ATV Florida Forum

what is the concensis of the masses. over the two applications.  Manual Port work or Extrude hone process

I think you could ask 1000 porters this question, and you would get 1000 different answers or scenarios.

I have never been a big fan of Extrude porting on standard cylinder heads. Even though the idea of how it works sounds good, myself as well as the many people I have been taught by and the hours of schooling say that it would not be the ideal method in most cases. CNC with a hand finishing would be the best IMO,but I still believe hand porting in most cases will produce some of your best gains more so in our ATV or small engine applications. The certain areas of a port that need more attention to get the potential gains that one would be looking for are more easily addressed by hand at the discretion of the porter.

Obviously, everything I am stating is just an opinion, but for example, The substrate that is used for extrude porting has mass. When this mass is introduced into a port or other opening, It will vary in size, shape,speed and density. If you were to send the substrate down a passage that would have an "L" shape for example, there would be more material removed in the corner or depending on how it is clamped on the machine, gravity naturally pulls down, so that will have a drastic effect as well.

Hope I made some sense. I am attaching a picture of what I mean about the mass not making a proper port. If you look in the upper left corner of where the substrate is coming out of the intake, you will see an AIR GAP. so what's really going on inside?


Mike



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POINT WELL TAKEN ;)

that's some good info Mike, thanks

Yep hand porting all the way. I've seen some cylinder heads (car) that were ported that looked better than extrude hone/CNC porting.  Once a casting is made (stock) doesn't always mean it everyone off the assembly line is the same.  -Mark