In the parts of the world where ACEA is the primary standard for motor oil 10W-40 and 15W-40 synblend are common.
Does conventional offer the same protection as synthetic?
- Thread starter AlphaOmega
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I would say, Yes, it will on older cars & modern engine as well (not recommended for S/C, Turbo or High performance engines) but your OCI will be limited to 5K miles or less. Because of the price of synthetics went down that is why you don't normally see them anymore. There are million miler cars out there that were ran exclusively on conventional motor oil
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Excuse my obtuseness please, but as I understand - for now - a synthetic is more durable and stout, but, until conventional, as in your example, thickens due to oxidation, the protection against friction/wear it offers is the same as with synthetic... Right? If one changes conventional often enough, one gets 99.978% protection as with synthetic?
Would a bottom line summarization that, for the most part, synthetic oil is more durable/longer lasting, but otherwise is NOT inherently better at "film strength", "film thickness", "lubricity", etc vs synthetic be correct? Thanks
The anwer is : Yes, no, maybe and maybe not
You keep stating stuff that isn’t important. As noted, wear isn’t an issue with any fully formulated motor oil. Besides, measuring comparative wear between motor oils is a complicated and expensive proposition.
And where are you pulling 99.978% from? The air? These types of statements are unhelpful in the discussion.
And again, lubricity and film strength are not properties of motor oils used in an ICE. Note that no manufacturer or blender reports values for either one nor is it relevant.
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@kschachn, mate your statement "wear isn’t an issue with any fully formulated motor oil" answers my original question and it matches what Astro14 moderator said to me in private message. Just wanted to see if the other member that gave an expanded answer would converge on it as well.
The 99.978% just means nearly certainly, same as your statement "wear isn’t an issue with any fully formulated motor oil", because I'm sure there are exceptions
The 99.978% just means nearly certainly, same as your statement "wear isn’t an issue with any fully formulated motor oil", because I'm sure there are exceptions
Providence Automotive (Rural King house brand) sells what they call conventional motor oil. It’s $14.49 for a 5 quart jug. SP rated.
They sell Mobil Super synthetic blend for 50 cents more.
https://www.ruralking.com/catalog/product/view/id/181855
Maybe. Oil formulations could very well be different than today, but hopefully this data will be helpful. These reports were from a 2004 Jeep 4.0, and I was driving over 20k miles (~32000 km) per year at the time so testing a 5k interval was easy. This was in temperate Southern Virginia climate.
Based on this series of reports, VWB did as well or better than M1, Amsoil and ST Syn.
12/15/2011 was SS 5w30
10/27/2011 was ST Syn 5w30
07/31/2011 was VWB 5w30
04/22/2011 was M1 AFE 0w30
Earlier reports were older stock of Amsoil 10w30 that I was using up.
Based on this series of reports, VWB did as well or better than M1, Amsoil and ST Syn.
12/15/2011 was SS 5w30
10/27/2011 was ST Syn 5w30
07/31/2011 was VWB 5w30
04/22/2011 was M1 AFE 0w30
Earlier reports were older stock of Amsoil 10w30 that I was using up.
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Bingo! This should be embossed on the foreheads of those who suggest that "oil is oil" and that any oil that "meets the spec" will behave similarly, and that using anything more than the cheapest oil that meets the spec is a waste of $$$.
No.
Sure but like I said for me at least conventional would be free gr 3,4 or 5 and I doubt this RK product could reach API SP on Gr2 alone let alone A3/B4 (OP was interested in).
So that we are clear - I wasn’t asked to be a moderator because of my oil expertise.
There are many members on the board who know a great deal more than me.
Two of them, @OVERKILL and @kschachn, are answering your questions, and while I’m gratified that my perspective is similar to theirs, they are the ones to whom you should be listening.
Cheers,
Astro
They say a picture is worth a thousand words. Here's one from a 2000 Century which was very well maintained by the original owner, my father. OCIs were every 3,000 miles, dino oil. The car had no mechanical issues with the engine whatsoever at the time this picture was taken. Miles on the car at the time were ~80,000. I wasn't impressed with the dino oil's ability at all to keep that engine clean. I can only imagine what it would have looked like with 5,000 mile OCIs.
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That doesn’t look good at all. It even looks slightly milky in the bottom pic but that may be the lighting.
dnewton3
Staff member
To answer the question, I'll put some bounds to the conditions for a more accurate view ...
- Assuming the two oils (conv and syn) are reasonably modern and not "old stock" from decades ago.
- Assuming the engine application is not a known sludger, or a shear-monster, has known mechanical flaws, etc.
- Assuming the conditions of operation are "normal" and not uber extreme (below 0 degF; drag racing cycles in AZ; etc)
- Assuming the maintenance plan is "normal" 3k miles with a decent filter (can often go further than 3k miles, but that is the OPs quest here)
- Assuming we're not going to nit-pick the word "synthetic" and just accept that it could refer to a grp III, IV or V. (a worthy topic for a different day)
Generally, the answer would be "yes", a conventional oil will provide the same wear protection as a syn.
Wear protection comes from three things:
1) tribo-chemical barrier
2) MOFT
3) additive package
I cannot state which of those three are most important; I believe they all three contribute to an overall measure of success, and to the best of my knowledge, there has never been an SAE or other credible study that has isolated one relative to the others for a determination. But rest assured, the three attributes combine to make for wear control.
