Follower scar oil tests

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One thing worth considering re ZDDP - any oil that has sufficient zinc/phosphate to satisfy the gear-head Flat Tappet/OHV scenario would not be suitable for a Cat converter and, therefore, should specifically state something to that effect.

Several oils of which I am aware with that level of zinc state on the bottle, "Not recommended for passenger car use" or similar words. If an oil claims it is suitable for racing and for street use...well, maybe the race cars they are referring to have cats! :)
 
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I would like to see the Redline 20-50 tested also, I am running that in my bike and it seems to be perfect....I do not see the point in adding more zinc to the VR1 as that is not what you are buying off the shelf, I used to run that but it used a lot more oil when I did....great test Jim....thanks. I have also used Joe Gibbs, that seems really good also , would like to see that tested!
No, but adding the zinc to that oil will show if it's more zinc alone that improves the results.
 

oldbeezer

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Jim, thanks for showing us this. No doubt you are very busy with all of this but if you find time I have a request. I realize this is not germane to our Nortons but I would like to know how castor bean oil would do in your test. It also smells great.
 

comnoz

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I do want to test some Redline 20-50. I will have to order some in.

I also have some Royal Purple Max Cycle 20-50 that is listed as containing 3200 ppm zinc. It is about half the price of the XPR 20-50 and I have been using it in my FJ.
I will be testing it soon.

That and the bean oil sounds interesting.
 
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comnoz

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One other thing concerning zinc -as I understand it -and I am by no means an expert in oil chemistry.

There are two types.

One type combines with phosphorous to make up ZDDP or ZDTP. This mainly provides start up protection by attaching to hot engine parts.

The other type acts as an extreme pressure additive.
 

cliffa

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Jim, thanks for going to all the trouble of posting this, it's really very interesting. One thing i'm surprised about though - why no WD-40 test ? ;)
 

Brooking 850

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Thanks Jim, excellent testing .
PM if you require the cost of the Joe Gibbs.Heres hoping it performs well.
Regards Mike
 

Fast Eddie

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Jim, I’m sure you know this already, but please ensure you test the motorcyclemoil from redline rather than their automotive oil.

Personally, I run their 20/60 motorcycle oil, but I have been considering their competition oil lately...
 

comnoz

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1st test

I went ahead and tested the Royal Purple XPR 20-50 at high temperature. No problem.
Then I added another 80 lbs of pressure. Problem.

2nd test
Royal Purple Max Cycle 20-50. One of the highest zinc concentrations I have seen at
3200 ppm. The zinc did not replace the low friction additive that is in the XPR.

 

WZ507

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https://www.activ8lubricants.com/

Those tests remind me of the ones I have seen at shows where the use of this additive looks far, far too good to be true...I don't suppose you get this in the US but I could send some as I would be interested to see if lived up to the promises.
We do see such tests in the US. I recall decades ago seeing some magic product on a rig of the same genre as Comnoz', where perhaps a Lucas friction modifier was employed and it certainly looked like a wonder drug in the specific test protocol being used.
 

WZ507

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One other thing concerning zinc -as I understand it -and I am by no means an expert in oil chemistry.

There are two types.

One type combines with phosphorous to make up ZDDP or ZDTP. This mainly provides start up protection by attaching to hot engine parts.

The other type acts as an extreme pressure additive.
We’ve likely all read more about ZDDP than we care to know, yet understanding the basic chemistry may not be obvious to all so will attempt here to provide a simplified overview of this class of molecules and how they work. To amplify a bit on Comnoz comments above, I too am no expert on motor oil or ZDDP (zinc dithiodialkylphosphate), but do have a working grasp of the chemistry which may help us better understand some of the results we see.

