Why cylinder head porting

Tons of DIY or miracle cure products are on the market, claiming to pull a few extra ponies in just a couple minutes. If you really want to see gains, be prepared to put in some hours with your car. Porting your cylinder head is a car modification you can make to improve performance. An engine is, in the most basic explanation, a large air pump.

The more airflow into and out of the engine, the more power you can produce within reason, of course. On some V8 engines such as a Chevy LS1 engine, gains of to horsepower have been made — some even claim up to extra horsepower!

These are the basic steps to porting your cylinder head. Most 4-cylinder, 6-cylinder, and 8-cylinder engines follow roughly the same process. Take each step slowly. Paint the area around the intake ports with Dykem. Roycroft says he always starts with the valve size. Once he has a valve size that will work with the port and the engine, he works backwards from there. Then it goes on the flow bench to check air speed and the cfm, etc.

Air speed, in my opinion, is more important than cfm. The bowl area, and especially the short turn radius on the port floor, are critical to airflow in most cylinder heads. This is also the area of the head where porting experience comes into play, since changing the radius of the short turn and the overall shapes within the bowl area can have a big impact on the angle the airflow enters the combustion chamber at, which can in turn have a big impact on the combustion event itself.

Advertisement Common Mistakes Remember, if you start conservatively with the amount of material you remove, you will avoid a number of potential issues. However, not everyone ends up being conservative, and the last thing you want to do is blast through into a water passage and have to get the head repaired or toss it in the garbage. Depending on the seat angle and what type of cut angle you use is going to determine how big or how small you can get away with on the throat size.

Those angles are there on the valve job to help that air turn. If you can do that, from there, a tool like the flow bench will help you greatly. I can have a port that I think looks good, I can grind it out and think that it will be badass.

I never would have known that if I had not stuck it on the flow bench. That is the absolute most important aspect of it. Components: Speed of Air Engine Technology. Shop Solutions: Shop Solutions October Magazine Current Issue Past Issues. Connect with us. Advertise Subscribe Contact Us.

ICE vs. By Greg Jones. Since every cylinder head is different, learning how to improve airflow characteristics involves a lot of trial and error and many hours on the flow bench to determine if port shape changes have made a difference.

The Value of a Good Valve Job In general, the most critical areas when porting a cylinder head are those which pass the most air at the highest speed and for the longest duration. Today, a three-angle valve job is standard procedure, and the first angle cut is the throat cut, which is typically around degrees. Hand-Porting vs. If you need to make changes to a port using a CNC machine, you can digitally make those changes and run the program. Common Mistakes Remember, if you start conservatively with the amount of material you remove, you will avoid a number of potential issues.

A word of caution before you start hacking your cylinder head apart with a drill however — this kind of modification should only be performed by someone who has past experience doing so or by handing the head into a professional shop to be machined.

With an experienced touch and some well-placed grinding however, you can gain some ever-needed additional horses back under the bonnet, through what is essentially just a clean-up! Please confirm you agree to the use of tracking cookies as outlined in the Cookies Policy. Sign in or register. Michael Fernie 5 years ago. Remind me later. Share Tweet Email Whatsapp. The anatomy of a cylinder head, with the corresponding valvetrain above. Head porting is a long, tricky and intricate process, but the power gains can be worth it in the end.

A cylinder head setup for testing on an air flow bench. Port matching can include shaving material from the exhaust and inlet manifolds instead of the cylinder head.