Originally Posted by PencilGeek
I've always been curious how street car break-in differs from race motor break-in. I worked in the racing industry for a few years in my youth (still friends with all those guys) and we had a 1000hp Dyno. Whether street or racing motor, we broke them in on the dyno. According to us, the dyno was the best way to break it in because you could vary the load and run at different RPMs. Technically, a motor was broken-in when the rings were seated -- which is determined by pulling the spark plugs and looking into the cylinders with an endoscope. If the cylinders and pistons were dry (no oil), the motor was broken-in. Then we'd change the initial oil, and do the power runs. Same on street or racing motors.
So I've always wondered why a break-in needed to be 1200 miles -- when it could be as quickly as a few hours.
1. In the dyno break-in scenario you've outlined, things are tightly controlled and monitored/measured by competent people. There is no way your average consumer can do that properly driving around on the roads. And if they make a mistake, the whole engine can be trashed.
2. Other parts of the drivetrain need to be broken-in as well, which can't be done on an engine dyno.
3. Race engines are for racing. Meaning, they are designed and built differently, and have a significantly different life expectation than passenger cars.