I'm not entirely sure what is meant by "porting." All I've been able to figure out is that it gives you more power, and I think I read that doing that, you can increase the engine to 3.1L? I don't know, I was wondering if someone could spell this out for me, and maybe say what the process and entrails and how much it'll cost. Thanks!

 

it depends what your porting, the plenum the heads....???? the only way to get a 3.1 out of a 2.8 is to replace the crank with a 3.1 to give it a longer stroke. help any?

 

porting wont increase the engine to a 3.1. it will definitly help though. every little bit helps with out 2.8's. i have my intake ported and my heads have been pocket ported. i think it made a difference.

 

what did you port your intake to????

 

But what is meant by porting? I just started to learn about working on cars and adding performance this past summer when I bought my Camaro, so I don't know much of the terminology. Thanks for the replies though!

 

what is meantby porting is making the holes that air, fuel, and exhuast go in and out of bigger

 

Yep, that's what it means. Although, you don't always have to enlarge the holes. Heads and intakes are mass-produced, and when they're cast, the ports aren't perfect. All the holes have sharp edges. Some have "casting flash"- left over metal from the casting process - sticking out into the ports. You can increase airflow just by removing the extra metal, and smoothing out the sharp edges. Also, the walls of the ports are rough. You know from driving that your car goes faster on a smooth road than a rough road, and you can "polish" (smooth out) the ports in the head to increase the velocity of the airflow. People have different views on polishing. Some say to polish both the intake port and the exhaust port. Others say to leave the intake port rough, because the roughness will help the air/fuel intake charge to "mix" better, and to just polish the exhaust port.

All three of these (smooth edges, remove casting flash, polish ports) is what's called pocket porting by some shops. You could go further than that, and re-shape the ports to change the airflow... but be careful- one bad grind and you could actually hurt airflow- bigger holes aren't always better. (laughs)

There's something called gasket matching. This is when the hole in a gasket is larger than the port in the engine component. What's done is, the openings of the ports are enlarged to be as large as the holes in the gasket.

Porting doesn't have to be done by a machine shop; but they'd probably do a better job than we could, simply because of experience. They'll also charge a lot more. For an article on do-it-yourself porting, check out http://www.sa-motorsports.com/diyguide.shtm . You can go the way of the big shops, and buy an air compressor ($300 from Home Depot for a nice one) and air die grinder ($40), or, you can buy a "dremel" or similar from tool stores- basically, an electrically-operated grinder.

To increase a motor's displacement, the way you're thinking (2.8 to 3.1), is done by boring. This is done strictly by a machine shop, they have a special boring machine to handle this. It basically removes metal from the inside of the cylinder to make it larger. A "hone" is the clean-up job of the cylinder after boring. Piston rings need a cross-hatch design on the cylinder wall to seal shut. The hone cleans up the cylinder wall, and adds this cross pattern. So if you hear of a bored & honed block, you know what they mean.

But to actually increase the 2.8 to a 3.1, we don't bore the 2.8 block out. The 3.1 is a stroked 2.8. By stroked, we mean the crankshaft has a longer "throw". Stroked engines usually make more power in the lower RPM range than a non-stroked motor, but a stroked motor will make more power than a non-stroked motor. By increasing the throw of the piston, you allow the piston to sink deeper into the cylinder than it normally would.

A 3.4 is, in essence, a bored out 3.1 block-- but, there's not enough material in the cylinder walls of a 3.1 (or a 2.8!) to bore it up to a 3.4. So the 3.4 is a whole new block, but uses a 3.1 crank.

You could hop to http://www.howstuffworks.com and read up about motors... or, click on the search button on the upper right hand corner of this screen, and search for things like boring or porting or honing or magnaflux or hot tank or etc...

Take a look at your '87's exhaust manifolds, and where they connect to the y-pipe. You'll see a little chunk of metal bolted between the manifold outlet and the y-pipe inlet. This is the exhaust "donut", it allows this connection to be gasketless. But, it's got a sharp ridge in the middle. GM took this piece and bored two holes thru it. One is a larger hole, on the side pointing towards the exhaust manifold. The other is a bit smaller, and points to the y-pipe. Between these two is a ridge. I removed this ridge with a round file (for metal, not a wood file, of course), and felt an improvement. So this is an example of porting, of what you might do inside your heads.

 

Damn Tom, dont take this the wrong way.

But I love you man.

Your tech post are the most informative posts I have ever seen.

:hail: Tom