Break in Oil why do some vehicles come from

[hammersley]

the Factory with synthetic and I was told by Cummins NW that one should wait for 20-30,000 for breakin to occur. Is this just opinion and or fact? And what about the cars like Corvettes and I think some BMW's and others come brand new with synthetic.....

 

[Forrest Nearing]

different tolerances within the engine

 

[nickleinonen]

differernt manufacturing procedures too. . most of the break in was seating the rings into the cylinder walls/liners. . many manufactures now plateau hone the cylinder walls/liners after the cross hatching to make the rings seat quicker

 

[jwilliams3]

Wait 10k and then go for it.

Thats what I did.