Porting specifics, porting transition from runner?
 

Hey guys, just doing some practice porting on some old junk irons and i have a few questions. First of all this is just the rough cut, only using a carbide bit, i still have alot of stone grinding and sanding. I want to know if i should smooth out the coner transition from the runner to the port as indicated in the pic, and also if i should smooth out the roof out the outer edge. for my first port i think its turning out ok, I was amazed at just how fast you can port with an air die grinder and a double cut carbide bit. and its my understanding that I shouldn't change the size of the runner, is this true?

Thanks, Matt


http://i54.photobucket.com/albums/g8...ello/ports.jpg

You should pay just as much attention to the port runners as you do to the port opening itself. Having a whopping big port and small runners really hurts flow. Ideally they should have the same cross sectional area. I paid particular attention to the opening edge of the port and removed some of the radius where it blends into the runner so the airflow has more of a direct shot into the engine.

Have you spent any time in the 'Engine building and porting' section at NoPistons? You will find more info than you can digest in a week over there. Best source for porting there is.

^ what both of those guys said.