To begin, the class of molecules known as ZDDP function as antioxidants, corrosion inhibitors and anti-wear agents. As stated by others, ZDDP is not a molecule, but rather a class of molecules. All ZDDP molecules share the common structure shown below (enclosed in red brackets), where S is sulfur and refers to the dithio part of the name, P is phosphorus which is associated with the phosphate part of the name and R and R’ are hydrocarbon groups or the dialkyl part of the name. These alkyl groups are the components that distinguish one ZDDP molecule from another.

ZDDP.jpg


The R and R’ groups or so-called substituents are hydrocarbons and can be long or short, straight chain, branched chain or cyclic structures, and can be attached to the parent ZDDP group by their ends or somewhere along the chain. All these variants in substituents give rise to the myriad ZDDP molecules available to the oil formulators. Note that Zn and P occur in a ratio of 1/2, and considering their molecular weight, should always occur at a weight ratio of ~ 1.0/0.95. Thus when you are reading oil specifications, if the zinc content is 1000 ppm the P content should be 950 ppm if both atoms are from ZDDP. If this is not the case, there is additional P in some other form and for some other reason (antioxidant, corrosion inhibition, etc).

So, why would we care about all these possible variants of ZDDP? Because the R/R’ substituent relates to the stability of the molecule, and the molecule has to degrade to function as an anti-wear agent. More specifically, ZDDP functions by breaking down (thermally or mechanically), losing the hydrocarbon substituents, and forming a zinc polyphosphate glass on metal surfaces. It is this zinc polyphosphate layer that provides boundary lubrication, i.e., lubrication in the absence of a coherent oil film, via the hard, durable, low coefficient of friction layer formed.

By selecting a specific ZDDP molecule or variety of molecules an oil formulator can tailor the lubricant to provide the desired performance. For example, if a formulator were designing a break-in oil, they would select a ZDDP molecule that had limited stability so that upon initial engine start-up ZDDP would degrade quickly to provide the zinc polyphosphate layer ASAP after firing. Such a formulation would likely also contain some ZDDP of intermediate and longer term stability to provide a continuum of protection. I suspect for a high mileage motor oil where immediate protection is not the primary need, the ZDDP selected would be a very stable molecule that would degrade slowly to provide protection over a long period of time.

The foregoing should be a reminder that although some given oil has a desirable level of ZDDP in it, we have no idea which one of the dozens of ZDDP molecules or range of molecules it contains and perhaps not be surprised that all oils with the same ZDDP level are not created equally and don’t perform equally. Furthermore, some other additive, e.g., a moly friction modifier may provide some synergistic effect with a specific ZDDP, so very possible that ZDDP is not the whole story.

There is also the possibility that a particularly desirable ZDDP molecule might have a steep cost/benefit ratio relative to other molecules, hence the formulator has to balance the formulation cost vs performance vs the marketer’s desired selling price.

The link below to a Joe Gibbs oil primer hopefully reinforces the key points made above.

https://www.drivenracingoil.com/docs/dro/RacingOil101.pdf

Here’s what Amsoil has to say about ZDDP and their recommendation of their two Z-ROD oil products for flat tappet cams.

https://www.amsoil.com/newsstand/classic-and-vintage/articles/reduced-zddp-and-wear-protection/

Possibly one of these Amsoil offerings may make it into Comnoz test cycle. However, I can also see that this could be an open ended test protocol by the time we are all satisfied with all the oils evaluated. How about GM’s EOS as an additive?
 
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lcrken

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Thanks for the explanation, Kurt. Well written and very informative.

Ken
 
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Nice explanation! This is a good reason that it makes sense NOT to buy ZDDP additives and dump it into oil. You don't really know WHAT it is and you don't know how the stuff will react with the additive package already in the oil. It could imbalance the package so that the oil provides less protection than it did originally. :(
 
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It's been BIG DEAL for many years in just about every old/vintage OHV engined-car and moto forum. Of course, for Motos that pretty much just means, with a few exceptions, old brittbikes and Harleys! In the rest of the vehicle world, it is like worrying about who makes the best buggy whips! :)
 
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