EKHKHK56 wrote:I would still do some heat cycles before running it up on the dyno. I just let idle, blip throttle a little till warm/hot than let completely cool. A few of those at least will ease break in. Dyno is good with load, never want to rev an unloaded engine. As we know, that's when they try to fly apart. Might watch ex temp, use heat gun, big cooling fan. If exhaust port is around 750 she's at operating temp. Over 900 or so too hot.
In my opinion its best to not idle fresh rings for longer than it takes to get oil circulating. To get a good ring seal and seating requires the rings to immediately be loaded and pushed against the cylinder walls. Especially important with the narrow low tension rings. Start it on the dyno and bring revs up under a little load. When up to operating temp do some pulls. No lugging and no over revving. The first few minutes are the most important in getting a good ring seal.