Re: What the heck went wrong w/ this intake valve?
he said that as the valve turns in the chuck, if it's turned fairly rapidly, and the stone is oblong, even *slightly*, it will "beat a pattern" into the valve. Though this pattern does seem way, way too symmetrical for that. But then, if it was caused by the valve clacking around loose in its guide, why would it be this symmetrical? The only answer is for it to be harmonically stabilized bouncing around in its seat, due to some crazy just-right circumstances, OR it makes sense it was ground wrong. since the grinding chuck always turns the same frequency, and the stone is the same amount of out of round, it makes sense that all the intake valves have exactly the same pattern... weird that the exhaust valves don't show this pattern.