10W vs 10W-30 vs SAE 30 cylinder wear

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Sure it does when was the last time you say a 10W40 or 5W40 with an additive package like a 5W20 or 0W20 have... I am talking regular off the shelf oil in North America not Redline or some other mail order oil!!! If it is not on the shelf at Walmart it does not count!! SInce Walmart is the largest retaileringint he world it is fair to use them as the standard.... Now if you look at Havoline 5W20 and then look at Havoline 10W40 or 20W50 you will seee what I mean!!! Just look at how much moly almost everyone put'sint heir 5W20!!!!! You do not see 200+++PPM of moly in Havoline 10W40,5W40,or 20W50! So my statement makes perfect sense!!!Then you have the percentage of of GI,GII,GIII,IV,V etc..... I belive I mentioned 10W40 not 5W30 G-Man so do tell me what brand of 5W20 has identical base stock amounts of each group in common between a companies 5W20 and 5W40 or 10W40 etc....I did not compare 5W20 to 5W30 G-Man for this very reason....

Any time you want a companies dino oil with the most additives it is almost a gurantee that their 5W20 will have the most additives of any of their dino oils!!!
 
Too bad that article doesn't have a copyright/publication date on it. It's definitely been a while since "Mr Ordiway" wrote it, and Kendall hasn't advertized the "Pennsylvania Crude" thing for a while now!
 
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I just noticed - those cylinder wall temps are in CENTIGRADE!
Holy Moly!
I don't think a water cooled car engine will approach those temps when the cylinder wall is surrounded by coolant.
 
Originally Posted By: mechtech2
I just noticed - those cylinder wall temps are in CENTIGRADE!
Holy Moly!
I don't think a water cooled car engine will approach those temps when the cylinder wall is surrounded by coolant.


Apparently they do, since this was a Mercedes diesel engine.
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Quote:
Do these UOA's with synthetic SAE 30 (Amsoil ACD) not show less than average wear?


In those UOA's, yes I would say wear was reduced. I'd like to see more UOA's between straight grade vs multi grade.
 
Originally Posted By: il_signore97
I was just wondering, after all this talk about the potential merits of a straight SAE 30 oil due to its VII-free construction and inherent shear stable design, it seems as though it's an excellent choice for many people during seasons that do not dip into the extreme cold temperatures.

But, how does a high quality SAE 30 oil (such as Amsoil ACD HDEO SAE 30 for example) compare to an equally high quality, fully synthetic 0W30 such as Amsoil's Signature Series (SSO)? The SSO has a HTHS value of 3.2, and likely has a lower amount of VII's than nearly all conventional 5W30 or 10W30 oils. The SSO is supposedly a very shear stable formulation, even moreso than the TSO that it replaced.

So, for the same reasons that an SAE 30 is likely a good oil choice (since no VII's and high shear stability), shouldn't the performance of a highly shear stable and low VII 0W30 be nearly as good, if not equal to any good SAE 30?

Just curious! Thanks
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Back in the 60's and early 70's, (I know that's along time ago) we would use 20w-40 or straight 30 or 40 in patrol cars because the 10-30 or 10-40 would break down under hard acceleration. Don't know if that would be true with today's oils.
 
Originally Posted By: G-MAN
The SAE paper the following graph is from has been discussed in the aviation forum before. It shows the relative cylinder wall wear vs temp for straight 10W, 10w30, and straight 30.

Keeping in mind that this is just cylinder wall wear, I was still surprised that 10W and 10w30 didn't perform better at low temps. But the real surprise is just how flat the wear curve is for SAE 30.

Maybe the oils companies do know what they are talking about when they put something like the following in the PDS for straight grades: "Valvoline SAE 30, SAE 40, and SAE 50 offer excellent protection to gasoline engines operating under high temperature and heavy-duty service (hauling trailers, boats or RVs for sustained periods).

SAE082807.jpg



I understand the high temp effect.
But why the low temp effect? ZDDP not active at those temps?
 
No takers?
This is what I'm thinking:
The increased wear at sub 80C temps is caused by unburnt fuel and combustion byproducts condensing on liners and diluting the oil lubricating ring/liner interface. Such dilution decreases viscosity and contributes to warm-up wear. Thicker oils will resist that viscosity break down.

If so, a very complex picture of viscosity vs wear emerges.

Here is my hypothesis:
1. Cold starts at subzero conditions: 0WX and 5WX oils, especially synthetic and PAO-based have big wear advantage due to faster flow.
2. Cold starts at zero plus conditions and warm-up: thicker oils offer wear advantage (straight 30 in the above example).
3. Near 100C oil temp: low steady state wear, oil viscosity not critical.
4. Hot oil, 130C and higher, HTHS critical with increased wear below a given HTHS minimum (2.6 at 130C as we know from other studies).
 
how do you even measure cylinder wear at cold temps? turn it on and shut it down when it reaches x temp? then start again when it's cold? what rpm? DO av engines have different clearances? they're air cooled
 
T5 10w30 should do for severe service this summer.. be nice to measure cylinder temps to know for sure.

Not sure I would go with a straight 30 weight, but this is interesting nonetheless.
 
I don't believe that chart.
It makes no sense that at normal operating coolant temps of 192-210 a 10 is insanely horrible for wear.
Extrapolate the graph , and the wear for the 10 and 30 is never going to stop - it could not reach temp. The engine would wear away before operating temp is achieved!
 
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