- Jul 2, 2018
That's because they seat the rings on a spin-tron first. They assemble the engine except for the oil pan, fasten it to a rig that circulates oil and spins the crankshaft. After X amount of time to seat the rings, they put the pan on and fill with oil. Any "break-in" period (usually 500 miles) is to get the trans and rear end worn in.I used to think like that about dino oil for the 1st few miles. Do you know most car manufacturers use syn oil from the factory now.