Ducati valve seat shape - radiused or sharp angles?
Posted: May 23rd, 2007, 1:07 am
I'm sat here wondering what benefit there is to having radiused exhaust seats over say, a 75 degree that I have never tested ?
Radiused seats might work on very big valves (eg: large V8) but on smaller ones like yours I have found the flow to be worse than sharp edged angles.
The reason I deduced was that an aerodynamically correct radius was not achievable on a seat of small proportions and the airstream was fully breaking away and becoming turbulent over the curve, whereas with the sharp angles the airstream breaks away over the edge and then recovers its stability before it meets the next change of angle.
Try it and see if it works on your Ducati head is the only real solution.
GC