Porting and polishing heads

[GoBears]

When trying to find decent mods for my 3.8, I always read and hear intake and exhaust as the first steps. These will be complete in a month. I also read alot about getting the heads ported and polished. I understand what the polishing does for flow, but could someone explain what porting is and how it helps? Also what kind of bill should I expect from a shop to do this porting/polishing for me? I read it can add 30+ hp to a 3.8L engine. Thanks in advance.

[DaMoNe6969]

Porting, is where they widen the intake and exhaust ports on your head.. They take away some of the material, and smooth out the sharp edge to a more tapered edge to allow more air to flow, and flow it smoothly... Polishing also helps to smooth out airflow.. Im not sure what it'l cost you.. everywhere is different I guess.. If you've had machining experience, or your handy with a dremel or similar rotory tool, you could do them yourself.. But if you are, pick up a junk head at a wrecker and practise on it first because it is very easy to grind away too much material and cut into your water jacket or anything like that.. You can also buy porting kits that come with all the attachments and instructions..

Make sure that if your exhaust ports are ported, than your exhaust manifold should be ported to match, and you'l haveto mark out your manifold gasket and cut some of it out also to allow for the wider port.. Same with the intake side..

Read these

http://www.sa-motorsports.com/diyport.htm

http://www.gtiworld.fsnet.co.uk/porting.htm

It is a relativly cheap way to get some decent power out of the 3.8's cheaper if you can manage on your own..

[4onFloor]

damone is exactly right, except you dont port and polish the intake ports. that rough texture on the intake ports is essential to mixture attomization. now you can port match the intake side, that's where you take your intake gasket or make a template from your intake manifold and grind a chamfer or bevel on the edges of the intake ports to match the intake manifold port size so theres no air restriction, and i've heard you can gain like 50cfm by doing this. you can easily port and polish your exhaust ports with a die grinder and a stone, or even use a dremel but it takes longer.

[GoBears]

Thanks alot for the replies. I am definately going to look into getting this done. Being without a garage, I am going to have to have someone else do it. Thanks again.

[ridge_runner]

yea if you were to do it yourself you would have to have some experience, or you could really mess things up

[4onFloor]

eh i've done it myself without prior experience. it's pretty much just common sense

[ridge_runner]

well you could slip up or something, well i guess it depends what kind of tip your using

[4onFloor]

with cast iron heads it'd take a lot to screw those up. aluminum heads on the other hand i would definataly have proffesionaly done. or can even port aluminum heads?

[Dober89]

Having a first time do it yourselfer port and polish his own heads would be a little different than having a professional do the job for you. The professional guys know their stuff and know where to spend a little extra time to open an area up to greatly improve flow.

[4onFloor]

cant learn if ya dont try. there's plenty of sites dedicated to the how to's and do's and dont's when it comes to porting

[Pewter'01SS]

You can port the intake runners to be smoother than stock. Ideally, you want a 60 - 80 grit finish on the intake side.