Quote:
Originally Posted by JohnS_Rosamond
On the hard break in versus soft:
I was under the impression that the "softer" break in was to save the rings and cylinder bores (more even wear). If you're hard on the engine to "break in" the VVT units, you are by default sacrificing the cylinders. I would rather save the cylinders get the CEL and wait for top end to work itself out.
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You have that backwards. A hard break-in is to seat the rings — a good thing. The cylinder bores are, in fact, imprinted with a hatch-mark pattern so that they are "rough" when new. The idea is that the slightly over-sized new rings will wear against the rough cylinder walls and seat against them. The roughness of the bores actually gets smooth very quickly. Some people say the entire process is over in the first twenty miles.
With a "rough" break-in, you are using compression to force the rings against the rough cylinder walls.