Follower scar oil tests (2018)

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Mobil 1 rep answers the question of "Why does Royal Purple outdo Mobil 1 in scar testing"



https://mobiloil.com/en/faq/ask-our...trength-of-mobil-1-compared-with-royal-purple
Interesting response that it’s due to the other oils having additives for ‘extreme pressure’...
Which he says is more for gearboxes than engines.

I wonder if this is another case of miss understanding of the different needs of old engines?

I would have thought that the cam and follower interface on our engines, with no rollers etc, definitely constituted ‘extreme pressure’!

So perhaps modern engines, with better pumps, tighter tolerances, liquid cooling, and bearings everywhere just don’t need the same kind of protection as our old obsolete lumps...
 
I'd gladly donate to the cause. However, money won't buy Jim a clone and I hate to wear out a resource by endless requests to test variations. I fully believe in supporting the work that keeps these bikes on the road.

I suspect that what I will end up doing is ordering in some Royal Purple and conducting a few tests of my own. They won't have to match Jim's if I use the Royal Purple as a base line. Either stuff will pass or fail based upon that comparison. That still doesn't give a straight line. Suppose the entire line of Royal Purple oils get a pass. You still have to decide whether to run HPS or XPR (or another).

I've read so much stuff that my head is about to explode. I think I need to change the oil and go for a ride.
 
Perhaps scar testing combined with oil analysis would give us a good idea of which oils are best for these engines.

Glen
 
Jim, what "cam" rpm are you running? It's obviously higher than ~500/idle rpm. I'd be curious if you could run, say, the best and then the worst of your prior tests at a low rpm, thus possibly removing the hydroplaning affect. Thoughts? And, thanks so much for all you've done here!

Nathan
 
Jim, what "cam" rpm are you running? It's obviously higher than ~500/idle rpm. I'd be curious if you could run, say, the best and then the worst of your prior tests at a low rpm, thus possibly removing the hydroplaning affect. Thoughts? And, thanks so much for all you've done here!

Nathan

The arbor speed is 3425 rpm.
 
Anyone using this: Mobil 1 V-Twin 20-50. P: 1600, Zn: 1750? It's states V-Twin motorcycles where 20-50 is specified. And for just street riding, what's the preference: Dino or Syn? Everything thing seems fine in my 71 as I've owned it since 74 and have always used Castrol GTX 20-50 but after reading all these oil threads it seems it's not like the original back in the day!
 
Interesting response that it’s due to the other oils having additives for ‘extreme pressure’...
Which he says is more for gearboxes than engines.

I wonder if this is another case of miss understanding of the different needs of old engines?

I would have thought that the cam and follower interface on our engines, with no rollers etc, definitely constituted ‘extreme pressure’!

So perhaps modern engines, with better pumps, tighter tolerances, liquid cooling, and bearings everywhere just don’t need the same kind of protection as our old obsolete lumps...


Speculation on my part but it could be an oil suppliers attempt at a formulation intended to address engines which share engine oil with the gear box. Ducati's and others come to mind.
 
Oil suited for combined engine and gearbox use has a JASO MA
designation.
Apparently an oil that is free from friction modifiers is needed as the friction modifiers cause the oil clutch to slip.

Shell Rotella Diesel Synthetic T6 has that designation.
A lot of Modern bike owners use the T6 as an alternative to more expensive Motorcycle oils with the same designation.
I was thinking of sending some to Jim for testing, except it is 5-40 weight, maybe not suitable for the Norton.
Shell notes that it replaces their old 15-40 diesel oil.

Glen
 
Anyone using this: Mobil 1 V-Twin 20-50. P: 1600, Zn: 1750? It's states V-Twin motorcycles where 20-50 is specified. And for just street riding, what's the preference: Dino or Syn? Everything thing seems fine in my 71 as I've owned it since 74 and have always used Castrol GTX 20-50 but after reading all these oil threads it seems it's not like the original back in the day!

I used Mobile 1 v-twin oil for years before I recently switched to Royal Purple.
Mobil 1 v-twin works very well.
Comparing those two was what started all this. Jim

PS, Do not use XPR in a bike with a clutch that runs in the engine oil.
 
