porting heads

[AdamG]

I got a chance to read some of the links earlier. I am going to finish reading the rest tomorrow.

[Viper]

With aluminum use coarse grinding stones and sand cartridge rolls to shape aluminum do not use carbide burs and cutters even ones designed for aluminum removes too much metal too fast. Keep the cartridge rolls moving slightly or it will create dips and ridges touching and shaping. Clean up the ports don't try to enlarge them or change their shape drastically especially on the tops and floors you'll find the water jackets. On the sides of the intake if you try to straighten the curve in the pushrod pinch are youll go through the casting to daylight. Try to make all the ports identical that way you get similar power from each cylinder.

The reason they say not to enlarge intakes to gasket match is porting shops pay money to their employees to do as much in as little time as possible. General administrative costs, shop support, and overhead reduce these = greater profit margins.

Not matching the ports to the gaskets but just the openings(1/2to1") along with the opening on the intake insures even consistant flow to each cylinder. Think of the port like a funnel or a cold air intake K&N and Moroso start large and unrestricted taper down to increase velocity and smooth transition past valves into combustion chamber. Porters use templates to hand port chambers CNC use flow tested heads digitized into the computer to replicate the template or pattern design.

Use a Dremel or 1/8 inch tool to smooth valvejob diameter into ports and shape valve guides. Use 1/8 and 1/4 electric or air die grinder to shape debur the ports. An electric varible light dimmer switch can be used to control the speed of the porting tool. Use a slower speed on aluminum it cuts faster and remove the valves.
Place clamp on light to see your work inside the ports. Use 2x4s to hold the heads in positions to port. Lastly do not use glasses to protect your eyes I almost lost an eye from this. Use Goggle or a face shield and do not breathe in the grinding material kleenex in nose or respirator. Most guys want to make the intakes larger but the exhaust are easier to do and flow less. Results just polishing exhaust ports and manifolds or adding headers makes the engine rev much faster I've done this on lawn mower engines 3 wheeler atv's 4cyl engines inline 6cyllinders v-8's and radio controled airplanes.

DON"T try to ENLARGE the PORTS iv'e ground through so many things if I get carried away or distracted just clean smooth and polish.

Match and remove imperfections in the castings.