Splayed Valve Heads Porting
Posted: Tue Apr 04, 2023 3:45 pm
I have been binging the David Vizard vids recently, and I was very intrigued by his 5 video series on head porting.
1: https://youtu.be/eLJU1h-raUg
2: https://youtu.be/eLJU1h-raUg
3: https://youtu.be/gIPKoH57mTA
4: https://youtu.be/mQwon4Gfzfo
5: https://youtu.be/V21BdS_Rvgw
He says he gets really good results by opening up the port on the same side as the cylinder wall because it directs air to the center of the cylinder, but he is working with small block and big block motors. With the splayed valves that already point the air to the center of the cylinder, I imagine that opening up both of the port sides evenly would be more ideal.
Other items mentioned include slowing down air on the port floor so it can better make the tight radius turn it needs to go around, and he suggests creating a teardrop shaped bump on the floor of the port. It is interesting as it is very similar to the shark fin vane on the 2.8 intake ports. He has a few other suggestions for the port floor as well.
He also says that the greatest restriction in the airflow is going around the valve, and makes a point to open up the bowl to 88-92% of the diameter of the valve. He grinds and shapes the valves as well, but our splayed valve 60*V6 heads already have valves that are shaped like he re-shapes his. In addition he shows just how much a good 3 angle valve job and a 30* valve seat can improve flow by the valve.
After watching his videos I am extra impressed with the intake port designs of my LZ9 heads, the coffin shape port really supports the way that the air wants to flow, and this is accomplished with the splayed valves that also have the benefit of pointing both valves at the center of the cylinder which is supposed to seriously help flow since there is very little shrouding of the valves and due to direction of airflow.
I ported my heads very similarly to how he suggests, and when I was porting mine, I was trying to use the same reasoning he does, "how does the air want to flow?"
Wanted to open this topic up to discussion as it is very interesting.
1: https://youtu.be/eLJU1h-raUg
2: https://youtu.be/eLJU1h-raUg
3: https://youtu.be/gIPKoH57mTA
4: https://youtu.be/mQwon4Gfzfo
5: https://youtu.be/V21BdS_Rvgw
He says he gets really good results by opening up the port on the same side as the cylinder wall because it directs air to the center of the cylinder, but he is working with small block and big block motors. With the splayed valves that already point the air to the center of the cylinder, I imagine that opening up both of the port sides evenly would be more ideal.
Other items mentioned include slowing down air on the port floor so it can better make the tight radius turn it needs to go around, and he suggests creating a teardrop shaped bump on the floor of the port. It is interesting as it is very similar to the shark fin vane on the 2.8 intake ports. He has a few other suggestions for the port floor as well.
He also says that the greatest restriction in the airflow is going around the valve, and makes a point to open up the bowl to 88-92% of the diameter of the valve. He grinds and shapes the valves as well, but our splayed valve 60*V6 heads already have valves that are shaped like he re-shapes his. In addition he shows just how much a good 3 angle valve job and a 30* valve seat can improve flow by the valve.
After watching his videos I am extra impressed with the intake port designs of my LZ9 heads, the coffin shape port really supports the way that the air wants to flow, and this is accomplished with the splayed valves that also have the benefit of pointing both valves at the center of the cylinder which is supposed to seriously help flow since there is very little shrouding of the valves and due to direction of airflow.
I ported my heads very similarly to how he suggests, and when I was porting mine, I was trying to use the same reasoning he does, "how does the air want to flow?"
Wanted to open this topic up to discussion as it is very interesting.