What is the best oil ingredient to protect against cold start wear?
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At around 7:04 in the second video, he says the cold oil is cloudy and won't flow because it contains wax. Are they using a conventional oil, because aren't synthetics supposed to be completely wax free? I know he mentions the 0W30 in the first part of the video is a synthetic blend.
OVERKILL
$100 Site Donor 2021
No, the only petroleum base that's wax-free is PAO.
Is a PAO base better than a GTL base?
An advantage of PAO is better low temperature performance and much lower pour points, like -60°C vs. -20°C, of the base oils. Pour point depressants though aren't the most problematic additives to care about and the formulated oils end up in pp like -58°C vs. -54°C or -45°C. PAO help to attain the lowest winter grades with low enough viscosities.
This is usually not from much wax in other modern synthetics along the sensible definition of wax (~something at more civil temperatures) which needs to be distorted these ways to find much wax in them by regarding deep frost as the new ambient.
Other base oils perform more like GTL (with even better VI but still some pour point like -20°C) although they aren't even paraffins / alkanes like PAO, GTL, XHVI, WBASE etc. It's bogus to operate with the misleading wax term this way. PAO in this regard have their main advantage over GTL, Estolides or whatever and this performance can be compared (or that of formulated products). Compared without much sense in the waxy talk. Or are we going to talk about wax in BT4 around -20°C and wax in PAO around -70°C? Indign...
This is usually not from much wax in other modern synthetics along the sensible definition of wax (~something at more civil temperatures) which needs to be distorted these ways to find much wax in them by regarding deep frost as the new ambient.
Other base oils perform more like GTL (with even better VI but still some pour point like -20°C) although they aren't even paraffins / alkanes like PAO, GTL, XHVI, WBASE etc. It's bogus to operate with the misleading wax term this way. PAO in this regard have their main advantage over GTL, Estolides or whatever and this performance can be compared (or that of formulated products). Compared without much sense in the waxy talk. Or are we going to talk about wax in BT4 around -20°C and wax in PAO around -70°C? Indign...
One more interesting clip by the way: https://www.exxonmobilchemical.com/...6142/synthetics_technical_video_solubility_en
An insider (of course I can't remember its name) once told me they could easily make their oil candles wax-free if only the customers wouldn't prefer them standing tall upright nearer to thee near the pour point.
An insider (of course I can't remember its name) once told me they could easily make their oil candles wax-free if only the customers wouldn't prefer them standing tall upright nearer to thee near the pour point.
OVERKILL
$100 Site Donor 2021
It's just a different base and so has some advantages and disadvantages. PAO's primary advantages are improved oxidation resistance and superior low temperature performance but low temp performance of Group III bases can be greatly enhanced with only a small amount of PPD's. It's disadvantages include poor additive solubility, requiring another base that's better in that department be blended in, like an Ester. Here are the properties of Mobil's main synthetic base oils:
And some "typical properties":
Some Group III slides from a few presentations, one from SK who makes Yubase:
And some specific properties of Shell's GTL bases:
So, if you compare the SpectraSyn products to the GTL ones, you can see the pour point of PAO is clearly much lower, since it has no wax in it. Specifically, if we look at SpectraSyn 5 for example and compare it to GTL 5, PAO clearly stands out in a few ways: CCS is better, pour point is lower, Noack is lower, flash point is higher:
OVERKILL
$100 Site Donor 2021
Two more slides from the SK presentation touching on two things:
1. The quest for improved fuel economy in EC requirements like GF-4 GF-5...etc has been one of the main reasons for improving base oil blends in PCMO's:
2. Traditionally, it has been difficult to blend low volatility 0w-20/0w-30's using Group III, I believe this is exasperated in higher spread oils like 0w-40, which is why we often see
PAO in the Euro 0w-40's and 0w-30's because it's needed to keep Noack within limits while still meeting CCS/MRV requirements. With GTL offering incremental improvements in both those areas, the need for PAO is either reduced or wholly eliminated as per Shell's current crop of products.
1. The quest for improved fuel economy in EC requirements like GF-4 GF-5...etc has been one of the main reasons for improving base oil blends in PCMO's:
2. Traditionally, it has been difficult to blend low volatility 0w-20/0w-30's using Group III, I believe this is exasperated in higher spread oils like 0w-40, which is why we often see
PAO in the Euro 0w-40's and 0w-30's because it's needed to keep Noack within limits while still meeting CCS/MRV requirements. With GTL offering incremental improvements in both those areas, the need for PAO is either reduced or wholly eliminated as per Shell's current crop of products.
Practically all posts pertaining to start up wear have been locked (weird) so I found this one.
Amsoil's site basically agrees with Mobil that most wear does occur at startup.
This is from 12/2023 via Amsoil:
"Engineers agree that most engine wear occurs during cold starts. While the exact percentage depends on several factors and is difficult to define, the reasons include the following…" - Amsoil Inside Track News.
Mobil:
Amsoil's site basically agrees with Mobil that most wear does occur at startup.
This is from 12/2023 via Amsoil:
"Engineers agree that most engine wear occurs during cold starts. While the exact percentage depends on several factors and is difficult to define, the reasons include the following…" - Amsoil Inside Track News.
