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Wow, never knew that.
Start up wear, Normal wear, and the relation to various oil properties. SAE 2006-01-3414
- Thread starter AEHaas
- Start date
Castrol's Magnatec was designed around this condition. The additives unique to their chemistry were designed to work immediately before heat would allow ZDP to work from what I understand.
"In one of you previous posts you mentioned how you like to rev your expensive engines when cold, you being unwilling to let them warm up first."
As I leave my neighborhood I turn immediately onto a very busy highway with a lot of traffic moving at 55 - 70 MPH. I can wait for a period of time until you can pull out with very slow acceleration. It is what you must do if driving a Prius for example. Or you can pull up to the highway and just go, by gunning it. That means stepping on the gas and getting up to 60 or 70 MPH in like 3 or 4 seconds up to 9,000 RPM. 'Quite fun to do actually.
Ali
As I leave my neighborhood I turn immediately onto a very busy highway with a lot of traffic moving at 55 - 70 MPH. I can wait for a period of time until you can pull out with very slow acceleration. It is what you must do if driving a Prius for example. Or you can pull up to the highway and just go, by gunning it. That means stepping on the gas and getting up to 60 or 70 MPH in like 3 or 4 seconds up to 9,000 RPM. 'Quite fun to do actually.
Ali
I've been on here just about as long as you have and I've never seen anyone state that, much less "many" poeple.
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“One would not expect there to be a significant difference in wear when cold due to grade. All grades are very thick even at room temperature and have a high MOFT to protect the components.”
Post #2 by kschachn, From Upper Midwest, Joined Dec 26, 2005
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There you go...In this very thread. That was you right? The MOFT is Very High when the engine is cold, much higher than when the engine oil is 220 or 240F. Yet there is much higher wear when the engine/oil is cold. There should be no wear as the MOFT is so high, but the wear is high anyway.
There should be no wear, even without any additives according to the “high MOFT” crowd. I believe they imply that if you have a proper MOFT there should be little to no wear. People state that cold engine wear is a result of parts not fitting correctly until the engine is hot. But MOFT is MOFT so when it is plenty high how can there be wear.
There is more to it than this simple explanation that will supposedly prevent engine wear. It is much more complicated. You will not prevent start up wear by putting a 60 grade oil in your engine.
ali
There is always wear. No film thickness vs. wear graph ever shows zero wear.
And again, the wear is higher because of the lower temperature and the ineffectiveness of the additives. You have wear due to the film thickness and ancillary wear due to the effect of additives. What is the absolute difference? The statements you are posting give no absolutes only relative rates - which you yourself acknowledge.
And yet again there will always be wear but without absolute values the discussion is a bit worthless. As you note, 10X of some miniscule value is still... minuscule.
If you want to post something that deviates from years of science and solid physics you're going to have to do better than this. The post you made is full of enormous logical and factual holes and you don't seem to see any of them. I'm not necessarily claiming the study itself is full of holes, it's your portrayal, analysis and conclusions that are the problem. It would help if you linked the actual paper or study for all of us to read.
The link to the original paper is on the original post #1. The conclusions written on my original post are from the paper, not from me. It would be of benefit for all to read, I believe. Though we may all still interpret their conclusions differently.
Ali
Cavitation is a good topic and also why I think thinner oils are better under high stress. I believe that better, easier flow minimizes cavitation.
Ali
Cavitation is a good topic and also why I think thinner oils are better under high stress. I believe that better, easier flow minimizes cavitation.
OK, I see what you are saying about flow, but with an oil pump and oil its more about the pumpablility and pressure.
Check your fly, Ali. Your cognitive dissonance is hanging out.
We all, and I mean all of us, can and are triggered into cognitive dissonance. There is no way for us to know when we are experiencing it. Others can recognize it if they know what to look for. We cannot recognize it or learn to recognize it in ourselves. It's just how we're wired.
