Mark and Tom - here's an oil related break-in question for you. What do you think about using one of the break-in additives? I run Red Line in my GTS, and I notice they have a break-in additive that's supposed to be appropriate for engines that have synthetic as their first-fill. Hopefully my ACR is going to be built by summertime, and it comes with a synthetic (Mobil or Quaker or whatever) factory fill. What I typically do is change the oil after 200 or 300 miles, and I was wondering if it might make sense to put the break-in additive in when I take delivery and leave it in there for the first few hundred miles to help seat the rings, etc. Any thoughts, or should I just drive it and change the oil like I've always done in the past?
The break-in additives
should be simple, high doses of zinc dialkyldithiophosphate (ZDDP) which is the antiwear additive that the OEMs claim harms the catalyst (after 100,000 miles). Using such an additive would be fine, and frankly is a necessity in a flat tappet, high lift cam build-up. It is not required in an engine with roller lifters, which is why OEMs can recommend low ZDDP oils in new engines.
Some cam manufacturers use a high dose of a molybdenum friction modifier instead. This is technically incorrect, since rather than assist break-in and smooth out parts than come in contact, it is artificially delaying break-in until you remove the friction modifier with the oil change. Read the label. Phosphorus good. Moly bad. Calcium, boron, magnesium OK but not preferred.
I'm not entirely convinced the average break-in additive is a good product. I would much, much rather see you put diesel oil in it. Diesel oil has more ZDDP than passenger car oil.
There is no reason synthetics should have different break-in characteristics than a mineral oil. Corvette, Viper, Cosworth, AMG, etc, etc, fill with synthetic and off they go. The myth of using mineral (or not synthetic) came from using non-detergent (non additive!) oils. These API SA or SB oils are only available in mineral oil, but people associated break-in with mineral base oil and forgot that the oil also had no additive in it.
Martin, I would give you two choices. (1) Change immediately to the 5W40 or 15W40 diesel oil and leave it in for 5000 miles, or (2) drive it for a few hundred miles, with a few trips long enough (hour) to ensure the oil got up to oil thermostat temperature, drain it (and save it for your lawnmower.) The heat issue is because ZDDP needs higher temperatures (when the oil gets thinner) to activate and begin the protection function.
Look at the tens of millions (fewer now) of engines built annually that just drive and go 5000 miles - they aren't sitting and smoking on the side of the road and they last longer than most Vipers ever see on their odometer. (Not picking on you at all, just remembering the oil company joke that cars are driven to the junkyard these days...)