Darth-Car:
Thanks for all of your info on oil. I had a very experienced Mopar engine builder tell me for a late 60's big block that Valvoline conventional oil was ok but to make sure to use Morey's oil stabilizer with it, or there could be accelerated cam wear. What is your thought ?
When the majority of our cars were designed to have relatively high amounts of phosphorus (in the form of ZDDP) in their oil. Not because I want them to, not because it is an opinion, but because ALL oils that were around when our cars were built (and when the engines were originally designed) had relatively high levels of ZDDP. It was a standard part of the additive package used in all motor oils of the day (conventional or synthetic, Penzoil, Mobile 1, Ansoil, Valvoline, ALL). What has happened is that the API, in response to the reported poisoning of catalytic converters has reduced the amount of ZDDP/phosphorus to the point where the amount of ZDDP/phosphorus is below the minimum amount that the majority of the engines in our cars (meaning all flat tappet engines, not the roller tappet engines) are designed to have in their oils. The key issue is not conventional vs. synthetic, it is whether or not the oil has the adequate level of ZDDP.
See this article from Wikipeida:
https://en.wikipedia.org/wiki/Motor_oil
From that article, in the Standards section,
American Petroleum Institute (API) subsection:
All the current gasoline categories (including the obsolete SH), have placed limitations on the phosphorus content for certain SAE viscosity grades (the xW-20, xW-30) due to the chemical poisoning that phosphorus has on catalytic converters. Phosphorus is a key anti-wear component in motor oil and is usually found in motor oil in the form of
zinc dithiophosphate (ZDDP). Each new API category has placed successively lower phosphorus and zinc limits, and thus has created a controversial issue of obsolescent oils needed for older engines, especially engines with sliding (flat/cleave) tappets. API, and ILSAC, which represents most of the worlds major automobile/engine manufactures, states API SM/ILSAC GF-4 is fully backwards compatible, and it is noted that one of the engine tests required for API SM, the Sequence IVA, is a sliding tappet design to test specifically for cam wear protection. Not everyone is in agreement with backwards compatibility, and in addition, there are special situations, such as "performance" engines or fully race built engines, where the engine protection requirements are above and beyond API/ILSAC requirements. Because of this, there are specialty oils out in the market place with higher than API allowed phosphorus levels. Most engines built before 1985 have the flat/cleave bearing style systems of construction, which is sensitive to reducing zinc and phosphorus. Example; in API SG rated oils, this was at the 1200-1300 ppm level for zinc and phosphorus, where the current SM is under 600 ppm. This reduction in anti-wear chemicals in oil has caused premature failures of camshafts and other high pressure bearings in many older automobiles and has been blamed for pre-mature failure of the oil pump drive/cam position sensor gear that is meshed with camshaft gear in some modern engines.
There are three
diesel engine service designations which are current: CJ-4, CI-4, and CH-4. Some manufacturers continue to use obsolete designations such as CC for small or stationary diesel engines. In addition, API created a separated CI-4 PLUS designation in conjunction with CJ-4 and CI-4 for oils that meet certain extra requirements, and this marking is located in the lower portion of the API Service Symbol "Donut"."
There are a lot of good oils out there, including Amsoil. The question is not the quality of the oil, but whether the oil that meets current API specifications also has adequate levels of ZDDP for our older cars. If an oil is made to meet the current API specification (SN), IT CANNOT HAVE ADEQUATE LEVELS OF ZDDP FOR FLAT LIFTER ENGINES. THe API SN specification DOES NOT ALLOW IT. This is why the need tor conventional oils, and specifically Lucas Oil's "HOT ROD OIL", or Rotella T conventional oil. If you can convince AMSOIL to create a synthetic oil with high levels of ZDDP (which by extension, means that it cannot be used for modern cars, due to its poisoning of the catalytic converters, and not meeting new car warranty requirements), then I would be willing to try it. However, until such time as this comes about, Rotella T conventional is it.
Also, before you come on here with a sales pitch, I suggest you read the HOT ROD article that I previously linked to.
And just for the record, I use AMSOIL in my daily driver (a 2006 Monte Carlo SS). I use WIX filters. I use the synthetic oil because that is what the owner's manual calls for. Guess what? The owner's manual for my 3 J Bodies calls for oil that meets SE/SF standards. Those standards had high levels of ZDDP. The current SN grade does not. I choose to think that in both cases, the engineers who designed those engines knew that they were talking about. I have full confidence in that.
