Hi Robert,
I've read quite a few of the posts and comments you have made in the forum section, and have a great respect for your knowledge which you have shown on the various topics. I'm flattered that you have given me the chance to express my opinions about the subject of "synthetic vs mineral" engine oil.
First off, in aircraft (piston type engines) use, all engine oils which contain zinc in any level are taboo.....the reason being that it effects the silver wrist pins in those engines, and you sure don't want to have a seized piston while up in the air. The aircraft engine oil business has been pretty much sewed up by shell with their "aero-shell" product line. To even think about bringing in an oil for piston aircraft engines would be astronomically staggering price wise, as the oil would have to be approved by engine for each engine out there, of which there are literally thousands, and the cost involved with the various testing procedures and of course the faa could easily run into the tens if not hundreds of millions of dollars. So, as for shell, (and maybe one or two others minor players) they have been around for a long time, in on the ground floor so to speak, so each new engine test is not an unsurmountable task.
I take it that you are into drag racing, and you probably well know that both synthetic, synthetic blend and petro-stock oils are used. The choice of the race team, or owner to the type of oil they use is probably either a recommendation of the engine builder, or even through brand loyalty. The reason why oxidation and varnish is not as apparent those engines is because of the fact that the oil is changed very frequently, especially depending on the class of car involved....as you know some of those high-dollar teams might only use an engine once, then change the engine..... Then completely tear down and rebuild the engine again!
Now, to get into the meat of your question..... You know there are several different types of "synthetic oils" on the market today. The most common that you will see as far as the "national brand" oils are actually either polyalphaolefins (pao), which are mostly blended with petro-stocks to produce a "semi-synthetic" or "synthetic blend" oil..... The trouble is the manufacturer does not need to say how much synthetic oil is in the blend...... Or oils made from group v base stocks, which is a process that has been developed in which petro-stocks are "re-worked" to have "synthetic-like characteristics." it is estimated that these oils are about $1.00 per gallon less to produce than the pao oils are, and they have pretty much taken over a large segment of the shares of the market. Did castrol, or the others lower the price of their oils when they went to this type of processing? - certainly not! They are allowed to call this oil a "synthetic" oil from a ruling by the ftc because of the fact that it has "synthetic-like properties." these engine oils are in a different category than what we in the industry call "true synthetic" oils such as red line and one or two versions of royal purple.....most other oils which call themselves "full synthetic" are using a legal loophole. (incidently, red line only makes synthetic oils, whereas royal purple makes both synthetic oil as well as "semi-synthetic" with a pao/petro-stock combination.) from what I understand, mobil 1 as well as amsoil are pao enhanced oils. Mobil at the present time is suffering from a pao shortage because of when hurricane ike went completely through their production facility in houston last year.
The reason I am relating all of the above is the fact that there are many different varieties and qualities of synthetic oils on the market, but the average consumer does not have any idea of how the whole marketing strategy has clouded the issue. There have been countless times when I have been talking up swepco's engine oils, and what we have been able to see them achieve, then the prospect will say: "sounds like a synthetic oil to me" and nothing could be further from the truth.
The biggest advantage of the pao and the newer so-called synthetic oil is the fact that they do have a lower pour point, and are really the best oils to use in arctic conditions. Some have a higher flash point to which you are alluding, the highest being the true synthetics such as red line produces. They do not use the same type of viscosity improvers due to the fact that the chemistry doesn't readily accept them. So, you are correct about what you call viscosity stabilizers, but only in certain oils.
For the most part, it has been acknowledged that mineral oils will handle 98% of the engine oil requirements for automotive (I lump in high performance in automotive), trucking and construction type equipment. The remaining 2% of the market has been overstated up to around 20 to 30% of consumer choice because of the marketing blitz favoring synthetic oils. It has even gone so far as that oem's have recommended synthetic oils for their cars to keep their warranty valid (which is not really necessary), for example, bmw for years has held the position that owners use their bmw 5w30 synthetic oil and change their oil every 15,000 miles to meet warranty requirements. They even come with free oil changes when you buy a new car and the dealership will not change the oil unless it has 15,000 miles on it..... Just ask an independent bmw shop what he thinks of that program after seeing all of the varnish and sludge in those engines!
Synthetic oils also need to have a robust additive package, but the problem with the paos is the fact that it does not hold the additives in suspension and they "drop out" and just lie there in the bottom of the oil pan. That is another reason why you do not see a lot of zinc in synthetic oils and the problem is that it is relying on the film strength of the oil to perform the necessary lubrication in the engines.
Yes turbo temperatures and ring temperatures can be a real killer on oil, but depending on the quality of the oil you choose, they are not necessarily deadly.
Swepco branded engine oils are not synthetic (can you tell by my diatribe?), they have been producing engine oil for over 75 years now and certainly have the ability to come up with a synthetic product. However, due to the fact that it would not be as good a product as our petro-stock engine oils are, they cannot see a reason to just be "another company who has a synthetic engine oil."
you sound as though you are pretty satisfied with the synthetic oil you have been using, and that is called "product loyalty," I've got a lot of customers who have switched and they are now loyal to swepco! My advice to you is that if you are totally happy with what you have and it has served you well, then stick with what you are doing, but if there is any kind of wonder in your mind that "maybe there is something better out there," then give us a try!
If your diesel pickup is pre 2007, make sure you use ci-4 rated oil in it as the new cj-4 has a much lower additive package. We make both the ci-4 as well as the cj-4 for newer engines and I've got customers who as an average change their oil every 15,000 miles....including those with light towing conditions. Price wise, we are going to be close with the "true synthetic" engine oils, quality wise, we are tops!
You asked, and that's my take on it.....I'm sure to draw some criticism, but that's the way it is! Some people really like synthetic oils and "swear by it" - I prefer to say that I "swear at it!"
keep up the good work,
dick
just a puff. I was reading Jesse post on the valve guides, but looks like he had machine work done to fit some other parts. I don't want to pull the heads on a new motor. Was just hoping to find something that could be done with just the valve covers removed. I suspect the oil sitting in the valve cover near the rear and when a valve is open, allows oil to drain into the camber might be the cause?