Head Porting for the Do-It-Yourselfer
Taken from the technical staff of
Standard Abrasives Motor Sports Division at sa-motorsports
Here's an interesting head porting fact: In many cases, the greatest performance gain per dollar spent comes upon application of basic porting procedures to a production cylinder head.
These basics can be done by any do-it-yourselfer, even those with no porting experience, using the Deluxe Porting Kit and the Gasket Removal Kit (part nos. 260001 and 260005) from the Standard Abrasives Motorsports Division, along with a die grinder and some common hand tools.
There is a significant difference between basic head porting for a street-high-performance or weekend racer application and the very complex cylinder head work you see in a Pro Stock drag race motor or a NASCAR Winston Cup race engine. Doing full-on race heads requires the services of an experienced cylinder head professional, so Pro Stock, Winston Cup and similar heads are best left to experts. Basic head porting, however, is easy...so easy that even beginning hot rodders can do it well.
Basic cylinder head porting will improve the performance of any production cylinder head by removing flaws that come through mass production. Basic porting does not attempt to correct any design or engineering deficiencies. Once your porting project turns to that, you're beyond the scope of basic porting techniques.
Why is basic port work important to your engine's performance? It reduces the restriction in the engine's intake and exhaust tracts. Reduce that restriction and you let more air into the cylinders. If you have more air, you can add more fuel. The result is increased horsepower.
Most of the work in a basic porting project is focused on reducing those restrictions which are caused by: 1) "steps" that may obstruct intake air flow as it transitions from the intake manifold to a smaller intake port entry in the head; 2) casting bumps, ridges or other marks, such as those you may find on port floors or roofs; 3) sharp edges, such as those you will find around the valve guide bosses at the top of the valve pockets; and 4) the point where the intake port floor curves down to the valve seat.
Basic porting, while somewhat time consuming, is not hard work. It takes about 10-12 hours to do a set of average V8 heads. Some week nights and a weekend invested in your heads and your basic porting project will be complete.
Continued...
At this point I have left out some information which may be seen as helpfull by others concerning the materials used, techniques, cast or Al heads, and matters of safety. If you would ilke the information it can be found at the link provided above as well as pictures to better demenstrate the methods used.
Continued...
Step 1: Removing Old Gaskets and Marking the Intake Ports
Even though the heads have been cleaned, the gasket and deck surfaces should be conditioned to remove all traces of old gaskets, paint, gasket sealer, corrosion and dirt. The use of a putty knife or scrapper for this purpose is not acceptable because neither will clean those surfaces completely. If your heads are aluminum, a putty knife or scraper may even damage those surfaces.
The Standard Abrasives' 3-inch Gasket Removal Kit is the proper way to condition the gasket surfaces without damaging them. It contains surface conditioning discs for use on cast iron and aluminum along with a holder pad that attaches to your die grinder.
Disconnect the grinder, install the Standard Abrasives' surface conditioning disc holder into the chuck and tighten the nut. The conditioning discs use Standard Abrasives' unique Soc-AttTM locking system, so installation is as simple as a twist of your wrist. Reconnect the grinder, put on your eye protection and gloves, then start removing the gaskets the easy, Standard Abrasives way. Once the gasket surfaces are down to bare metal, disconnect the grinder and remove the conditioning disc set-up.
In most cases, your port work will start with enlarging the "port entry" area to the size of the openings in the intake manifold gaskets. Later, you will reshape the ports in the intake manifold to this same size.
To ensure the head port entry and the intake manifold port end up the same size, you scribe an outline of the intake gasket openings on the head and the manifold. Machinist's bluing is used for this. Apply it to the intake gasket surface around the intake ports and allow it to dry. Place the new intake gasket in its normal position and hold it with manifold bolts. Scribe the inside perimeter of each intake port onto the gasket surface of the head, then remove the gasket.
Pay close attention to the position of the gasket on the head. If it is upside down or backwards, your scribe marks will be in the wrong locations. That will cause a serious problem with your port work.
