Cold Start Thickness - Dr. Haas

[Art_Vandelay]

According to Dr. Ali E. Haas (AEHaas) in an article I read at: http://www.ferrarichat.com/forum/faq.php?faq=haas_articles

These are the various cold start thicknesses at 75F. No wonder the most amount of engine wear occurs at start up. Anyone know what the numbers are for Mobil 1 0W-20?



Quote:
Oil type... Thickness at 75 F...Thickness at 212 F

Straight 30...... 250......................10
10W-30............100......................10
0W-30..............40 ......................10

Straight 10........30....................... 6

- Dr. Ali E. Haas (AEHaas)

 

[ADFD1]

Which is why even at 75*F a 0W-xx or 5W-xx oil will give better start-up protection than a 10W-xx, 15W-xx, or 20W-xx..

AD

 

[jigen]

Originally Posted By: ADFD1
Which is why even at 75*F a 0W-xx or 5W-xx oil will give better start-up protection than a 10W-xx, 15W-xx, or 20W-xx..

AD


This has always had me wondering... How accurate is this? Based on this chart you would think an 0w would be ideal in almost all conditions.

 

[Gary Allan]

Quote:
These are the various cold start thicknesses at 75F. No wonder the most amount of engine wear occurs at start up.


That's a play on words. Most wear occurs between starting the engine and warming it up fully.

I still need to see the quoted text were warmer oil in a cold engine produces less wear than colder (not refrigerated) oil in a warm engine over a broad range of like and diverging regulated oil temps.

In the fine doctor's cited references, the acclaimed Schneider measured cylinder:ring wear during the warm up event. It forms a curve of decreasing wear as you approach full warm up.

One cannot attribute this curve to viscosity ..at least too much to it ..otherwise one could surely just reduce/shorten the curve with lighter oil. One can attribute it to warming, but I've not seen the data that assures that it's additive activation or the fitment of parts with various expansion properties that are integrated into the "warm up" process. When "steady state" status is reached, all of these parts are also at equilibrium as evidenced in oil temperature.

This is one item that I have not seen nailed down in any absolute manner.

 

[ADFD1]

Based on the chart for PC applications, not racing, or HP apps I'd give the 0W the thumbs up in most applications. The downside is the 0W oils only come in synthetics, but that could change. JMO

AD

 

[ADFD1]

Originally Posted By: Gary Allan
Quote:
These are the various cold start thicknesses at 75F. No wonder the most amount of engine wear occurs at start up.


That's a play on words. Most wear occurs between starting the engine and warming it up fully.

I still need to see the quoted text were warmer oil in a cold engine produces less wear than colder (not refrigerated) oil in a warm engine over a broad range of like and diverging regulated oil temps.

In the fine doctor's cited references, the acclaimed Schneider measured cylinder:ring wear during the warm up event. It forms a curve of decreasing wear as you approach full warm up.

One cannot attribute this curve to viscosity ..at least too much to it ..otherwise one could surely just reduce/shorten the curve with lighter oil. One can attribute it to warming, but I've not seen the data that assures that it's additive activation or the fitment of parts with various expansion properties that are integrated into the "warm up" process. When "steady state" status is reached, all of these parts are also at equilibrium as evidenced in oil temperature.

This is one item that I have not seen nailed down in any absolute manner.


Gary, wouldn't the 0W reach its operating viscosity faster than a 10W? I read that report a few times and the Dr used a scale of 1-10 IIRC. Lets say 10 is the level the oil works best at 100C. Then lets say a 10W starts out at a 3, and a 0W starts out at a 5, the 0 will get to 10 sooner? Its been a while, and I've been up since 0300, go easy on me. But I think that was the concept he was trying to bring across?

AD

 

[saaber1]

Originally Posted By: Gary Allan

This is one item that I have not seen nailed down in any absolute manner.


You could send a pm to wjdell (sp?) on this forum as I think the vw diesel guys track fe ppm pretty close on tdiclub.com. I am almost certain they would have before and after UOA examples of ppm fe for before and after daily use of an engine oil heater. It may shed some light on the subject but is not definitive for sure.

