In a huge FWIW moment...
QUOTE: "That they would have to reforumlate the oil, detracting from it's protection, to meet the API spec. . ." That sounds like marketing/ sales hot air to me. What ever happened to 'meets or exceeds' ?
****Okay, here goes: It could sound like a lot of things.....IF it meets a spec THEN it COULD exceed it. Basically the message as explained to me: If it does NOT meet the spec, because of a certain additive(s) required to qualify for an API classification, does not mean an oil cannot or does not still protect the engine, perhaps even better than the API spec itself calls for.......Get it? Other than that, I can't say with any certainty one way or the other.....this info wasn't from Amsoil, however (Redline).....think it comes down to the vast differences in fossil vs syn oil, all the various standards that are needed for fossil oil, that don't seem to quite so apply to syn oil, such as the way viscosity and flow characteristics are to vastly different at extreme temperatures, and how fossil oil heavily relies on additives to perform. I am no scientist, but do grasp what was explained to me, and knowing how big business works am not surprised there is more than one layer to dig thru to find real information. No doubt we'll all be chasing valid and true data until finally giving up in our final days.

this is probably true. In order to meet the new CJ-4 spec most oils had to have levels of detergent and friction modifiers like ZDDP reduced to meet the sulphated ash content requirement of 1.0 In most engines, high detergent and additive package level were something to boast about. They contribute mightily to Amsoil's ability to recommend extended drain intervals.
**** That's a BIG assumption that relies on propaganda from 20+ years ago: that Amsoil uses high levels of "high detergent and additive package level" and that "contribute mightily to Amsoil's ability to recommend extended drain intervals." That is a big statement to make, can you support this in ANY way? From what I understand Amsoil uses very low levels of any additives especially VI (Viscosity Index) improvers. Their base oil is good enough (type 4 and 5) that high concentrations of additives are not needed, and detract from it's performance. Often what makes oil break down is the additives themselves. Why not "nip it in the bud" and just use better base-stocks? Well, it COSTS more and most people don't understand why and therefore buy the cheapest products. The sad thing is that it the long run it'll just cost more....
Part of what I read is that oil manufacturers of CJ-4 who used to recommend extended intervals with earlier formulations now recommend sticking to the engine manufacturers drain intervals, until a testing routine can be established.
**** If that is the case, it appears Amsoil is an exception. There are some engines that are prone to problems, and occasionally drain intervals are adjusted. Amsoil has a list on line, but did not see anything for diesel engines, just gas. Correct me if wrong.
I'm going to stick to CF-2 as long as I can find it in my DD.
**** Good call in my book, me two: Amsoil 15-40 CF-2 Diesel Oil. All 11 gallons, plus another 5 gal pail of gear oil for the diff and manual trans that will go in this spring (will probably need 8+ G but will start with the trans).
But - I run flat tappet race engines for myself and for customers, and have been recommending diesel oils for break in due to the higher levels of ZDDP, hence my fascination with oil formulations. We all missed when the car oils were reformulated to reduce additives, ZDDP dropped to about half of what we needed. We lost a brand new cam in a brand new $15K race engine, and no one was happy, and I got very paranoid...
**** Might be worth considering what base stocks are used in the oil, more so than an additive, which in essence just helps support engine parts when the oil can't

I've had oil problems too over the last 20yrs, including with the best know brands of fossil oil available-- such as TOTAL viscosity breakdown in just 1800 miles in a low mileage bone stock daily driver car; ZERO PSI on the oil pressure gauge; an oil change solved that. The high zinc content seemed to have protected the bearings just fine (engine was not taken apart, but oil pressure was still good), even though it was driven over 300 miles with no oil pressure. That episode converted me to a believer of synthetic oil, not to mention everyone I knew that raced at Sears Point (now Infineon) raceway used synthetics, most of them Redline products, another brand I highly respect, trust, and have used for 20 years.
Best of luck, but please, myself included, let's stick with current and valid information, to avoid the throw net sized asumptions that are often wrong and confuse people even more. If we guess then let's make it known, if told by someone else, then mention it.
Thanks for listening (everyone), and sorry it took so long to reply. I've been busy working on cars, and hopefully will even have time to build my own little turbo charged quasi-race-engine-wonder (over bored, forged crank, forged pistons, forged rods, all ARP fasteners), that likes to eat up muscle-bound push-rod wonders (it'll pick on big 4cam/4valver's too with excellent results, it's just fun stuff, then there's the corners....how's 1.3G's? )

Best,
Gary
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