Automotive Longevity. How Long Will it Last

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-- If we are talking about engine wear in general and not the accelerated wear caused by dirty intake air, I would suspect that rod bearings are as susceptible to wear as the piston rings are. The main difference is that worn piston rings will be much more obvious due to reduced performance, increased blow-by, increased oil consumption, increased carbon buildup, etc. Worn rod bearings don't show themselves much until the wear is excessive, and tell-tale rod knock starts. They were very likely to be wearing badly before the knock started.
-- Among all the various filters found on a vehicle, there is no question that the engine air filter has the largest affect on engine longevity.
-- I have read many times that engine oils do their job best when at normal operating temperature. This goes against your practice of redlining the engine while using thinner oil that has not yet reached full temperature.
-- Keeping regular service intervals with quality oil and quality oil filters will always keep a clean engine, unless the design is faulty. Many people running 10k-20k miles on an oil service interval will have clean engines because the appropriate interval depends so much on the way the vehicle is driven, the capacity of the sump, the design of the fuel system, and many other factors. So the engine cleanliness factor can easily be removed from your engine wear experiment and I don't see any discussion warranted here.
-- I won't comment on the topics of hot & dusty operating environments, cold start temperatures, oil sump temperatures, or running thinner vs thicker oils because I don't have the time or interest to fully elaborate my thoughts there. To post these topics regularly, you must be retired or at least independently wealthy. Not everyone is so fortunate, not yet anyway :)
-- Finally, your experiment includes a sample of one (1) and your conclusions are beneficial to you alone, or anyone who happens to have the exact same model, mileage, condition, environment, maintenance history, etc. In other words, it only benefits you although I understand you want to share your findings with anyone who may be interested.
 
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My buddy ran a 283 Chevy for 80,000 miles with no air filter at all, I believe this started at about the 50,000 mile point. That was a time when 100,000 miles was considered useful life. The car was scrapped due to rust. However it was in a damp not dusty climate, NE Ohio.
 

BeerCan

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Sump temperature. This is also a recurring theme. While bursts of throttle will not heat up the sump a constant high load will do so. Towing big loads up mountains in mid summer will hurt. It will not cause catastrophic wear but rather accelerated wear. That is to say more wear than usual. In general things that run hotter wear more. It begs the question. Under normal loads thicker oils run hotter. Would you be better off using a thinner oil and run cooler as I always do? Wear analysis in my engines support this theory.
Curious about the engine wear analysis. Can you explain how it's done? How much does it cost? Just wondering.
 

AEHaas

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David (dnewton3),

First, thank you for all your work. We need more dedicated people willing to collect and analyse data. I have seen the other projects and already read yours as well.

The problem with all studies is to standardize and control things however. And one should not base the final conclusion on a single study or two. The more data we see and analyse and with better controls, the better. Even highly controlled lab studies, though valuable cannot by itself be the final word. And the field keeps changing so keeping up is hard as well. Perhaps the best study to date is the last few decades of 20 grade oil use. I remember when it started and almost nobody at this web site would have thought it would work. To make it even more interesting we are going to even thinner oils with even thinner HTHS and yet the world is still turning.

For example everybody quotes the need for higher HTHS viscosities in a couple of studies. Yet the cars of yesteryear were using straight 30, 40 and 20W50 grade oils and the engines did not last 100,000mi. Many of todays high revving race cars are using very thin oils and are required to use the motors over and over again without allowing a rebuild. And often the parts are smaller so as to save space and be lighter. So there must be more to that picture.

How big must a study be? There was a study in the 1960s to see if decreasing blood pressure would decrease the number and severity of strokes (not like bore and stroke for you car guys). The study was to be over several years. But it was almost immediately stopped as the results were so obvious regarding the effects of controlling BP. Another study may be to see if you can kill a person by dropping them off a 10 story building. It may be that the sample of One is good enough to draw a conclusion.

Review my study of two almost matching Enzo Ferrari cars. Same location, similar drivers, same weather et cetera.
The study is as controlled as I could make it. For example, only I take the samples. When I take the samples I clean the oil plug and then take only a mid stream sample of oil. Using the same lab, a better one, is best. When I change the oil I take apart the oil lines to get as much of the previous oil out of the engine. As all my cars have been newish there has been no contamination with “old” deposits dissolving or contaminating results. The results are similar to other sports cars I have tested so I believe the results are significant. This despite a sample of only one or two. But again, taken together the results are more significant.

