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The single cylinder and its 4 ports shown in this article represents about 5 hours work. admittedly it was my first attempt at porting so i took things a little slow, and was probably over cautious, but in the words of a professional head porter "fuckin time consuming isn't it!". the images below demonstrate the approaches i took to porting the short walled (casting #11) 7mge head. i've tried to take the images as best as possible to show the areas of most interest. each series of images represents the worked port, followed by its stock equivalent, and i've tried my best to keep the proportions between the images consistent so you can see the effects more clearly. see the captions below each image for a full description.

for a comprehensive technical introduction to the principals head porting, and a practical guide to head porting techniques, see the links page available from the main menu.

image above:: oblique view of the intake ports. things to note include: removal of the machined shoulder present below the seats in both ports- a results of factory valve seat installation. grinding of the seat itself, right up to the 45deg angle of the seat shoulder. significant rounding, blending and smoothing of the short side radius. blending and radiusing of the port divider. this divider was also narrowed slightly at its leading edge, but not significantly, leaving it rather blunt.

image above:: this low view of the intake best shows the improvements made in the short side radius' curve and contour. notice how bad the machined shoulders are below the seats in the stock port. it is also a good view to note how the seats themselves have been ground right up to the 45deg cut (note the shine).

image above:: despite these two images being in slightly different proportions, you might get some idea how much larger the worked ports now are. its also a good view to appreciate how the bowl has been blended into the valve guide base, how the roof and walls have been contoured around the 'ramp' leading up to the valve guide, and how the guide itself has been countoured. you may also notice that the 2 'mounds' on either side of the valve guide in the stock port have been removed, and blended into the roof and bowl.

image above:: this shot of the bowl basically shows a mild increase in bowl volume, but far better blending, both at the seat, and with the valve guides. its also a good view to appreciate the grind up to the 45deg cut on the valve seat, and the overall increase in port size. notice the small steps present in the valve seat in the stock head.

image above:: exhaust port main view. note the knife edging on the finished divider, this is an effort to reduce turbulence as the two air streams come back together.

image above:: low angle exhaust valve port view, again, note the LARGE increase in port diameter, as well as the improvement of the short side radius - in particular, the removal of that obvious machined step.

image above:: directly above, exhaust port valve view. note the blending of the stem guide rof, and the tapering of the guide tips themselves.

image above:: exhaust valve port bowl view. of interest here is the quality of the bowl area, and its transition around the valve guide. you can also see the obvious step that existed underneath the original valve seats (+1mm) which has been blended smooth - this has resulted in opening up the ex valve port diameters by around 2mm.

:: You're a tool....

a few people have asked me specifically what tools did i use for the above work, and so here she is, my friend and yours, the dremel. 37,000 rpm of 'knife through butter' cutting and grinding joy. the key with the dremel and the following bits is TAKE IT SLOW- the cutting pieces can chew straight into the alloy before you know it. 

recently, ive actually been looking at using some burring dental tools available from dental supply places -for dentists, der- they have a massive variety of types and shapes, and are cheaper than dremel parts also.

for more information regarding the types of dremel cutters available, check out:

http://au.dremel.com/html/products/accessories/carving.html

http://au.dremel.com/html/products/accessories/sanding.html

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