Proof that re-refined oils are a 'stronger' oil?

[addyguy]

A couple of posters at different times on this board have speculated that re-refined oils may be better than 'virgin' oils b/c the process starts out with oils that have already been processed, so by re-processing them, you get out even more unstable junk and end up with a stronger oil.

A lot of people tended to disagree, saying there is no guarantee that the oils are put through as stringent a processing the second time around, so you may or may not end with as good of a product.

I think I may have found a bit of proof that these oils may in fact be more shear-resistant than group II or even III oils. Take a look at this UOA:

http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=3;t=000882#000000

After 5000 miles, the viscosity of this oil was still 10.4, comfortably in the range of 30-weight oil. Now before saying this engine is easy on oil, take a look at these other two UOA's:

http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=3;t=003137#000000

http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=3;t=000693#000000

In the first one, this engine sheared a syn blend to a 20-weight (last column). In the second one, the same engine sheared a group III syn. to a 20-weight as well. I know this is just one UOA that doesn't show shearing, but it is pretty impressive comapared to the other two.

The whole point of this post is that there are a few people on this board who don't like the way dino oils shear out of grade, and the general thought is that the only way to avoid this is to go to much more expensive synthetic oils. Maybe using re-refined oil is a way to achieve this end cheaper?

Another complaint about re-refined oils is that they tend to be sold at the lower end of the scale, and so the add packs are not as strong as they could be. Maybe a re-refined oil with something like VSOT, #132, or SX-UP is the way to a cheaper, shear-resistant, high-performance oil....?

I know subjectively, I used Tech 2000 5W-30 in my Cavalier for 6500 km's, and the car 'felt' much smoother for the whole oci.

 

[Ray H]

I can (and do) believe filtered and severely hydrotreated "re-refined" oil delivers a base oil fully the equal of like processed virgin crude petroleum. But, superior? I'm afraid that's a stretch I'd have to see verified evidence of. You know what they say about opinions and noses. (This politer version graciously offered to conform to the site's Big Brother thought police dictums...

)

[ July 11, 2006, 02:42 PM: Message edited by: Ray H ]

 

[pitzel]

Well maybe because a proportion of the population uses (and recycles) synthetic oil, that the overall percentage of synthetic components in 're-refined' oil is greater than the low concentrations of synth you would find in a traditional bottle of dino.

 

[Pablo]

I see no solid proof that recycled oils are better, stronger, but yours is a good observation.

It sorta gets my juices going - we could design a great oil. Previously owned oil and synthetic blend with top notch add pack at a resonable cost while saving Al G....er the earth!

 

[bruce381]

re refined base stocks now day from evergreen or saftey clean or mohawk are at best GPII with VI about 105.

Base stocks in general DO NOT contribute to "shear" vis loss.

Unless you have a baseline Vis from a test oil as far as you know that syn blemd may have been at 9.5 cSt on grade for a 30wt.
Fuel dilution also will impact vis.

That said shear loss is due to VII.

Some brands will use less VII or a lower shear stability index VII and will show less shear loss.

re refined as well as virgin base stock type do not really enter into the shear equation at all, VII and perhaps add pak do.

There is some IMHO small percent of GPIII and PAO now in re refined oils due to the upgradeing
of all PCMO and HDEO's but does not make a big difference in shear stability or VI.

bruce

 

[bruce381]

"It sorta gets my juices going - we could design a great oil. Previously owned oil and synthetic blend with top notch add pack at a resonable cost while saving Al G....er the earth!"


Being done now by small guys and majors they just do not tell you.
bruce

 

[ekpolk]

Perhaps these products make sense in a large, high-mileage fleet context, but I just don't see the point from an individual car-owner perspective. The largest automotive sumps rarely exceed seven quarts or so (usually considerably less), therefore, the cost savings are marginal at best. I think re-refined oils would probably work fine in most cases, but I still don't see any reason to try them myself. Then there's always the chance that the product is not actually properly or completely re-refined -- something I'd very much prefer to avoid finding in my engine.

Pass, thanks.

 

[bighead]

Just thought of something. Everyone is in agreement that all SM/GF4 oils are good, and that there are no "bad" ones, due to the fact that they HAVE to be good to meet this spec, right? Well, is there some spec that re-refined oils have to meet to ensure they get re-refined properly?

I agree with ekpolk when he says he'd rather not take the chance of putting a bad batch of the re-refined stuff in his engine.

 

[bulwnkl]

If the re-refined oils are labeled as SM/GF-4, then that's the spec they have to meet, just like the once-refined stuff. If you think about the feedstocks that go into re-refined oil vs. once-refined oil, and think about what might go wrong when/where, why is re-refined oil more scary than once-refined? Personally, I think used PCMO/HDMO is less scary as a crankcase fill than crude oil... but that's just me.

 

[bighead]

quote:

---

Originally posted by bulwnkl:
If the re-refined oils are labeled as SM/GF-4, then that's the spec they have to meet, just like the once-refined stuff. If you think about the feedstocks that go into re-refined oil vs. once-refined oil, and think about what might go wrong when/where, why is re-refined oil more scary than once-refined? Personally, I think used PCMO/HDMO is less scary as a crankcase fill than crude oil... but that's just me.

---

Oh, ok. I've actually never seen a bottle of the re-refined stuff, so I didn't know if there were specs listed on it.

 

[Gilitar]

quote:

---

Originally posted by bulwnkl:
If the re-refined oils are labeled as SM/GF-4, then that's the spec they have to meet, just like the once-refined stuff. If you think about the feedstocks that go into re-refined oil vs. once-refined oil, and think about what might go wrong when/where, why is re-refined oil more scary than once-refined? Personally, I think used PCMO/HDMO is less scary as a crankcase fill than crude oil... but that's just me.

---

I completely agree with your logic regarding re-refined vs once-refined. I don't believe that I have ever seen re-refined oil in the store however.

 

[Bryanccfshr]

[/qb][/QUOTE]I completely agree with your logic regarding re-refined vs once-refined. I don't believe that I have ever seen re-refined oil in the store however. [/QB][/QUOTE]


Most likely you have seen it. The Base stock could be purchased by any blender. Does your bottle of oil say "Virgin" ??