He is way off base. He starts off with his idea of a scientific experiment, but there is one huge fallacy. I would compare it to taking samples of Milk from the grocery store and scientifically searching for alcohol. He does not look for all anti-wear additives, only ZDDP. It is hard to find what you are not looking for.
ZDDP is used in automotive engines because it is effective and relatively cheap. There are variations in price due to it's evaporative properties (hence SN with the more expensive types). Aircraft engine oils, TC-W3 two cycle oils, and two cycle stationary engine oils cannot have residual ash after burning in the engine. In the case of the aircraft, you don't want fowled plugs at 10,000 ft. You can't pull over and clean them. In TC-W3, you don't want fowled plugs in the middle of the bay, or, in my case a few years ago, fighting the heavy currents of the Amazon to get back up river to your camp after dark with millions of mosquitos and thousands of bats flying at you -- it was not fun. The owner of the plane used the right oil for the plane, but not for the boat. In the case of large two cycle stationary engines, the ash builds up on the ports in the sides of the cylinders, reducing the exhaust flow. Pulling a huge engine off line to clear the ports means loss of production and a huge expense.
Each of these engines have different power and RPM requirements, but as mentioned on the forum, in the case of the Lycoming and other aircraft engines, they are low and steady RPM, without the need for high valve spring pressures (ash is used to cushion the valve seats against the spring pressures) and therefore have less pressure against the rocker arms and tappets. It has been mentioned that cams can go 2000 hours on these engines. In comparison with car engines, that is a drop in the bucket.
So a more expensive anti-wear package is used that is non-organometalic. It leaves no trace ash to be analyzed.
Before we look at his results from the Aeroshell, we should note that he was running a SM oil. Running an SM oil, known for it's lack of sludge prevention for 18 months is asking for a build up (or accumulation) of byproducts that will take a while to clean up unless you use AutoRx or something similar. As with any change in formulation, I would not be surprised by the same or higher contamination and wear metals, as it's different detergent or solvency may be dislodging old sludge (this is particularly important in the silicon result, where unless he "cleaned" his filter or put on a new one, there is no other normal explanation for the increase in silicon). I will also mention that his entire history of silicon in this engine indicates a problem with his air intake. Any decent filter in a correctly assembled and sealed air intake can easily keep silicon below 5 ppm except maybe in the first 5000 miles as it fills up and starts to clog the bigger holes). 4 to 24 ppm of silicon in 1500 to 2000 miles is way out of line.
I'll also comment on certain levels that are slightly off-topic, but bear commenting on since I've analyzed about 5000 samples in the last 10-12 years and use them for pro-active maintenance. I do not look at averages. Each engine, transmission, or whatever should be compared to it's counterpart if possible and benchmarked to the best known practices. Unless an engine oil is formulated with silicon anti-foam (some of the SN formulations), I do not let my customers get over 10 ppm in silicon. It can be avoided with good filtration. Their 31 ppm of iron as "averages" is scary. With good oil and filters, as well as certain other good practices, We can keep iron below 3 ppm per 5000 mile oil change in car, SUV and pickups. Any agricultural or construction equipment that can't do 500 hours with less than 25 ppm of iron is not being taken care of with the proper oil, filters, washes, etc. We immediately audit the maintenance and operational procedures of the customer to identify and correct the cause, whether it is mechanical or human. With these practices we see most CAT, Komatsu, and Agricultural engines passing the 25,000 hour mark without rebuilds, and the cams last at least 50,000 hours. (compare to 2000 on a Lycoming). So I have never agreed with the Blackstone averages. It is easy to be average. I took one company with 40 identical pickups and brought their "normal" iron wear from 12 ppm per 1000 km to 2 ppm per 1000 km. In my identical pickup I run 1to 2 ppm of iron per 6000 km, but then I've run the same good practices since day one (10 years and 350,000 km ago). Bottom line is I never look at Blackstone averages.
We do not know what kind of driving he does with his 100 miles a month. If it is short trips or "warmups", that will account for much of the iron. His high lead is probably corrosion of the lead from dirty oil sitting in the bearings for long periods of time, especially if he starts it occasionally to keep the battery charged or whatever. I've already proven that it is better to just let it sit. My 1988 BMW and 1960 Corvair only get 2000 to 4000 miles a year on them because I'm not always where I keep them. When I start them, I drive them 60 miles a day to work (15 miles of mountains each way, 4 times a day). If I'm not going to town, I don't start them. And I use synthetic CI-4 oil, changing once a year, no matter what, and timed to be dress before one of the periods I'll be away.
Now if we look at his analysis, we see that he was previously using a high moly content oil. As he says, about 20% of the previous oil stays and contaminates the new oil, so it is natural to see the 260 ppm of moly reduced to 59, and then to 21. The same with the other additives as they either remain on the engine to be worn off or say in the residual oil. Remembering that zinc, phosphorous, calcium, boron, and moly are polar, we can see that even in his second Aeroshell sample he still has some ZDDP and other normal additives in that oil. The Aeroshell would have zero of those elements.
So what do we see in those results? A continuing reduction of the polar additives that are still offering some protection in addition to the non-ash additives. My guess would be that if he continues the test, his wear metals will go up as the old polar additives continue to wear off.
So, bottom line on ZDDP:
I've written my main paper on the subject. I still believe it is necessary in flat tappet engines. I also believe some people take it to extremes. The levels in any oil on the market are higher than they war 50 years ago. One of the readers of my paper has offered a quart of oil from the 60's for analysis, so as soon as I see those results I'll have an idea of what was in the market (other than the theoretical that I've used to date).
I DO NOT believe in "mix-your-own" with ZDDP supplements. The damage of going over 1600 ppm is not good. The damage of going over 1800 ppm is documented by SAE studies. Why risk it when a good CI-4 is plenty and will keep the engine clean as well? Even a Synthetic CJ-4 is great. And go with the Synthetic and you are probably (I don't have the test equipment) a level of elastohydrodynamic lubrication to the mix.
Thanks for bringing this up. Although a lot of what he says has been debunked on the forum, I'll go ahead and post this there as well.
Link to the seleccion of engine oil for flat tappet engines