If the thinner oils I have used were destroying my motors as so many have assured me, then it seems that oil analysis, magnetic oil plugs, paper oil drop reviews would show some dire results. Yet I have not seen anything to suggest I have issues.

My experiments are guided in part by what others say whom I respect. I do the best experiments I can using what I have to work with. I take the time to show my data as I am one of but a few who advocate thinner oils. I take a lot of abuse for it. I do not take into account anything from those who say things as I drive like grandpa or that I’m just a doctor and therefor know nothing about oil. I feel sorry for those commentors.

Regarding filtration. I am thinking that oil filtration and cleanliness is best addressed by changing the oil more often as I believe the number one thing causing wear is dirt in the oil. Air filtration is still up in the air but I am changing the filter more often anyway.

ali

PS. There is no down side for our environment to changing oil more often. After all, it is all recycled.
 
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To make it even more interesting we are going to even thinner oils with even thinner HTHS and yet the world is still turning.
Engines that are specified to run something thinner than xW-20 are typically incorporating special mechanical and materials design features to run those oils, and also it's been said those thinner oils are relying more and more on the AW/AF additive pack (film strength) than the viscosity (film thickness/MOFT) to combat engine wear. Some studies have shown that running oils with HTHS at 2.6 cP and below can accelerate engine wear in some components (rings being one of them). Those studies were way more controlled than anyone on this chat board could ever do in their garage.

For example everybody quotes the need for higher HTHS viscosities in a couple of studies. Yet the cars of yesteryear were using straight 30, 40 and 20W50 grade oils and the engines did not last 100,000mi. Many of todays high revving race cars are using very thin oils and are required to use the motors over and over again without allowing a rebuild. And often the parts are smaller so as to save space and be lighter. So there must be more to that picture.
As you've said "oils are a lot better than they use to be" - regardless of the viscosity. Engine design and much cleaner A/F ratio control is also a lot better on engines these days. Those cars that "did not last 100,000 miles" didn't last that amount of mileage because of the oil viscosity used. You seem to be making an underlying statement/theory that the use of thicker oil was the cause of them not lasting as long as today's cars. But I'm sure there were plenty of cars back in those days that did last well over 100K miles. Certainly cars going to the junk yard with 100K or less miles on them back then was not actually the norm. It just gets portrayed that way for some reason.

Regarding filtration. I am thinking that oil filtration and cleanliness is best addressed by changing the oil more often as I believe the number one thing causing wear is dirt in the oil. Air filtration is still up in the air but I am changing the filter more often anyway.
Some oil filters today are way more efficient (99+% @ 20u) than they were in the past. The longer the oil is ran and the smaller the sump, the more a high efficiency oil filter will help to keep the oil cleaner. Running a high efficiency oil filter isn't going to hurt anything except cost you a few more bucks - one less cheeseburger or latte.
 
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AEHaas

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"You seem to be making an underlying statement/theory that the use of thicker oil was the cause of them not lasting as long as today's cars."

Sorry for the confusion. I was saying that the oil had more than enough HTHS viscosity such that the wear was from something other than the lack of sufficient viscosity. I was not trying to imply the oil was too thick causing more wear.

ali
 
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I am curious, Dr Haas, how you will judge the "longevity" of the engine from your testing? I'm a statistical process quality control engineer by trade. I question your ability to make any sound conclusions from your experiments with such short durations, uncontrolled variables, and minimal data points. Your conclusions will be anecdotal at best. That does not take away from the fun and joy of doing so, but I caution you and others not to attach too much (if any) creedence to the results.

As I had before, I question your rationale of changing air filters 2x more than required. I don't know that anyone has advocated for blindly running really long FCIs for air filters. But I trust the data from Parker, Fram and others which our member Jim Allen gleaned in his research and expounded upon in his published article (see below) a few years ago; that air filters pass the vast majority of the total particulate they will ever pass in the first 10% of their lifecycle. Hence, changing filters 2x the OEM recommendation (which is probably already more often than necessary) will only increase the net amount of particulate passed into the engine. I quote the article: "This is why early or overly frequent filter changes are not advised because, according to Wake, 90 percent of the lifetime amount of dirt that passes through a filter does so in the first 10 percent of use."

