I have an old Italian motor bike with 30° valves.
I always wondered why they did this(The Alfas have them as well)
Is there any advantage? Or is it an adaptation for quick setting the valve/seat combination?
Thanks,
Dirk/Antwerp
30 deg valve/seat angles are often used on lower speed engines (such as diesels) though not exclusively, with moderate cam events, where the superior low lift flow (over a 45* seat) can improve torque.
I don't know of any quicker seating benefits , that I assume you're alluding to.
"It's not always a case of learning more, but often of forgetting less"
Many domestic US engines used 30 degree seats on the intake and 45 degree seats on the exhaust. Cylinder combustion pressure has a different amount of sealing force on different degree valves as well. There is more force on a 45 degree seat than a 30 degree seat.
Franz
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If valve seat wear was a problem in development, then changing 45deg seats to 30deg seats would increase the sealing area without having to change the inserts/head....