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Oil suited for combined engine and gearbox use has a JASO MA
designation.
Apparently an oil that is free from friction modifiers is needed as the friction modifiers cause the oil clutch to slip.

Shell Rotella Diesel Synthetic T6 has that designation.
A lot of Modern bike owners use the T6 as an alternative to more expensive Motorcycle oils with the same designation.
I was thinking of sending some to Jim for testing, except it is 5-40 weight, maybe not suitable for the Norton.
Shell notes that it replaces their old 15-40 diesel oil.

Glen

I have used it in the winter. I think I still have some to test. Jim
 
Oil suited for combined engine and gearbox use has a JASO MA
designation.
Apparently an oil that is free from friction modifiers is needed as the friction modifiers cause the oil clutch to slip.

Shell Rotella Diesel Synthetic T6 has that designation.
A lot of Modern bike owners use the T6 as an alternative to more expensive Motorcycle oils with the same designation.
I was thinking of sending some to Jim for testing, except it is 5-40 weight, maybe not suitable for the Norton.
Shell notes that it replaces their old 15-40 diesel oil.

Glen
Not positive on this one, but believe all the Amsoil motorcycle oils are formulated for use with wet clutches.

https://www.amsoil.com/newsstand/motorcycles/articles/how-a-motorcycle-wet-clutch-works/
 
According to Royal Purples tech line they achieve their film strength by ionic bonding.

https://www.rdmag.com/award-winners/2014/08/low-friction-engine-oil
Don’t know if the link provided in Comnoz’comment above refers to the specific ionically bonded anti-wear technology employed by Royal Purple – maybe, maybe not? Even if the article does not refer to the specific Royal Purple technology, it is nevertheless interesting technology that employs ionic liquid oil additives that provide a synergistic effect with oils containing ZDDP. Since the forum readership is now expert in their knowledge of ZDDP chemistry (don’t be bashful you are all experts now aren’t you?), thought you may want to move your understanding of this “ionic liquids” technology beyond the words and see what is actually going on in the oil to provide the enhanced anti-wear performance.

The articles I’ve found on the subject are only abstracts, as permission or membership is required to read the full articles, yet reveal what occurs that provides the synergistic anti-wear effect. The image below is from an abstract by the Oak Ridge National Laboratory group that shows the chemistry involved. I apologize for the quality of the image but it is what it is.

https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201502037

Follower scar oil tests (2018)


To understand the image let’s begin by identifying the chemicals present. On the upper left of the image you’ll recognize your old friend ZDDP (the Zn dithio blah, blah, blah, oriented vertically in this case) with a dashed orange box around the lower half of the ZDDP molecule. Then just to the right of ZDDP (past the “plus” sign) are the ionic liquids, consisting of a phosphonium cation shown on top and having a positive charge (has the 4 R groups oriented about the P atom), and below it encircled with a solid green line is the anion having a negative charge. Moving further right past the reaction arrow are the new products formed. The molecule shown in solid green is the one to keep your eye on as this is the new molecule with synergistic anti-wear properties. Examining the structure of the new molecule you’ll note that the top half of the molecule is unchanged ZDDP, but the bottom of the ZDDP molecule has been replaced by the ionic liquid anion.

I believe (but don’t know) that the legend/key to the performance graphs is as follows. ZDDP is shown in blue, and the phosphonium ionic liquids are shown in orange, where both additives, employed as the sole additive, provide reasonable anti-wear performance on their own. However, the novel performance lies in the synergy that occurs when the orange and blue are combined to provide the new green molecule.

The last link below names a specific phosphonium ionic liquid that when combined in a fully formulated motor oil provides the above described synergy in anti-wear performance. Some of the same authors as above, but earlier publication date.

https://pubs.acs.org/doi/full/10.1021/am201646k

As mentioned previously, the formulated cost/performance ratio of any oil we buy is unknown, but I wouldn’t be the least bit surprised if additives like those described above might add significantly to the raw material cost of a motor oil, hence in some cases the price may relate to performance and "what's in the bottle".
 
Paying a premium price for a quality product is much preferred to paying premium and getting garbage. The latter is all too common.
 
Oil suited for combined engine and gearbox use has a JASO MA
designation.
Apparently an oil that is free from friction modifiers is needed as the friction modifiers cause the oil clutch to slip.