 

[Bryanccfshr]

The oper4ating viscosity is reached only once the operating temperature is reached. No faster with thinner oils just that the oil is less thick during this process.

Cold oil (such as in the Seq IIIA test does not work as well as oil that is up to temperature. Viscosity and antiwear additives working better at temperature may contribute.
TO be completely unbiased Once could match viscosities of different oils at differnt viscosity curves(a 60wt oil at 100°c vs a 20 wt at 40°c , hypothetical not scientific example,)in a sequence test with the same additive package. If the temperature is the issue the 20wt will perform worse despite the fact that in this hypothetical example they are both at the same viscosity in the test. IF there is no difference in wear the assumption would be that viscosity and poor oil circulation/distrubution contribute to warmup wear.

 

[Gary Allan]

Quote:
Gary, wouldn't the 0W reach its operating viscosity faster than a 10W?


I can't see how. It will still take so many btu's passing through it that aren't being absorbed by the engine. It's still a 30 grade.

That is, at whatever visc it may end up at, it's probably going to take around the same time to reach 100C due to the combustion process introducing thermal energy. The engine components themselves are also going to be soaking up this thermal energy.

Engines that are heat exchanged have normalized oil temps quicker than would normally occur.
Originally Posted By: saaber1
Originally Posted By: Gary Allan

This is one item that I have not seen nailed down in any absolute manner.


You could send a pm to wjdell (sp?) on this forum as I think the vw diesel guys track fe ppm pretty close on tdiclub.com. I am almost certain they would have before and after UOA examples of ppm fe for before and after daily use of an engine oil heater. It may shed some light on the subject but is not definitive for sure.


Yeah, but how are you going to differentiate between shortening the warm up event for the engine vs. warm oil? I mean do we know if there was added wear due to cold oil flow ..warm block ..warm oil cold block. How about warm oil warm block. Where was the introduced heat reducing the wear? In terms of additive activation, fast flow, faster thermal expansion of parts?

It could be a tough test to run. I guess you could run two blueprinted engines side by side. Have them reach "steady state" and then switch one to substantially colder oil (let's say 40C and of the same effective viscosity - maybe) run them both for 100 hours and measure the wear.

Those that suggest that hot oil is the reason, can't resolve the fact that the upper pistons should reach additive activation levels quite early with whatever oil is used to contact the cylinder walls. The cylinders themselves should be warm much earlier in the warmup event than the wear curve indicates.

It confounds reasoning.


Edit and in short: If steady state wear could be achieved by just heating the oil, then everyone with an oil warmer should be able to experience virtually zero wear. I don't think this has been proven to be true.

 

[Art_Vandelay]

So any time prior to reaching operating temperature, (212F in this case), all oils cause more wear?
This results from not yet being at the viscosity of 10?

So if this is true then during the warm up phase isn't a viscosity of 40 less damaging than a viscosity of 100. Also even if they both take the same amount of time to reach 10, isn't the 0W-30 hitting 20 at the same point the 10W-30 is at 50? How is that not better for the engine?

 

[Bryanccfshr]

That is one way of interpreting the data(one wich I side with) but to be objective and fair you also have to consider the thermal expansion and engine fitment issues during warmup at lower temperatures as well as additives( Gary makes a good point and I am not certain about additives needing flash exposure to heat or a sustained heat to remail active).
There is simply alot of variables occurring that could contribute to the FACT that engine wear is accelerated during warmup. The best way to decrease the effect is to warmup under light to moderate load. No load warmup extends the time of warmup and would logically be undesireable for engine longevity.

 

[Gary Allan]

No. Before oils reach their normalized temperatures ..more wear is occurring. I've not seen conclusive evidence that it's not a normal process variable of the engine components reaching thermal saturation ..at least in terms of cylinder:ring wear.

