It was mentioned in this thread that synthetic oils have a superior film strength compared to their conventional counterparts; your comments on that declaration please.
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Do synthetic oils have a superior film strength?
- Thread starter Merkava_4
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some esters maybe but the normal additive system will be the more potent film improver over any base oil.
bruce
bruce
Yes, synthetic oils normally withstand more pressure on the oil film in a boundary lubrication situation.
Not sure if the 7x factor is accurate - it may be an Amsoil number.
The film strength factor is why it's natural to expect the Amsoil oils to perform well in the 4-Ball wear tests, to generate a lesser wear scar, as the "competition" is normally a group of dino/conventional motor oils with less film strength and more reliance on the ZDDP & secondary anti-wear adds.
Not sure if the 7x factor is accurate - it may be an Amsoil number.
The film strength factor is why it's natural to expect the Amsoil oils to perform well in the 4-Ball wear tests, to generate a lesser wear scar, as the "competition" is normally a group of dino/conventional motor oils with less film strength and more reliance on the ZDDP & secondary anti-wear adds.
Well, keeping in mind that on this subject, I'm a self-educated (apart from long ago physics and chemistry classes), I'm with Bruce on this one. He, of course, has cred far beyond what I can offer.
Blue, great comment. From my long ago mathematics, algebra, and calculus classes, I recall integers, fractions, real numbers, imaginary numbers, prime numbers, complex numbers, compound numbers, others I've totally forgotten, but this is the very first time I've hears of Amsoil numbers. What are those??? Should I go back to my undergrad institution and demand some money back for my seemingly inadequate education?
Blue, great comment. From my long ago mathematics, algebra, and calculus classes, I recall integers, fractions, real numbers, imaginary numbers, prime numbers, complex numbers, compound numbers, others I've totally forgotten, but this is the very first time I've hears of Amsoil numbers. What are those??? Should I go back to my undergrad institution and demand some money back for my seemingly inadequate education?
that was me throwing out numbers from memory... remember reading an article somewhere that was comparing dino to synthetic film strenth, saying that most dino oils had a film strength of around 500-900PSI, while synthetics were more like 2000-4000PSI.
I'm glad you started this thread... because I think going over this is important (but probably been done in the past, but things have changed a lot in the last few years)..
there was a time when dinos were dinos, and synths were synths. and now it seems more and more dinos are coming with more and more groupIII, while more and more synths are stepping down to groupIII... So there is probably more overlap in film strength nowadays...
I have heard the following argument:
Any oil has many times the required film strength to keep metal-to-metal contact from occurring in an engine.
But I have also seen pictures of engines taken apart, and seen engines in person all in pieces, and every one of em shows wear on the top of the rod bearings(scarring, marring, etc). (I think it's called a rod bearing, I'm not an engine rebuilder, so I don't always remember all the names of these parts).. but anyways, where the force of the burning fuel, is transmitted down the rod to the crank, there's a lot of force there, and the evidence I have seen, always suggests that oil did NOT keep protect as well as "ideal" would be.
I'd like to see a test, 2 engines on a bench, attached to a load, run like heck for days on end. then torn down... one with dino, one with synth.... full throttle, loaded down to like 3000rpm with some kinda resistance, even a lawn-mower engine could probably be a great platform for this test.
I'm glad you started this thread... because I think going over this is important (but probably been done in the past, but things have changed a lot in the last few years)..
there was a time when dinos were dinos, and synths were synths. and now it seems more and more dinos are coming with more and more groupIII, while more and more synths are stepping down to groupIII... So there is probably more overlap in film strength nowadays...
I have heard the following argument:
Any oil has many times the required film strength to keep metal-to-metal contact from occurring in an engine.
But I have also seen pictures of engines taken apart, and seen engines in person all in pieces, and every one of em shows wear on the top of the rod bearings(scarring, marring, etc). (I think it's called a rod bearing, I'm not an engine rebuilder, so I don't always remember all the names of these parts).. but anyways, where the force of the burning fuel, is transmitted down the rod to the crank, there's a lot of force there, and the evidence I have seen, always suggests that oil did NOT keep protect as well as "ideal" would be.
I'd like to see a test, 2 engines on a bench, attached to a load, run like heck for days on end. then torn down... one with dino, one with synth.... full throttle, loaded down to like 3000rpm with some kinda resistance, even a lawn-mower engine could probably be a great platform for this test.
Film strength is a strange term. What's the test procedure for measuring it? I think the HTHS viscosity means more in an engine and we know the HTHS of many oils so it's a ready data point. And I agree with Bruce, who is my knowledge superior, that additives play a bigger role in laying down films than basestocks apart from viscosity differences.