I am thinking engine oils designed to accommodate gear boxes likely have "Extreme Pressure" additives; maybe something other than (or in addition to) the more commonly known Zinc and Phosphorus additives.
The link provided earlier below shows an example JASO MA rated oil - see Mobil 1 Racing™ 4T "where clutch lubrication is important"
https://mobiloil.com/~/media/amer/us/pvl/files/pdfs/mobil-1-oil-product-specs-guide.pdf
The Zinc and Phosphorus content of that oil seems to be on the highside of the middle of the pack for the oils listed so maybe there is more to a dual duty engine oil or maybe the OEM recommends an oil recognizing there will be trade offs. I am wondering if there's more to it for dual purpose engine/gearbox oils. Friction modifiers are a whole different kettle of fish and that is where I think some clutch applications have had problems.
 
My very limited, and uneducated, understanding of zinc in oil is thus:

In an engine where the oil is functioning ‘correctly’ and within its performance perimeters, zinc doesn’t really do much.

Zinc comes into play when the oil film has broken down, its the last defence before metal to metal contact.

In our flat tappet engines, the cam to follower interface is such a case, where in some circumstances, that metal to metal contact may occur, and therefore, that’s why the zinc is so important. And also therefore, that’s why more modern engines just don’t need it.

How right / wrong is the above??
 
My very limited, and uneducated, understanding of zinc in oil is thus:

In an engine where the oil is functioning ‘correctly’ and within its performance perimeters, zinc doesn’t really do much.

Zinc comes into play when the oil film has broken down, its the last defence before metal to metal contact.

In our flat tappet engines, the cam to follower interface is such a case, where in some circumstances, that metal to metal contact may occur, and therefore, that’s why the zinc is so important. And also therefore, that’s why more modern engines just don’t need it.

How right / wrong is the above??
Fast Ed, you are undoubtedly one of our foremost ZDDP whisperers as your grasp of their function is very close to (my) reality. Phosphorous and sulphur content of oils has been regulated way back because it poisons the Pt in catalytic converters rendering them non-functional in the general fleet of passenger vehicles. Oils can still contain these additives but just not as much as they once did.

When you say ….. “where oil is functioning “correctly” and within its performance parameters, zinc doesn’t really do much”, this statement may require some slight qualification, i.e., ZDDP would still be performing it’s duty anywhere there is temperature/pressure that causes it to activate and deposit a Zn polyphosphate anti-wear layer (cam/bucket/follower operation). Your statement of course has merit because, in general, modern engines have superior surface finishes (minimizes possibility for metal to metal contact to occur), overhead cams, and 4 valve heads having small light weight valves/valve train, that require only modest valve spring pressure (you can literally depress with hand pressure), so consequently the sliding loads are light relative to our dinosaurs, and yes, in such applications high levels of ZDDP are likely not required for the majority of modern low performance passenger vehicles.

My 2005 Toyota Sienna is testament to the above with 355,000 mi, run on Walmart brand shit-grade oil (~$12-13 USD/5 qt) for the last 250,000 of those miles, never had a valve adjustment and still has the original spark plugs in it.
 
Apparently an oil that is free from friction modifiers is needed as the friction modifiers cause the oil clutch to slip.

Glen

One has to wonder, if friction modifiers are so good, surely oil without them has to be less good than oils with them ?!
 
One has to wonder, if friction modifiers are so good, surely oil without them has to be less good than oils with them ?!

I don't think the case has been made for friction modifiers causing the clutch to slip; well at least the Phosphorus and Zinc additives. Oil, not unlike an IC motor, seems to be a compromise, where the needs to address various lubrication regimes. With the friction modifiers, they are apparently there to primarily address the boundary lubrication regime. As engine designs change, so do the specific (or ideal) lubrication requirements.
 
With a modern setup the oil has to work with clutch ( not too slippery please) , gears( extreme pressure) bearings, bushings, rings, valve train ( slippery is generally good) and not take out the cat.

How do they do it?
And yet these Moderns seem to run forever with long stretches between oil changes and very little other maintenance.

I don't think that is all down to Wonder oil.
The incredible reliability and longevity of Modern engines probably has more to do with improved metallurgy and design combining with some improvement in lubrication.

Glen
 
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