I don't have the full technical info, but basically Mobil1 had changed the additive package in their Synthetic oil, and decreased the amount of zinc but increased the amount of moly? to compensate. Zinc has great lubrication and consistency, while the moly-whatever is slippery, but has been known to cause ring seating problems...basically zinc=good, moly=poop. This change happened around the end of 06. I was told to look for "SM" on the rating circle on the bottle, and if it has "SM", it's the new junk. I'm gonna try and search google when I get a chance and see what I can find. I got the info from a reputable source, so I may be reconsidering my oil of choice

 

Rotella still has high Zinc content

 

Zinc as with other metals has increased in price phenomonally but I'd rather pay more than get less. I have been running M1 since my truck had ~1K miles, keep us posted if you can did up anything else.

 

Gonna have to look into them

BTW, after a quick search, I found out that Zinc can be detremental to cat converters...but I'm looking at a performance application stand point

 

off topic but on topic...first the first time in electric construction history diecast fittings are more expensive than stainless steel. WHY...zinc. zinc is a main ingredient in diecast. I am sure Mobil1 made this move for this very reason.

http://www.bloomberg.com/apps/news?p...d=a0lZSkF58RTA

here's an OLD article about it. 35% rise in Jan of last year. I know there has been 15% increases at least 4 times since.

 

I'm wondering if there's also some government and emissions issues that helped with the move to less zinc...but I'm sure that being able to make their product for less $$ and sell it for the same price is probably the biggest factor...

 

Another component is emergency lubricants. This is typically zinc, phosphorous, and molybdenum. These chemicals are present in case your oil film completely breaks down, due to extreme temperatures or pressures. These chemicals are supposed to be a last resort defense against metal to metal contact in your engine. Oil companies are cutting back on zinc and phosphorous, as these metals are hard on your catalytic converters. They're substituting molybdenum disulfide, which lowers friction and improves gas mileage.

 

ahhh "molybdenum", that's the word I was looking for. I wonder how much this info applies to already broken in engines where the rings are already seated. I got the info from my father who is a race engine builder, and breaks in and dyno's every engine that goes out of his shop. I would have gotten deeper into the conversation with him, but it was a family gathering and alot was going on...

anyway, I found some interesting stuff in the few minutes that I searched:
http://www.repairfaq.org/filipg/AUTO/F_oil_facts.html
(don't know the source)
http://neptune.spacebears.com/cars/stories/mobil1.html
(another unknown source)

Is "patman" still the oil guru over at LS1Tech? I might try and search some of his threads....

 

I have actually been reading about this for a couple months. The additive package was changed essentially for the automakers, to help them with the emissions standards. The zinc was what everybody seems to be talking about, mainly in flat tappet cam apps. There were a few oil types that kept the old package, as Moregrip stated, Rotella is one, and some type of Pennzoil I think. It was in either a Hot Rod or a Car Craft mag a couple months ago. I will try to find it in the morning when I get off, and add some more info..

 

I guess I'll be sticking with Royal Purple.