If you notice the additive levels in synthetic oils are not lower than comparable petro oils I would have to say not exactly ,,,so. Especially pao which is a copy of a perto oil molecule.
Well, ekpolk, a very impressive list of the many matematical varieties of numbers!
I'd say your higher education $ were well spent. But what the academic types at the universities don't teach, or want to admit, is that one of the most commonly used numbers is loosely defined as being "pulled out of a hat"!
And I was thinking about this topic from the additive perspective.
Aren't the additive levels an indication? Both Amsoil & M1 EP are extended drain oils with arguably a minimum of 15K miles built into the formulation.
Since the anti-wear & ZDDP levels deplete over time, should'nt both these formulations have twice the anti-wear adds vs. a conventuinal motor oil?
Aren't the additive levels an indication? Both Amsoil & M1 EP are extended drain oils with arguably a minimum of 15K miles built into the formulation.
Since the anti-wear & ZDDP levels deplete over time, should'nt both these formulations have twice the anti-wear adds vs. a conventuinal motor oil?
I wondered that too, but it could be in the formulation that keeps the additives from depleting as rapidly as those in shorter drain oils. Similar to TBN formulations, some deplete rapidly then level off, others stay high and then diminish quickly.
Here's an older post out of the archives by Molakule:
Yes, raw synthetic base oils have lower coefficient of friction and higher film strengths than do mineral oils:
From Lowest COF to Highest:
1. Esters and cycloaliphatics
2. PAO's
3. GIII
4. GI-II mineral oils.
Now start adding quality additives, and some mineral oils come very close to the performance of full synthetics in terms of COF. Many oils include FM's in order to further reduce COF.
View the entire Thread
Yes, raw synthetic base oils have lower coefficient of friction and higher film strengths than do mineral oils:
From Lowest COF to Highest:
1. Esters and cycloaliphatics
2. PAO's
3. GIII
4. GI-II mineral oils.
Now start adding quality additives, and some mineral oils come very close to the performance of full synthetics in terms of COF. Many oils include FM's in order to further reduce COF.
View the entire Thread
And one more. This is a classic thread from the initial Bitog days, many fine posts by Bob Winters. Well worth it to read the entire 4 pages of the thread!
Film Strength Thread
As posted by Molakule:
From the NEO synthetic oil Website regarding Film Strength and the Test for same:
"NEO has found that most so-called synthetic oils when subjected to the Falex test ASTM D
3233B will fail at about 1000-1350 PSI, and petroleum oils fail at 600- 700 PSI. However, NEO's
High Performance Synthetic 0w-5 motor oil passed the Falex test at 3500 PSI."
Film Strength Thread
As posted by Molakule:
From the NEO synthetic oil Website regarding Film Strength and the Test for same:
"NEO has found that most so-called synthetic oils when subjected to the Falex test ASTM D
3233B will fail at about 1000-1350 PSI, and petroleum oils fail at 600- 700 PSI. However, NEO's
High Performance Synthetic 0w-5 motor oil passed the Falex test at 3500 PSI."
I liked one of the posts in the thread linked by Blue99 so much that I'm going to post it here. The author (cit1991) of it only made 45 posts on BITOG!
I'm totally with bruce.
syth will last longer but not protect better. additives do the work. look at all the uoa's. if syths did all the protection then why do they need additives? I use a blend, not because the oil protects better, the additives do that. uoa's will show that.
That is a very interesting article, but where is the HTHS or esters?
It does show a relationship between syn and mineral. Apparently minerals do quite well at lower temps (<80C), but PAO is better at higher temps. PAG's are not used in automotive lubricants.
The HTHS of oils (old info)with esters
Redline
5w40 4.6
10W40 4.7
15W50 5.8
Motul 300V
5W40 4.51
15W50 5.33
Silkolene PRO S 5w-40 = 4.07cp
Silkolene PRO S 10w-50 = 5.11cp
Silkolene PRO R 15w-50 = 5.23cp
M1
0W40 3.6
15W50 5.11
Redline
5w40 4.6
10W40 4.7
15W50 5.8
Motul 300V
5W40 4.51
15W50 5.33
Silkolene PRO S 5w-40 = 4.07cp
Silkolene PRO S 10w-50 = 5.11cp
Silkolene PRO R 15w-50 = 5.23cp
M1
0W40 3.6
15W50 5.11
I'm not an expert on HTHS (maybe JAG or someone will step in here), but the oils you listed are highly specialized, and are finished oils. Which means that the additives in the oils will affect the test.
Amsoil uses esters as well, and their HTHS scores are about the same as the M1 you mentioned.
Amsoil uses esters as well, and their HTHS scores are about the same as the M1 you mentioned.
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