They cooled the entire engine back to room temperature and the wear rates returned to the initial cold start rates. This demonstrated that the wear rate correlated to temperature. This study showed that cold wear rates were not related to viscosity.
Contrast that to your statement where you focus on the oil viscosity and ignore the fact that the entire engine was cooled back to steady state room temperature with all the associated causes of wear. The study found no correlation with wear and viscosity yet that's what you focus on because it's what you have to believe. Classic cognitive dissonance.
Ed
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This bit of information comes not from data from the Ford paper you are taking about. It was from a study referenced by the authors. That study used non fully formulated oils. A ZDDP only tribofilm was formed, detergents were added to the oil which removed the film and rebuilt a new tribofilm. It has no relevance to changing fully formulated motor oils.
The scope of the study was to see how long a motor oil could form an effective anti-wear film. Uncontrolled variables preclude using the data from this study from drawing conclusions about wear from fresh oil. One of the major variables that was not controlled in this experiment was the fact that the fresh oil was always run on new parts. The used oil was always run on broken in parts. There is no way to determine how much break-in wear contributed to the wear seen using new oil.
Ed
As I understand it MOFT comes into play at the bearings but not at the valvetrain. So the question is what is the source of the minuscule but measurable increase in wear on a "cold" engine?
The combination of cold temperature and higher viscosity from that cold temperature means anti-wear additive response / reactivity is significantly reduced. The valvetrain relies on anti-wear additives, not MOFT, to limit wear.
Well I made a 9 year real world study (still going on).
I haven't changed the oil and filter on my 2002 Explorer (daily driver) for over 100000 miles now.
And yes, I have to top it off from time to time, but not much.
Still running just fine - no engine issues whatsoever.
To be fair - I have to say it doesn't see much more than 2800 rpm most of the time.
Do I get wear? Of course.
More than with regular oil changes? I'm not sure.
I bought the car with about 100000 miles on it - now it has 236000ish - still the original V6.
No high oil consumption, normal mileage, no unusual noises or noticeable power loss so far.
And yes - that goes against everything I thought I knew about oil and engines.
Now reading Ali's first post with that study - especially that:
"Lubricants that were aged with 16,000 normally driven miles were compared to fresh lubricants and had similar rates of wear."
made me think.
Frank
You’ve got some stones!! How often do you have to add oil, what type and how much?? Thanks
Between half a quart to a quart every 6 months - and usually it's the cheapest no-name 10W-40 dino-oil I can find in my local supermarket.
Frank
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Your two quoted comments are related, the bolded part in the 2nd one is one reason RPM is limited until the oil gets above a target temperature. Plus they want the engine clearances to setttle down from warm-up before allowing redline use.
I don't recall anyone making that claim (the bold part). It's been mentioned many times that MOFT (the "film thickness"), a function of viscosity and relative speed of the moving parts, is the main thing that keeps moving parts sepatate, and that the AF/AW package (the "film strength") is the second line of wear mitigation that takes over when the MOFT fails and parts start rubbing on each other. Machinery Lubrication website article explaining this has been linked many times in these kind of threads. There is always some rubbing going on between parts in boundry and mixed lubrication, so the oil film strength (the AF/AW additives) is obviously always important too.
One reason there can be more wear with thinner oil is because more wear protection is being put on the film strength and not the film thickness. In that case, a more robust AF/AW package is benificial, but it can't mitigate wear as effectively as the film thickness (MOFT).
Theory is that the new oil strips off most of the AF/AW tribofilm (the "film strength") of the previous oil run off of the engine surfaces. If the tribofilm is weakened, then incteased wear occurs until the tribofilm is built back up from the new oil.
Pretty rare that journal bearings exhibit enough cavitation to damage the bearings - ie, mechanically pitting of the bearing surfaces. I've never seen that happen. Has anyone here seen cavitated journal bearings on any engines they have tore down?
The materials and surface hardening factor is also part of the wear equation in a valve train. Use bad materials and/or don't harden them correctly and wear will be a problem.
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