There are some studies (SAE and other; below) which show that longer OCIs are beneficial in terms of wear rates. SAE study by Ford/Conoco (2007-01-4133) shows that longer OCIs can reduce the rate of wear. Before anyone lamblasts this as heresy, I suggest they purchase and read the SAE article. Further, macro data study from thousands and thousands of UOAs echos this very same thing; longer OCIs (up to 15k miles) results in less engine wear overall. There are many conditions which need to be monitored when doing this, but it's sound and proven. This is why we're seeing more and more OEMs use their (still conservative) IOLM strategy and not the age-old "3 month / 3k mile" mantra. Data is speaking to those who would listen.

The relationship between clean air, soot loading, TCB, lube filtration efficiency and OCI duration is a VERY complex one. Too many people here want to single it out to one thing, but the reality is that the variability in any one of these causes different resulting reactions in the others.

Engine "longevity" (aka wear) is affected by several things ...
- lube cleanliness levels
- air intake cleanliness levels
- duration of use of lubricant
- tribochemical barrier
- engine design improvements and flaws
- engine manufacturing improvements and flaws
- operational conditions
- environmental conditions
There are so many inputs contributing to the output that it's incredibly hard to say anyone knows for 100% sure what the singular perfect answer is. In fact, I believe it's impossible to claim so, because of the variability of all those inputs. But what we can do is discern levels of improvements which raise the overall data group performance in a statically significant manner (or not, which indicates the hypothesis is proven incorrect).



Here's Jim's article for you to read: https://www.trailerlife.com/tech/diy/the-truth-about-engine-air-filtration/
Here's my article for you to read: https://bobistheoilguy.com/used-oil-analysis-how-to-decide-what-is-normal/
Here's the SAE article for you to read: https://www.sae.org/publications/technical-papers/content/2007-01-4133/
That last article is a real head scratcher. How is dirty oil better at reducing wear than clean oil. Seems to me if that were the case then all of the neglectful owners who barely keep up on oil changes would be getting the longest life out of their engines and would not have worn rings leading to oil consumption vs the guy who is religious with 3-5k changes, but the opposite is the usually the case.
 
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I don't think Ferraris are meant to last as long as normal cars, but what would I know. Engine longevity is the last thing I worry about since a modern engine, when basic maintenance is performed, will outlast the car. At least in the rust belt anyways. I've "flipped" cars for a long time, and have had countless beautifully running engines that were severely neglected. Not saying I'd ever neglect my vehicle, but it goes to show how reliable these engines have become. Transmission and rust, there's your worry.
 
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A lot of parts in this country don't have rusting car issues ... so it makes me laugh when someone says: "Who cares how long the engine lasts because the car will be rusted out before the engine is worn out". I see cars that are 50 years old here that have zero rust on them. Guess in the parts of the country where they salt, etc and cars rust out fast, then might as well neglect the engine too. :D
 
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That last article is a real head scratcher. How is dirty oil better at reducing wear than clean oil. Seems to me if that were the case then all of the neglectful owners who barely keep up on oil changes would be getting the longest life out of their engines and would not have worn rings leading to oil consumption vs the guy who is religious with 3-5k changes, but the opposite is the usually the case.
The article is saying that the AW/AF layer on parts takes some miles (at least 3000 miles) to build up the tribofilm layer that results in less friction between moving parts that are in contact with each other (ie, the "film strength" of the oil). It's not saying "dirtier" oil is better or has less friction. They are saying the engines showed less friction because of the tribofilm AW/AF layer that developed from running the oil at least 3000 miles.

They might have measured the ISO particle count of the oil (would have to see the whole study article). Maybe they also used some high efficiency oil filter to keep the particulate level way down during the test - ?.
 
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The article is saying that the AW/AF layer on parts takes some miles (at least 3000 miles) to build up the tribofilm layer that results in less friction between moving parts that are in contact with each other (ie, the "film strength" of the oil). It's not saying "dirtier" oil is better or has less friction. They are saying the engines showed less friction because of the tribofilm AW/AF layer that developed from running the oil at least 3000 miles.