Mobil:
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dnewton3
Staff member
Engineers like me want to see the raw data, and understand the conditions under which the tests were run, before believing claims like this.
Far, far too many times I've seen heavily biased testing results become popularized, when no real world data exists to back up the claims. Especially when the claims come from Amsoil.
For example, Amsoil famously regurgitates the whole "use a better filter" mantra by citing the infamous GM filter study from a few decades ago; that filtration study was horribly misleading to the general public in its conclusions. The conditions under which the testing was done would NEVER EVER IN A LIFETIME exist in the typical operation of a normal vehicle. And yet that study is quoted ad nauseum by Amsoil and other entities as a reason to upgrade filtration.
And I doubt Amsoil did any real testing for start-up wear. They probably are parroting a rosey conclusion from some other study that is also grossly biased.
Hence, my belief in the data wanes.
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Here's why I say this is total bovine scat ...
Most all of us drive a fairly "normal" life. We start and use our cars with a fairly regular schedule; our routines don't vary much. For example, in a 7k mile OCI, we go to work, drive home from work, and run typical errands or take weekend trips, etc. The start-up cycles don't vary greatly in the overall operation of our engines relative to the operational time. IF the "startup wear" claims by Mobil and Amsoil are true, we would make a reasonable assumption that because our driving patterns don't change much in the macro scale, then the wear trends should stay steady.
But ... That's not at all what happens. There are SAE studies which show wear trends declining as the OCIs mature. And my 35k UOAs echo the same trends. This isn't one or two UOAs; it's literally THOUSANDS UPON THOUSANDS of UOAs from all manner of engine applications which show that as the OCI matures, the wear rates decline. For the "70% start-up wear" claims to be true, and still live within this proven declining wear phenomenon, then that would mean ALL of us are driving every longer cycles (fewer starts) as our oils age. And then by some miracle, we start driving shorter cycles when we OCI, and lengthen them, in a repeated fashion.
The "70% wear at startup" claim is total poppycock; it simply cannot coexist with the REAL WORLD data from just about every normal engine UOA we know of that we see.
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MolaKule
Staff member
Minor wear on startup theoretically can occur but I have yet to see a study which shows micrograms of metallic loss or wear verses temperature verses time.
Since the introduction of various hexagonal Boron nitrides (h-BN), Titanium oxides (TiO2), or Tungsten Nitrates/Nitrides suspended in an ester (that tend to make good cold start anti-wear compounds before oil temps rise to activate ZDDP films), I don't see cold-start as something to worry about.
It seems people forget that at shutdown an oil film with its additives are still present on metallic parts.
There are two studies I'm aware of that measure piston ring wear during engine warm up in real time with a radioactive tracer technique. SAE 952474, and SAE 2006-01-3413.
Both studies show wear rates around 20 times higher than baseline for at least several minutes during engine warm up. Neither study indicates that any of this wear is due to the initial starting conditions of the engine, i.e. "start-up". The earlier study routinely uses the term "start-up wear", and I think this term causes a lot of confusion. The accelerated wear doesn't occur at start-up. It occurs as the engine is operated throughout the ~20 minute warm up period.
The authors of the studies didn't speculate as to what is causing this phenomenon. I suspect it's due to poor piston-liner clearance during warm up. Pistons will heat up faster than block, and they also expand more since they're aluminum (both studies used iron-block engines). This reduces the clearance between the piston and liner until the engine block gets up to temperature.
Rich A/F ratio on cold start-up can also do some "fuel wash down" in the cylinders and impact oil lubrication. Depending on how cold the start-up is done at, cylinders and rings may have a momentary lack of splash lubrication depending on engine design, even if the right W rating is used. It would be interesting to see a test of the impact of piston oil squirters on the cylinder/ring wear at cold start-ups.
A good oil filterWhether it's an additive, or a certain type of base stock, or both.
Titanium? Moly? "Intelligent molecules?"Etc...
To add, think about those engines that are known bad fuel diluters. In those engines I would think there is more cylinder fuel wash down going on than in an engine that's not a big fuel diluter. In another thread, someone claimed Honda engines were "tearing up rings" badly from using xW-30 instead of xW-20 oil, but thinking about this it could be the rings wore out early was from major fuel dilution.
I think that's a good theory. Fuel dilution rates are much higher at high load and rpm, and this is also when piston ring wear is naturally high. Add cold cylinders into the mix and it seems like it would be a perfect storm for piston ring and bore wear. I wonder if those Honda issues are more common in cold climates.
Looking a bit closer at the chart I posted, it takes a couple of minutes after start up for the wear rates to start increasing, indicating some measurement delay. From there, about half of the total wear during warm up occurs within about 1.5 minutes. Immediately after start up the piston-bore clearances would actually be larger than at operating temperature. This might make dilution worse.
It's also hard to rule out the possibility that most of the wear during warm up actually occurs due to the conditions that are present within the first few seconds. Some other studies show that high wear rates can continue for some time even after the cause of the wear is eliminated (abrasive dust for example), though I don't know if this would be the case here. Maybe a lack of lubrication in the first few seconds after start up really is causing a lot of this wear.
I have taken apart engines that sat for 20 years, there was still plenty of oil up in them.
See above post