CNC Mill Mark Removal in Intake Port

RustyRatRod said

So after readin all this, I'm still kornfrooshed. Is there a consensus as to which way is better? Smooth or rough ports? Or is it combination dependent? Or some other magic fairy dust?

Click to expand...

Rough is always better. That’s according to Darin Morgan and Larry Meaux.

The outlier is CNC step over. I’ve seen that so coarse you couldn’t even read the manometers.

I can’t remember what the CFM loss was but it was big.

I’ve never seen a burr finish do that but I would suppose it’s possible to get that too rough.