They might have measured the ISO particle count of the oil (would have to see the whole study article). Maybe they also used some high efficiency oil filter to keep the particulate level way down during the test - ?.
I always had a hard time wrapping my head around that 3K miles for the tribofilm AW/AF layer to be developed. If that were truly the case and changing the oil and adding fresh oil removed the film, then oil running off the parts from an engine sitting over night would have the same impact on parts as changing the oil? I'm not challenging what you posted, I'm trying to understand.

Given a choice I'd rather have clean fresh oil in my engine than oil in service for several thousand miles. Fresh oil isn't going to remove a AW/AF film it would replenish it I would think. I could see a new engine off the line needing some time for the film to build, not a well maintained engine in use.
 
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I always had a hard time wrapping my head around that 3K miles for the tribofilm AW/AF layer to be developed. If that were truly the case and changing the oil and adding fresh oil removed the film, then oil running off the parts from an engine sitting over night would have the same impact on parts as changing the oil? I'm not challenging what you posted, I'm trying to understand.

Given a choice I'd rather have clean fresh oil in my engine than oil in service for several thousand miles. Fresh oil isn't going to remove a AW/AF film it would replenish it I would think. I could see a new engine off the line needing some time for the film to build, not a well maintained engine in use.
It's been discussed in a few other threads. The premise is that the tribofilm that was built up from running the oil for awhile is somehow stripped off to some degree when an oil change is done. It has nothing to do with the engine sitting turned off and the oil draining off the parts. The tribofilm is built-up and stuck to the surface of parts, regardless of how long the oil drains off the surface.

One theory on why the Ford Coyote engine starts ticking right after an oil change is because the previous tribofilm gets stripped off parts with an oil change and the friction level between moving parts increases and triggers some kind of mechanical ticking. The ticking also instantly goes away if an oil friction modifier (like MolyLube CeraTec) is added to the oil, which pretty much points to the friction level as the ticking trigger.
 
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It's been discussed in a few other threads. The premise is that the tribofilm that was built up from running the oil for awhile is somehow stripped off to some degree when an oil change is done. It has nothing to do with the engine sitting turned off and the oil draining off the parts. The tribofilm is built-up and stuck to the surface of parts, regardless of how long the oil drains off the surface.

One theory on why the Ford Coyote engine starts ticking right after an oil change is because the previous tribofilm gets stripped off parts with an oil change and the friction level between moving parts increases and triggers some kind of mechanical ticking. The ticking also instantly goes away if an oil friction modifier (like MolyLube CeraTec) is added to the oil, which pretty much points to the friction level as the ticking trigger.
Hmm, I definitely believe you about the tribofilm, lots of the AW additives require high heat to bond with surface asperities. How long does this process really take though? If I were to change my oil and then proceed to drive 250 miles for 8 hrs straight at operating temperature (which is a normal day for me) wouldn't that be long enough and plenty of heat to bond the tribofilm?


Some engines start getting louder the longer the OCI goes on, specifically the Gamma GDI engine, the older ones pre 2016 would throw knock sensor codes from it. I've only experienced it with Castrol Edge and Valvoline daily protection however. Started making valve train noise, especially on cold starts, after about 3000 miles, was solved instantly by an oil change. Never had the issue with QSUD or M1. My engine runs the quietest the day after an oil change.
 
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A lot of parts in this country don't have rusting car issues ... so it makes me laugh when someone says: "Who cares how long the engine lasts because the car will be rusted out before the engine is worn out". I see cars that are 50 years old here that have zero rust on them. Guess in the parts of the country where they salt, etc and cars rust out fast, then might as well neglect the engine too. :D
That's what the fluid film is for. 😝 Also many modern vehicles come rust proofed from the factory. Even my extremely basic econobox has some sort of rubberized plastic film all over the wheel wells, gas tank, and on the bottom of the runner where the pinch welds are. It's been through three New England winters so far and no rust on the underside, and that's without the FF, next winter it's getting coated. The only issues I've to deal with when it comes to rust is from paint chips on the body.
 
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It's been discussed in a few other threads. The premise is that the tribofilm that was built up from running the oil for awhile is somehow stripped off to some degree when an oil change is done. It has nothing to do with the engine sitting turned off and the oil draining off the parts. The tribofilm is built-up and stuck to the surface of parts, regardless of how long the oil drains off the surface.