Dr. Haas suggests that it's due to viscosity. I offer that it can be ill fitment of parts (at least in terms of cylinder:ring wear). When the wear event reaches zero ..it's also when the oil is at operating/normalized temp. It's also when the engine is done absorbing free btu's and is ejecting them out through the oil. Heat is an equal opportunity escaping agent.

That is, the oil is an indicator of thermal saturation. So, warm oil may have greater additive potential, but it always coincides with the internal parts reaching their normal expansion limits. Pistons are fully expanded ..etc..etc.


Edit: Using heated oils for testing (in a lab) would probably still leave speculation as to the relationship. If one suggests that heated oil ..and the additive activation thresholds, are the principle wear reduction agents, then one should experience zero wear with heated oils. I don't think that would be the result of such testing. Reduced wear, maybe ..and maybe even greater reductions than cold oil in a heated engine, but I'm pretty sure it will be a combination of the two actions that are responsible for the "90% of wear that occurs at startup".

 

[SpitfireS]

What about oil flow?
At a certain engine rpm a thinner oil will flow quicker and at a lower pressure, right?
This lower pressure will also not open the oil pump bypass valve or open it less, so more oil flows through the engine - and picks up heat - instead of being dumped in the sump.

 

[river_rat]

My owner's manual says 0W-20 or 5W-20--but 0W-20 is "preferred."
I reckon a 0W-20 is better than a 5W-20 or, for that matter, a 20W-20 for start-up/warm-up wear any way you cut it. And that's as hard as I'm willing to think about it.

 

[Gary Allan]

Originally Posted By: SpitfireS
What about oil flow?
At a certain engine rpm a thinner oil will flow quicker and at a lower pressure, right?


Well, it will flow the same at lower pressure. It will flow at what ever rate it will flow. It may flow easier (require less power to flow at that rate).

Quote:
This lower pressure will also not open the oil pump bypass valve or open it less, so more oil flows through the engine - and picks up heat - instead of being dumped in the sump.


In most cases... if the oil isn't flowing "full flow" through the engine, it's because it's either too cold or too high a visc (usually the same thing - but not always) ..so there's not a whole lot of benefit to carrying away heat except to move the oil into a more favorable viscosity where it does "fit" full flow through the engine.

 

[INDYMAC]

OK, so we have this hypothesis that various 30wt multi-viscosity oils have different viscosities at ambient start temperatures. We even have some 0W-30 oils that are thicker than 5W/10W-30 oils at ambient temps (especially after they shear down if they are energy conserving labeled).

And then we have the hypothesis that most wear occurs at start-up. Yet we don't see any significant wear change trends on UOA's from members that have tried numerous viscosity oils in the same equipment.

What we do see more often than not is fuel dilution, fuel additives, silicon, and anti-freeze causing more wear than engine starts could even begin to compete with. The viscosity of the 30wt oil is insignificant as a variable IMO. 0W/5W/10W-30 oils will all protect about the same, until you get below freezing temperatures.

 

[jigen]

Now I am confused lol. In the summers here I usually run 10w30 and in the winter 0w or 5w30. Should I just stick with one grade?

 

[Gary Allan]

jigen ..welcome to the clear mud

It probably doesn't matter all that much. One would sensibly use the lightest oil that one can use that works in the service you're going to subject it to. For most that means a 5w-30 under all conditions. It may not in yours.

Are we talking about that LS1 Camaro?

 

[jigen]

Originally Posted By: Gary Allan

Are we talking about that LS1 Camaro?


lol, we sure are.

 

[scoobie]

It seems to me it is worth having the block heater plugged in for 1-2 hours to pre heat it in the morning prior to leaving. I bought a really nice digital timer, and I installed an oil pan heater and a block heater for good measure. I also discovered that you should GET A GOOD QUALITY THERMOSTAT, such as what NAPA supplies. A new NAPA thermostat, plus preheating my engine, results in engine reaching full operating temperature within about JUST ABOUT SIXTY SECONDS! Also, for daily driving, 5w30 is better than 10w30, but for example, a synthetic 10w30 will have the same cold properties as a conventional 5w30, so that comes into play as well.