Just wondering if People are running different composite seats to OEM but thought I would see what kind of valve and seat angles are out there.
3 and 5 angle seats.
Also does anyone transition their valve and if yes, at what point does it become detrimental.

 

Why run a primitive 3 or 5 angle seat?

why not run a smooth radius with combined venturi?

Seeing as you're in NZ, i'll let you in on a secret
http://www.autospeedengineering.co.nz/

Royce uses a Newen Contour, which is a CNC valve seat cutting machine. He does AMAZING work with AMAZING results.

Flick me a PM and i can talk to you about it more, Royce ported/flowed my Evo 9 Cylinder head.

Cheers, Mike

 

No doubt mike that the newen fixed system cuts a superior seat when its working( they do break down alot)
But the question is the question , i'm not going to go out and buy a newen system when there's a perfectly good serdi in the workshop.
Carbide cutting may be guilty at times for undulations and chatter , I find this rare and usually the inexperience of the machinist. I have never had a problem with seal or valve and seat longevity.

So your still running stock seats ?

.

 

Yes stock seats with stock sized valves on this head.
If i was to go bigger on the valves Royce recommended replacement seats.
He actually cut a +1mm seat onto a chamber he had already flowed and it lost flow everywhere (on an old head).

Sorry i didn't realise that you had access to all this machinery in your workshop!