Hi,

What does this exactly mean? Can you recommend a topic or any info source about this? Tanks a lot!

Alf.

 

When a car company makes a set of heads for production, the valve passageways aren't perfect. They'll have bits of "casting flash" inside; which is left-over metal, which restricts air flow. Minor head porting involves using a grinder, whether an air-powered die grinder or an electric Dremel tool, to remove the casting flash, and smooth out the metal inside the valve passageways (ports).

Metal can also be removed to widen the ports. Care needs to be taken so that too much metal isn't removed; or that metal isn't removed from the wrong spots, because you can hurt airflow if you grind the wrong areas. The pros have things called "flow benches" in which they can actually measure any improvement.

It's also possible to increase airflow way past the needs of an engine. You might find that you need more fuel pressure to compensate for extra air volume... and for us fuel injected guys, that requires a swap to an Adjustable Fuel Pressure Regulator.

You can also polish the combustion chamber. This is the part of the head that faces the pistons... it's usually "rough cast" from the factory. If it's smoothed out, the fuel and air can get a better mix.

Check out Standard Abrasive's article on do-it-yourself head porting. It's on their website, http://www.sa-motorsports.com . Summit Racing (800-230-3030) sells their head porting kit.

Your "easiest" bet would be to buy a set of heads from a junkyard, work on those, and then swap them on. You might want to have some machine work done to the heads first (hot tank = thorough cleaning, magnaflux = check for cracks, valve guides can be replaced, valves and valve seats can be cut to "bring back" proper closing).

 

Thank you very much!!