This is a very interesting conversation to me. I said this on the "other" Ford Truck Forum. It is just my personal experience. I am just going to leave this here as information from my own experience and tell me what you think....bear with me
My Superduty is my fourth 7.3...for the last two months, my truck has had a VERY slight hiccup.....not even noticeable to anyone but me because I drive it every day. I checked everything we usually do before my trip (UVCH pins, OHM injectors, injector torque, etc). Based on experience, I got to thinking about the new CK-4 oils and noticed that the odd idling/running issue coincided with the CK-4 changeover. I know that zinc and phosphorus are pretty important in diesels, especially our older 7.3s, so it got me thinking that maybe I am having an oil issue (had so many in the past, I figured WTH). So, I went to Supertech 15w-40 to put a CJ-4 back in there and because there VOA
shows a very robust additive package. I was going to go with Tractor Supply (same manufacturer) that a buddy of mine uses, but no stores in my area at the time, so Walmart it was. I changed it in the parking lot. Fumoto valves make things easy
.....annnnnyways, noticed on start up and about a minute of idling....different truck....or I should say, same truck I was used to. I wasn't convinced until I towed 200 miles, stopped for fuel, and it was idling so smooth and quiet with no gearshift shake or odd misses.
Sooo, here is my own personal geek theory. Our engines are driven by the HEUI
. If the newer CK-4 oils, such as Rotella, have less of what is needed, such as zinc, phosphorus, magnesium, it possibly creates "flat spots" for the lack of a better term. If an injector, driven by oil to fire, gets a flat spot, it performs subpar or slightly misses/bobbles. It's the only thing that makes sense to me. The rest of my trip after the oil change produced a truck that performed well under WOT
loaded pulls, and idled well when stopped for fuel on cool down. I have also experienced this kind of issue with other oil on this truck that was subpar, but it was even a bigger issue and very noticeable right away. I could be crazy, have placebo effect, or whatever, but it seems to be a real world problem. Maybe my truck is just a picky beeyatch.
Anyways, thanks for letting me geek out on oil for a bit. Let me know what you think, or anyone else if they want to chime in.