One theory on why the Ford Coyote engine starts ticking right after an oil change is because the previous tribofilm gets stripped off parts with an oil change and the friction level between moving parts increases and triggers some kind of mechanical ticking. The ticking also instantly goes away if an oil friction modifier (like MolyLube CeraTec) is added to the oil, which pretty much points to the friction level as the ticking trigger.
Would it be the detergents in the fresh oil that would strip the Tribofilm off? Probably something much more chemically complex I'm guessing. But it would be interesting to know how it happens, if it could be explained in layman's terms.
 
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It's been discussed in a few other threads. The premise is that the tribofilm that was built up from running the oil for awhile is somehow stripped off to some degree when an oil change is done. It has nothing to do with the engine sitting turned off and the oil draining off the parts. The tribofilm is built-up and stuck to the surface of parts, regardless of how long the oil drains off the surface.

One theory on why the Ford Coyote engine starts ticking right after an oil change is because the previous tribofilm gets stripped off parts with an oil change and the friction level between moving parts increases and triggers some kind of mechanical ticking. The ticking also instantly goes away if an oil friction modifier (like MolyLube CeraTec) is added to the oil, which pretty much points to the friction level as the ticking trigger.
Thanks for the explanation. I still have some trouble comprehending it though. I've read the discussions, my thoughts are once the film has built up, it is replenished as it is used up. I'm having a hard time with new oil completely stripping it away to the point of 3K miles of excessive [or to put it mildly increased] wear compared to the oil that was drained, and then taking 3K miles to rebuild the film. How old are these articles? Still an interesting topic though.
 
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If it took that long for the ZDDP to build up an effective tribofilm, most oils would fail the severe engine tests required for qualification, which use new oils in freshly rebuilt engines. I have seen data, albeit from the 70s, that suggested that an effective film was established in the first two hours of an engine test.

Another factor that may contribute to better performance in longer OCI oils is chemical evolution of the additives. For example, back in the 70s a major supplier of jet engine oils noticed that the oxidative stability of used oil samples was better than the fresh oil. It turns out that the two anti-oxidants in the formulation reacted with each other in use and created a new and more potent anti-oxidant. That new AO chemistry is now the main anti-oxidant type in the leading jet oils. Likewise, the anti-wear additive TCP, if hydrolyzed in use, can transform into a partial acid phosphate or nitrogen terminated phosphate which have powerful EP properties.

Lots of chemistry going on in motor oils over long OCIs, so not all wear observations can be attributed to the tribofilm.
 
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Here's a study where it sounds like changing the oil formulation or adding just a base oil removed some of the already built up tribofilm layer and changed the friction level between moving parts.

Source: https://link.springer.com/article/10.1007/s11249-020-01389-4
PDF Link: https://link.springer.com/content/pdf/10.1007/s11249-020-01389-4.pdf

From the Conclusions section:

"Experiments in which the ZDDP-containing lubricant is changed after tribofilm formation by a different ZDDP solution or a base oil indicate that the characteristic friction of the initial ZDDP tribofilm is lost almost as soon as rubbing commences in the new lubricant. The boundary friction rapidly stabilises at the characteristic boundary friction of the replacement ZDDP, or in the case of base oil, a value of ca 0.115. One exception is when a solution containing a cyclohexylethyl-based ZDDP is replaced by base oil. In this case, the boundary friction coefficient remains at the high value characteristic of this ZDDP, despite the fact that rubbing in base oil removes about 20 nm of tribofilm."
 
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I am currently running another 3 year experiment to test this theory again. In the 812 Superfast I will soon analyze the 5W-40 Ferrari spec’ed oil. Then I will run a 0W-30, then maybe a 0W-20. The final leg will be the original oil and viscosity. In all unfairness I will not be taxing the oils the same. I have always waited for the thicker oils to come up to full temperature before running around the town with bursts to redline. Currently 170 - 175 F to 9,000 RPM.
entertained.jpeg


Even water can be used as a lubricant. This is partly because of its high surface tension.
@AEHaas Only if you try it first, I'm sure we'll follow your example! (y)
 
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