Does 0w-40 lack film strength?

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I found this post from one of the oil gurus at Clubb5.com which is the VW Passat site. The Passat's generally have the VW/Audi turbo 1.8 engines so this person maybe speaking to the 1.8 engine. Regardless, I thought I'd get some of your thoughts on this:
quote:
-------------------------------------------------------------------------------- I am going to get very technical here. Reynolds' equation is used to relate the thickness of the oil film required to support a load to the minimum viscosity required to maintain the film. From Reynolds, one can propose a film thickness and calculate the minimum viscosity. This must take into account the average surface roughness of the materials as the film height must include the maximum dimensional tolerances. This will give the minimum viscosity required to maintain a hydrodynamic lubricant film. To reduce the minimum film thickness required to support a load, the other two regimes of lubrication must be called into play. These are boundary and Extreme Pressure. Both are dependent on an active oxide layer on the metal surface. If the oxide is abraded or worn off, these lubricants ("additives") will not be very effective. The role of an anti-wear agent (the beloved ZDDP) is to replace the oxide film with a more tenacious and reactive layer and render the boundary and EP additives functional in a high wear situation. What the Dr. is describing is what happens when the viscosity of the oil is too thin to support the film thickness required to maintain a hydrodynamic film and the additives are insufficient to prevent catastrophic wear. No motor oil has sufficient additisation to prevent catastrophic wear under sub-par film conditions. In the high-speed environment of an engine, there is little reason to run at the ragged edge of viscosity. You are playing with your car here. TBH, newer synthetic stocks are available which have massive VIs and can meet the 0W40 specs with very little VI improver. If you are complaining about the price of Mobil1, don't even ask how much these oils cost. Since 0W oils inherently lack film strength at certain temperatures due to reduced viscosty, I strongly recommend against them for normal use. The drive to 0W oils comes from fuel economy standards. As the engines becomes trobologically optimised, the principal contributor to reducible friction is the internal friction (viscosity) of the oil. Since this can be reduced, that is what is going on with the demands by the engine builder for 0W. Supposedly the reduction in internal friction makes a measureable contribution to fuel economy. With the demands of the CAFE standards, any little bit helps.
 
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Mobil 1 0W40 is not an Energy Conserving oil. I don't think it was designed with fuel economy in mind. It had to many other standards to meet, including a high HTHS and good viscosity retention under extended drains and high speeds. This is the same oil that handles a Timken test Very well. There are several people on this forum (including me) who are running evaluations on it right now. I intend to run mine until it is recommended to change it, to see how far it can go. It will be interesting to see the results.
 
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I don't know, but it's not. It is a 0w... cP in CCS test is below limit for a 0w. So if someone said that, that makes no sense... Besides no such thing as 12w. Would be a 10w or 15w, depending on CCS results.
 

MolaKule

Staff member
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You only gain approx. 1.5 um film thickness with each step increase in SAE grade. I suspect this guy is far behind in Boundary Layer technoology since we now have the new esters and additives such as moly (MoDTC) and antimony (SbDTC). I would suspect that some economy oils are still made with low viscosity starting bases and add VII's to get to 40 grade, but most oils are much better now. And the synths start out closer to 40 weight than do the dinos.
 

MolaKule

Staff member
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"No motor oil has sufficient additisation to prevent catastrophic wear under sub-par film conditions." If you lost oil pressure, shut the engine down as soon as possible and had an oil with good boundary friction modifiers, then the results should not be catastrophic. If you were an idiot and kept driving until the bearings melted, well then....
 
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Here is a test I performed with Esso's original 0W40 XD-3: 40C......80 100C.....15.6 VI.......210 SA.......1.25 TBN......10.0 engine: BB Chev 10.5 462 CID Valve train: HYDFT, cam lift .345, rocker 1.70, valve lift .580, spring seat 150#@1.95, at .580 lift 330LBS, valves 2.30/1.88 #2 eng : SBC 355 CID 2.05/1.6 11.0 CR CAM lift .340 MFT, 1.6 RR net at valve lashed: .520, spring 145#@ 1.85" spring @.520 lift 320# The cams and lifters "lived" in both of these engines proving to me that the 0W40 provided the required protection.
 
