reasonable.

 

[BuickGN]

Originally Posted By: ekpolk
Fairness Notice: I did edit the post to which you responded. Don't think it's a problem, though...


Which part and why?

 

[mechtech2]

zz - I know those graphs are for your car, but I'm sure approximations can be made for others from it.
Good generalizations and relations.
So thanks !

 

[ekpolk]

Originally Posted By: BuickGN
Originally Posted By: ekpolk
Fairness Notice: I did edit the post to which you responded. Don't think it's a problem, though...


Which part and why?


See the asterisk in the post. Not a biggie -- just having fun on the weekend. Hey, if this ceases to be fun, I'll have to retreat to a basket weaving site...

 

[FZ1]

Well,that's part of the fun. You just correct it. Lol. What kind of times does your little Buick run?
Originally Posted By: BuickGN
Originally Posted By: FZ1
You're breakin' that car too much! You need to get some tires with less rear traction so you can spin them more easily and,therefore, take the strain off you engine and drive train. Then it won't break so often.


Street tires spin at 70mph. It's as much a matter of safety as it is performance. Breakage is ok, it's part of the game. When you consider the car hasn't broken in 3 years at this level using mostly stock parts, I can't really be upset.

 

[BuickGN]

Originally Posted By: FZ1
Well,that's part of the fun. You just correct it. Lol. What kind of times does your little Buick run?
Originally Posted By: BuickGN
Originally Posted By: FZ1
You're breakin' that car too much! You need to get some tires with less rear traction so you can spin them more easily and,therefore, take the strain off you engine and drive train. Then it won't break so often.


Street tires spin at 70mph. It's as much a matter of safety as it is performance. Breakage is ok, it's part of the game. When you consider the car hasn't broken in 3 years at this level using mostly stock parts, I can't really be upset.


10.60@126 with a best mph of 129mph. I've taken 300lbs out of it and added another 75hp or so so it should run good next time out.

Spinning is fun sometimes but things happen very fast at higher speeds and while I've driven it sideways a lot and never spun out, my luck will run out one day. I used to enter the freeway around my favorite onramp at 45mph and punch it as the corner straightened and let it drift over 3 lanes into the fast lane.

 

[Gary Allan]

Originally Posted By: OVERK1LL
Originally Posted By: CATERHAM
Measuring boundary lubrication friction of valve train shims at very low rpm's may be interesting but falls far short of the entire picture of engine wear as a whole.

UOA measures engine wear in its totality.



And a snippet from Doug's article:

Originally Posted By: Doug Hillary

By Doug Hillary

UOAs are a great tool in the Management of any machinery that uses liquid lubricants. Unfortunately, their real value is often misunderstood by those who contribute to BITOG.

Firstly, it is important to realize that you get what you pay for. The most common forms of UOA are limited in their scope. It is a case of if you pay more you get more. So my comments here relate primarily to the “simple” UOAs – the cornerstone of those appearing on BITOG

Secondly, it is easy to assume that by carrying out a UOA you will be able to determine how quickly the engine is wearing out. As well, if you change lubricant Brands you will be able to compare the wear metal uptake results and then make a balanced best lubricant choice to make your engine last longer.

Sadly that logic is seriously flawed.

Single pass (random) UOAs will provide some information regarding wear metals but unless you have a history of your engine’s performance up to around 1 million miles the results are simply that – UOA results! As an example a limit of 150ppm of Iron is a reality – after say 100k it means the lubricant should be changed and all is well. But what is the situation if you have 150ppm of Iron at 5k? Where would you look what would or could you do? So UOAs are really a diagnostic tool – one of many!

The other parts of the UOA Report will be much more valuable to you – it will tell you about the CONDITION of the lubricant and its suitability for further use. This will enable you to get the maximum safe use from the lubricant saving a valuable resource in the process.


And another little part worth mentioning from the article:
Originally Posted By: Doug Hillary
During the last 50 or so years I have carried out hundreds of UOAs on all sorts of engine configurations – and on transmissions, gearboxes and differentials. These were done in consort with four Major Oil Companies (Shell, Exxon-Mobil, Castrol, Chevron-Caltex), my Employers, my Customers and on my own Fleet and other vehicles. Not once were they ever used to discriminate one lubricant from another on the grounds of wear metal uptake!



No arguments. However ..as Doug says right there ..these were lubricants spec'd for the service.

Ask him if he ever used 40-70 or SAE 30 in engines that were spec'd by the OEM for 15w-40 and 5w-40 and did any UOA's on them for comparisons of metal uptakes for the heck of it.


I'm not disputing anything Doug says ....that would be stupid, but I think you're reading more into what he's saying than is really there.

I'll stick my neck out and say that he never did any "what if" experimentation in any of his distractions. No "hold my VB and watch this".

What I glean from him is that ..hmm..under all conditions one can think of under the sun, for like spec'd lubes, all UOA metal uptakes fall into standard deviations that are accepted as normal up to condemnation limits.

I may have missed it, but while I saw some reference to "where did it come from?" in the 150ppm reference somewhere back, but what did (or would) Doug do when one tractor hit the condemnation limits for Fe at 1/2 of the normal interval for the rest of the fleet, just leave it in service at twice the downtime and twice the costs in maintenance? He knows it's not the lubricant that is the source of the issue.

We may evolve to including PQ index in UOA. Maybe Blackstone should invest in the machinery. That's one of the things he sorta mentions by saying "low cost". Suppose PQ and a few other things arrive to BITOG's UOA religious cult ..and the results offer the same conclusions as the witch doctors and seers more often than not?

It's like a fine surgeon giving a critical analysis of healers using stone knives and bear skins. They're going to be wrong more often.

 

[OVERKILL]

Gary:

I think PQ index would be quite useful. But may, as you mentioned, add to cost. I think that is why Doug makes it a point to make specific mention of LOW COST UOA's, many of which posted on this site, do not have TBN/TAN performed on them, which, what I understand from Doug's information, is one of the primary functions OF the test!

I know Doug runs 5w40 in one of his vehicles that isn't spec'd for it, but I cannot remember off-hand what it is. I think it may be his holder Porsche, which spec's a 50-weight.

It would be really nice if Doug chimed-in on this topic, I am going to PM him a link to it.

 

[Gary Allan]

Most who don't do TAN/TBN aren't challenging the limits of the product in those items.

Be assured that UOA is best used at looking at the lubricant under the service that it's subjected to. I would have to seriously see fault with UA being some metric of "normal" in terms of the metal numbers. That can be over tens of thousands of units over varied services and conditions. Is it "conclusive"? No. But it can't be discounted as an indicator for normal noise. When you see unusual noise, the sensible conclusion is that something is not right.


Doug surely accounted for lubricant evolutions in his alteration from OEM spec's on that Porsche. He used, iirc, just about the best oil that there is out there, Delvac 1, which is just about the most bullet proof oil in such wide distribution. I'm pretty sure that he didn't opt for the ultimate primo M1 offering, 0w-40. The one that inspired visions of legions of high end car drivers engaging in genuflections at hearing it mentioned.