Why not radius the valve and seat?
 

I've heard of 3 and 5 angle valve jobs and such, but I was just thinking, why not put a smooth radius on the valve and a matching one on the valve seat?
In my head, it seems like the air would flow better over a smooth radius than 3 or 5 sharp angles.
Has this ever been tried? It might be a bit of a headache making the tooling to do it, but I'd think for a serious race motor that it would probably be well worth it. Then again, maybe it would be worse. Just another case of me thinking up stupid ideas :rolleyes:

Great idea, except that the valve needs a more defined seat to help keep it from "wondering" side to side, wearing out the guides prematurely.

Take care,
-Chris

PKRWUD is right. If the valve had a radius for a seat, it would definitely wear out prematurely. That is the purpose of a multiple angle valve job, to have a more defined seat. I think this is right, but don't take it to the bank. I could see it helping airflow a little. Anyway, nothing wrong with your idea. But a radius will wear out the guides quicker than the multiple angle seat.

easy fix: Titanium valve guides :D

if it is used on a race only motor that is rebuilt every so often then I would think that it wouldnt be much of a problem. But oh well

MM&FF has a discusion on this very thing.
This is what they said:" For short cammed motors, radius the fornt face of both the inlet and exhuast but for long cams(over 280 seat duration) only do the exhaust. Both valves should be back-cut 30 degrees to leave a seat on the valve about 20 thousandths wider than the seat in the heads."