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quote:
Originally posted by VaderSS: Mobil 1 0W40 is not an Energy Conserving oil. I don't think it was designed with fuel economy in mind. It had to many other standards to meet, including a high HTHS and good viscosity retention under extended drains and high speeds.
It IS labeled as "Energy Conserving" and also carries API SL/CF and ACEA A3 ratings. That is what makes it so interesting to me. It seems to be able to "do it all".
 
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quote:
The drive to 0W oils comes from fuel economy standards. As the engines becomes trobologically optimised, the principal contributor to reducible friction is the internal friction (viscosity) of the oil. Since this can be reduced, that is what is going on with the demands by the engine builder for 0W. Supposedly the reduction in internal friction makes a measureable contribution to fuel economy. With the demands of the CAFE standards, any little bit helps.
I may be wrong here, but I thought that the MPG under CAFE standards is measured with the engine already warmed up. This means the first figure (0w) does not matter much, because by that time the oil behaves like the second figure (40, in case of an oil like 0w-40). [Confused] That's why there is a push nowadays to use Xw-20 type oils. Another words, reducing the second number has an effect on CAFE, not the first one. Using 0w-XX oils just helps engine lubrication in very cold starting temps. And when the engine is cold, film strength doesn't matter all that much since the assumption is that you're not pushing it so hard anyway because you're letting it warm up gently.
 
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Pete, I think you are correct, and my camshaft test confirmed that the second number is what counts. If any engine is going to eat a camshaft it is the big block chev with its small cam base circle, .843" dia lifters, 1.72 rockers, 1.55" od valve springs, and lifter bore indexing all over the map. Camshaft break-in procedure is very important with these engines. I have found that many people go over the top during the initial camshaft run-in by over-heating the engine oil, then losing the cam.
 
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This is as far back as I could find 0W40 and film strength being discussed on BITOG. The obvious difference then vs now, is the KV100 and anti-wear concentration levels of the early 0W40s. It must have been later on when everyone jumped on the 0W40 bandwagon with cheap imitations, trouble started.
 
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Originally Posted By: used_0il
It must have been later on when everyone jumped on the 0W40 bandwagon with cheap imitations, trouble started.
Wow... way to raise a 12-year-old thread from the dead. But I'm curious, what trouble are you referring to? Did someone lose an engine by running 0w-40 in it??? Cheap imitations???
 
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Everything Molakule posted back in 2002 is still very relevant today - in fact maybe even more relevant with developments in the new fuel economy engine oils. (0W16 here we come!)
 
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Hi, I have been a long time user of M1 0W-40 - this I believe was the first widely available product with this viscosity. It always met ACEA A3/B3, Mercedes and Porsche specifications and of course was their FF I've used it in a wide range of engine families (motorbike, petrol, diesel) - German, Japanese, Chinese, and in some cases over very large operational distances. In temperatures ranging from -10C to >50C, at high speed long distances, sometimes heavily loaded, and, I never personally had a problem with this product in any of its formulations! Nor may I say, have I ever heard of any lubrication issues with it - from the Nurburgring to the road - and of course in its intended application!! It took several years after M1 was introduced for other Oil Companies to introduce their own 0W-40 products I still use M1 0W-40 today - over nearly a 15 years period!! Why was this Thread re-activated? What is the motivation
 
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Originally Posted By: Doug Hillary
Hi, Why was this Thread re-activated? What is the motivation
Great question, I was thinking the same thing.
 
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Testimonials and "me too" posts. How did one member describe it today? Oh yeah. "The BITOG Cold-Flow Fanboy Club". Lets assume that we had only one grade to choose from, well 0W40 would be the one. I posted two variations of the grade from Mobil with contrasting additive packages and application. Now it's your turn. Please explain why the entire engine oil fraternity does not share the same glee for 0W40 instead of 5W40 for example. In fact, I could find more variations and applications including manufacture certifications for 5W40 than 0W40. Show me a certified 0W40 CJ-4 for starters.
 
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