SM Head Modifications on a budget

[PRH]

At higher lifts(velocities), I can see where the radius might be deflecting the air stream out sway from the edge of the valve……..where the thicker margin allows it to ride along that length before making the turn into the bowl.

One theory anyway.

 

[Earlie A]

This may be the last test prior to taking on Herman's forehead. I don't know of anything else to try other than a different valve job. To get a steeper top cut (which I think would help the separation issue), the valve would have to be sunk which would affect the throat, etc, etc. I think that will have to wait.

This test is the last thing associated with the first 5 steps, but it's really like step 5.5. For this test the ridges in the chamber that were created by the 15 degree plunge cut were blended away. The plug side was smoothed first and flow tested. There was virtually no change in flow. The short side corner was then blended away. The sharp inside corner was a little problematic to get rid of. In fact it is not totally gone. The finish cut in the chamber is a burr finish. No sanding rolls were used.

Final flow results after both blendings are shown. These blendings were a little helpful at low lifts and again at high lifts. There is an apparent decrease in the 0.500-0.600 lift range. With all the instability in that range I think these should really be ignored. All that is happening there is that the sharp ridges are helping to delay flow separation. The ridges are helping the port hold on a little longer before the balloon pops and the flow fully jumps the valve.

I guess it's time for some SSR work.