UOA article - what is "normal"

The SAE paper (2007-01-4133) specifically notes that there is a vis increase, and that increase is non-detrimental at the valve train. However, it also acknowledges the concerns of fuel economy from parasitic drag in the cylinder, where surface area affected by vis is much greater than at the valve train.

In short, it's a balancing act.

The thing I'm trying to get across to people is that shorter OCIs generally are a total waste of money. You don't "gain" any wear reduction; you actually increase wear in shorter OCIs. While it may be counter-intuitive to the layman, it makes sense when you see the studies and data.

There are certainly times when shorter OCIs are warranted; heavy contamination or sludge. But those are not nearly as common as some believe, and I have always excluded such examples from my generalizations. I would NEVER suggest extending an OCI when there is a known problem that cannot be mitigated without phsical intervention, or stalling with OCI frequency. And that is really what it's all about; you have to KNOW your equipment, and your lubes, to really understand what is good/bad decision wise. Too many people here blindly take a "kitchen sink" approach; they throw everything at the lube interval (short OCIs, syns) and call it "good" and they have no idea how define acceptable condemnation limits, and are unaware of how far out even conventional lubes can successfully go.

As I've said (and it's in my signature line) ...
ANY lube can be over or under utilized.
 
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Fantastic article, thanks for sharing.

This is why i use Mobil Super 5000 or PYB 5W30 conventional in my Mitsu Lancer Ralliart Turbo. The vehicle is a daily driver (no modifications, no track use, very rare spirited drive). Now, because it is a turbo, and under powertrain warranty, i subscribe to a 3750 f/oci. There are huge battles on the Turbo forums between conventional vs synthetic oil users. I am not saying that conventional is better, it isn't. But also isnt neccesary for my application, oci or driving style. Mitsubishi and all the major oil giants list conventional 5w30 as the requied oil. I just make sure it meets API SN, GF-5 ILSAC.


Again, thanks for sharing.
 
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Dave, I was doing some thinking about the deposition of anti-wear films with respect to the oils we see now compared to what was seen a couple decades ago. Now we see that the anti-wear protection does better much further into the OCI. I'm wondering how much of that is due to the lower ZDDP oils we see. Also, we certainly see some very high ZDDP applications for break in lubes. I'm just wondering how things might have compared back in the day, with, of course, some consideration of the fact that oils were much poorer back then, too.

As an aside, I do think we place too much stock into how much ZDDP was in the older oils. Some certainly had some high levels, but a lot of them (check Blackstone's articles) had the same as PCMOs today, or even much less. Back then, ZDDP content was a bit of a gamble, even with the top brand oils. Today, at least, you know you're going to get in the neighbourhood of 750 ppm, with few exceptions.

Just because the phosphorous limits didn't exist back then didn't mean oil companies made sure all oils had 1400 ppm ZDDP, either.
 
When reading the SAE study they mention there are actually several different types of ZDDP compounds that can be used. The chemical make-up of the ZDDP does indeed affect the anti-wear layers. It also disucsses the affects of detergent packages reacting with the ZDDP and having a negative affect on the anti-wear layer.

Ryan Start (Blackstone) ran an oil in his truck that had zero ZDDP whatsoever; the package was formulated in alternative ways. I think it was an aero-oil, IIRC. Anyway - after a couple short OCIs, there was no abnormal wear due to the lack of ZDDP. The wear that was present was due to two things:
1) the old 350 GM simply is a high-wear engine to begin with (see proof in my article)
2) the engine was a new rebuild - break in was occuring

So the "need" for ZDDP is greatly overblown in his opinion, and in mine. Wear can be attenuated by a large multitude of methods; ZDDP is just one of them. And while "ZDDP" is a description of an anti-wear additive, it tells us nothing of the actual sub-chemical composition. The nuiances really matter, as to the formation (or destruction) of the anti-wear layer.


Of course, getting the bulk of BITOGers to acknowledge this is difficult. And getting them to actually agree to it is nearly impossible. Regardless of how much proof (SAE study and Stark's example) one lays down. The oil bigotry runs deep here; long, wide and deep. Despite the facts.
 
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Well, one thing about the old small blocks, you could throw all the ZDDP at them you wanted to, of whatever chemical makeup, and it would eat cams anyhow.
wink.gif


As for detergent packages, I suppose that's one reason why certain racing oils have little to no detergent and a boat load of zinc. As for me, I'd rather run an oil with some ZDDP (as opposed to some aero oil), but I'm not seeing the ZDDP levels of older oils with rose tinted glasses, either. The only "dated" oils I can think of that would have guaranteed high levels of ZDDP were some of the older spec dual rated HDEOs. For the rest, oil companies figured out long ago they could cut phosphorous from the oil and save some cash without API/ILSAC telling them to do so.
 
So, barring any problems with the engine - and I KNOW each case is different, but just for the sake of a blanket statement, a guy could run a conventional out to typical synthetic oci's (~10k range) without much cause for concern, pending that his engine was in good shape and the oil was a name brand...?
 
I am very interested in the "wear versus miles" analysis you performed, as a misunderstanding of this can be the basis for claims about oil quality and wear. From looking at your data presented, it seems that you could perform a regression analysis on your data to model the slope. This may provide a "wear rate" that is informative and distinguishing among oils or applications. This might also define an endpoint for an oil by identifying an inversion point on the slope. Further, examination of short-interval data across multiple changes (a paired analysis of data) may show an average initial rate due to tribochemical reaction with the new material. If this is truly wear (the metal has to come from somewhere) it would seem that a goal of lubricant design would be to reduce that initial wear rate.
 
I read your article late last year when I had just found this site and knew very little about the things we discuss on bitog. I just read it again and have much more appreciation for it now. I plan to make use of the info (the best I can), although I still have a lot to learn.

Thanks Dave !
 
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