Taken from the technical staff of
Standard Abrasives Motor Sports Division at sa-motorsports
Here's an interesting head porting fact: In many cases, the greatest performance gain per dollar spent comes upon application of basic porting procedures to a production cylinder head.
These basics can be done by any do-it-yourselfer, even those with no porting experience, using the Deluxe Porting Kit and the Gasket Removal Kit (part nos. 260001 and 260005) from the Standard Abrasives Motorsports Division, along with a die grinder and some common hand tools.
There is a significant difference between basic head porting for a street-high-performance or weekend racer application and the very complex cylinder head work you see in a Pro Stock drag race motor or a NASCAR Winston Cup race engine. Doing full-on race heads requires the services of an experienced cylinder head professional, so Pro Stock, Winston Cup and similar heads are best left to experts. Basic head porting, however, is easy...so easy that even beginning hot rodders can do it well.
Basic cylinder head porting will improve the performance of any production cylinder head by removing flaws that come through mass production. Basic porting does not attempt to correct any design or engineering deficiencies. Once your porting project turns to that, you're beyond the scope of basic porting techniques.
Why is basic port work important to your engine's performance? It reduces the restriction in the engine's intake and exhaust tracts. Reduce that restriction and you let more air into the cylinders. If you have more air, you can add more fuel. The result is increased horsepower.
Most of the work in a basic porting project is focused on reducing those restrictions which are caused by: 1) "steps" that may obstruct intake air flow as it transitions from the intake manifold to a smaller intake port entry in the head; 2) casting bumps, ridges or other marks, such as those you may find on port floors or roofs; 3) sharp edges, such as those you will find around the valve guide bosses at the top of the valve pockets; and 4) the point where the intake port floor curves down to the valve seat.
Basic porting, while somewhat time consuming, is not hard work. It takes about 10-12 hours to do a set of average V8 heads. Some week nights and a weekend invested in your heads and your basic porting project will be complete.
Continued...
At this point I have left out some information which may be seen as helpfull by others concerning the materials used, techniques, cast or Al heads, and matters of safety. If you would ilke the information it can be found at the link provided above as well as pictures to better demenstrate the methods used.
Continued...
Step 1: Removing Old Gaskets and Marking the Intake Ports
Even though the heads have been cleaned, the gasket and deck surfaces should be conditioned to remove all traces of old gaskets, paint, gasket sealer, corrosion and dirt. The use of a putty knife or scrapper for this purpose is not acceptable because neither will clean those surfaces completely. If your heads are aluminum, a putty knife or scraper may even damage those surfaces.
The Standard Abrasives' 3-inch Gasket Removal Kit is the proper way to condition the gasket surfaces without damaging them. It contains surface conditioning discs for use on cast iron and aluminum along with a holder pad that attaches to your die grinder.
Disconnect the grinder, install the Standard Abrasives' surface conditioning disc holder into the chuck and tighten the nut. The conditioning discs use Standard Abrasives' unique Soc-AttTM locking system, so installation is as simple as a twist of your wrist. Reconnect the grinder, put on your eye protection and gloves, then start removing the gaskets the easy, Standard Abrasives way. Once the gasket surfaces are down to bare metal, disconnect the grinder and remove the conditioning disc set-up.
In most cases, your port work will start with enlarging the "port entry" area to the size of the openings in the intake manifold gaskets. Later, you will reshape the ports in the intake manifold to this same size.
To ensure the head port entry and the intake manifold port end up the same size, you scribe an outline of the intake gasket openings on the head and the manifold. Machinist's bluing is used for this. Apply it to the intake gasket surface around the intake ports and allow it to dry. Place the new intake gasket in its normal position and hold it with manifold bolts. Scribe the inside perimeter of each intake port onto the gasket surface of the head, then remove the gasket.
Pay close attention to the position of the gasket on the head. If it is upside down or backwards, your scribe marks will be in the wrong locations. That will cause a serious problem with your port work.
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