Do not break in an engine on synthetic oil. Just trust me on this one. What works in an OE engine plant will NOT work in your driveway.
I sold roughly $22 million per year in aftermarket piston rings during my time at Federal-Mogul. At one point I managed the Sealed Power and Speed-Pro ring product lines concurrently. The man who worked with me was one of the nation's foremost ring design engineers, and I believe he would agree on this. Over those years a fair amount of consumers and racers would call in with ring break-in issues. A good percentage of those had used a sythetic oil - and often experienced problems for the first time doing so. I'm not talking about Saturday night racers either - some of these were very well known professional shops.
An OE plant uses a straight vertical travel power hone on cylinders - not the arc travel hone common to the aftermarket. Their cylinders are rounder, more consistantly, than our's. They control the oil chemistry, the fuel chemistry, and the fuel mixture on fire up - and none of these may be the same as what you or I can purchase.
Synthetic on break-in is taking a risk with no reward. why would anybody do that?
