When looking for performance gains from your engine the cylinder heads are the area where you will want to concentrate your efforts for the most performance gains.
A mixture of air and fuel flows through the cylinder heads into the cylinder where it is converted into energy and transferred to the wheels. The more air/fuel mixture you can get into the cylinder the more energy will be made. Stock or “as cast” heads have many restrictions in the port areas which can be removed and reshaped to enhance the airflow into the cylinder. These modifications can be performed by a professional or by your average hot rodder in the garage at a much less expense. Many hot rodders enjoy doing their own work.It’s not easy but with the proper tools and patience it can be done and be very rewarding when done yourself.
Typically two-thirds of the airflow gains to be made from an “as cast” head are found from a half-inch into the combustion chamber to about a half-inch past the port’s guide boss. Basically this can be described as “deep pocket porting.” It finds the fastest, easiest gains and, other than cleaning up, should represent the limit of your initial porting efforts. The valve seat and the approach to it and from it are more important than the port itself.
Take it easy Your first port job should consist of blending the seats into the port,skinny down the guide bosses and blend the radius areas in the bowl for a smooth transition from the intake runner.after this just a nice cleanup of the ports and chambers with course sanding rolls will do. Remember port shape is important not shine.
Proper Tools
1. Air compressor and air powered die grinder
2. Porting kit and 60 to 80 grit sanding rolls
3. Carbide cutters
4. Shop vac
The tools needed for this are very basic and a quick search of the internet for “head porting tools” will provide you with many choices. Most companies will have a variety of head porting kits for you to choose from.
Proper machining
When you have finished porting your heads you will need to send them to an automotive machine shop where a machinist will check the valve guides for proper size,grind the valve faces and valve seats and check the heads surface for flatness.The rule here is that poor valve seats produce poor results almost regardless of how good the port might otherwise be. A good valve job is an important part of good performance so don’t skimp here.
Safety First
Always wear safety glasses and a dust mask when grinding on your heads. You can use shop vac to suck the debris out of the ports as you work.
Patience
Porting your heads can be very time consuming so allow yourself plenty of time.
Practice
If this is your first attempt at porting it would be a good idea to get yourself an old junk head to practice on and get the feel of things first.
By: Steve Boyce
About the Author:
For more information and ideas on cylinder head porting visit http://www.squidoo.com/How-To-Port-Cylinder-Heads