I have personally run OCIs out to 10k miles in 4.6L Ford engines, and seen absoblutely zero wear differences between conv and syns:
https://bobistheoilguy.com/forums/threads/5w-20-ford-4-6l-engines-uoa-testing.269435/page-3
That does not mean it will always be true; it was true in this case because the assumed conditions I stated were true. This is just real-world annecdotal proof that the claim is real, if the conditions are right. (NOTE: Individual UOAs will always have some variability; always use statistical data norms for your comparison and contrast limits.)
I also have around 30k UOAs in my database; so many now that I've stopped collecting them. I can say with absolute certainty that if the assumed conditions are true, the answer is an emphatic "Yes" - conventional oils will protect as well as syns. I've studied these UOAs until my eyeballs ached, and I can say unequivically that if the assumed conditions are in place, you would never be able to tell a syn from a conventional oil in terms of wear control.
- Syns are superior at holding their vis in range, but that ONLY is a benefit if the conventional oil has been used long enough that it goes severly out of range; probably never going to happen in a 3k mile OCI.
- Syns are superior at cold start pumpability, but that NEVER is a benefit if it's not uber cold outside.
- Syns are superior at oxdiation control, but that NEVER is a benefit if the engine does not overheat, because "normal" expected operational temps are not a problem for conventional oils. (Note: some oxidation is good; it's what builds the TCB layers; SAE 2007-01-4133)
Further, syn lubes are not immune to severe conditions either. Yes, syns can endure some conditions better than a conventional oil, but you absolutely run a syn oil for too long of an OCI. A syn most certainly can shear. A syn can degrade with heat. A syn can have it's additive package overwhelmed with contamination and degradation just like any conventional oil. Typically, it just takes "more" of the offensive condition to make a syn fail relative to where a conventional would fail.
Syn lubes ONLY have an advantage over a conventional oil IF some condition experienced makes the convetional oil fail first. Given the stated assumptions, that would never be true, and therefore the logical and truthful answer is that you'd never see a difference in wear control or even cleanliness for that matter.
- Assuming the two oils (conv and syn) are reasonably modern and not "old stock" from decades ago.
- Assuming the engine application is not a known sludger, or a shear-monster, has known mechanical flaws, etc.
- Assuming the conditions of operation are "normal" and not uber extreme (below 0 degF; drag racing cycles in AZ; etc)
- Assuming the maintenance plan is "normal" 3k miles with a decent filter (can often go further than 3k miles, but that is the OPs quest here)
- Assuming we're not going to nit-pick the word "synthetic" and just accept that it could refer to a grp III, IV or V. (a worthy topic for a different day)
Generally, the answer would be "yes", a conventional oil will provide the same wear protection as a syn.
Wear protection comes from three things:
1) tribo-chemical barrier
2) MOFT
3) additive package
I cannot state which of those three are most important; I believe they all three contribute to an overall measure of success, and to the best of my knowledge, there has never been an SAE or other credible study that has isolated one relative to the others for a determination. But rest assured, the three attributes combine to make for wear control.
I have personally run OCIs out to 10k miles in 4.6L Ford engines, and seen absoblutely zero wear differences between conv and syns:
https://bobistheoilguy.com/forums/threads/5w-20-ford-4-6l-engines-uoa-testing.269435/page-3
That does not mean it will always be true; it was true in this case because the assumed conditions I stated were true. This is just real-world annecdotal proof that the claim is real, if the conditions are right. (NOTE: Individual UOAs will always have some variability; always use statistical data norms for your comparison and contrast limits.)
I also have around 30k UOAs in my database; so many now that I've stopped collecting them. I can say with absolute certainty that if the assumed conditions are true, the answer is an emphatic "Yes" - conventional oils will protect as well as syns. I've studied these UOAs until my eyeballs ached, and I can say unequivically that if the assumed conditions are in place, you would never be able to tell a syn from a conventional oil in terms of wear control.
- Syns are superior at holding their vis in range, but that ONLY is a benefit if the conventional oil has been used long enough that it goes severly out of range; probably never going to happen in a 3k mile OCI.
- Syns are superior at cold start pumpability, but that NEVER is a benefit if it's not uber cold outside.
- Syns are superior at oxdiation control, but that NEVER is a benefit if the engine does not overheat, because "normal" expected operational temps are not a problem for conventional oils. (Note: some oxidation is good; it's what builds the TCB layers; SAE 2007-01-4133)
Further, syn lubes are not immune to severe conditions either. Yes, syns can endure some conditions better than a conventional oil, but you absolutely run a syn oil for too long of an OCI. A syn most certainly can shear. A syn can degrade with heat. A syn can have it's additive package overwhelmed with contamination and degradation just like any conventional oil. Typically, it just takes "more" of the offensive condition to make a syn fail relative to where a conventional would fail.
Syn lubes ONLY have an advantage over a conventional oil IF some condition experienced makes the convetional oil fail first. Given the stated assumptions, that would never be true, and therefore the logical and truthful answer is that you'd never see a difference in wear control or even cleanliness for that matter.
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I would have gladly agreed IF you had avoided using the word NEVER.
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I would have gladly agreed IF you had avoided using the word NEVER.
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