Porting pics and tricks

Stump Shot

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Is the paper marked and cut to a degree wheel setting- or a measurement decided from the squish band after degree wheel use?

Yes it's cut to the thousandth of an inch from the squish band to the new opening of the port, which when done will get it to the correct setting in degrees as checked by the degree wheel.
 

Stump Shot

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It's extremely hard to see what is going on in the back of the transfer, however with the aid of an adjustable mirror it can be plain to see.
The round rough diamond can be used again to reach into the back and relieve any stair stepping so as we are left with a nice radius for the incoming charge to make the turn nicely.
IMG_20230219_200529220_HDR.jpg

The three different cutters set up on the 90° tools used.
IMG_20230219_204400473.jpg
 

Stump Shot

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Onto the exhaust port.
This particular cylinder has the height already optimized just from the machining alone, so we're just going to widen it to 65% of the width of the diameter of the bore straight across. Some may go a little less or more this just happens to be where I like to make them. Again a gauge is made so I have a permanent tool to grab quickly and accurately to check with.
IMG_20230219_205040540.jpg
 

Stump Shot

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I like to rough in with 1/4" tooling starting with an aluma cut bit and working my way down to 1/8" tools with reduced diameters to get the corners tight and the finish finer as I go.
I also like to leave a good arch in the roof for the rings to get by .

IMG_20230219_204521753_MP.jpg IMG_20230219_204309456.jpg
 

Stump Shot

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Keep working my way down once the size and shape are made by sanding and polishing to a reasonable level, I don't get them like mirrors as I feel it unwarranted and unnecessary. However each finer step a straighter more nicely made port shape is made.
Notice that I took more off of one side than the other as this particular port comes down at an angle. So it helps to try and straighten it back out some in our port work.
IMG_20230220_211409422_HDR.jpg
 

Stump Shot

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The intake is left alone the best it can be with the taking out of any imperfections and the manifold matched to the port. If we do have to take some off the bottom, it's usually pertinent to replace it with epoxy on the roof so we don't loose the pull on the carburetor and venturi effect so our motor has enough fuel torun properly.
IMG_20230220_211433474_HDR.jpg
 

Stump Shot

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After all these are work saws and no more air can be brought through than what the carburetor can deliver. Now if that carburetor happens to be larger in diameter this is a different story and now a little increase in manifold and intake tract can be warranted.
IMG_20230222_152231863.jpg
 

scarr

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Chamfering ports? Often people try to use a 90deg for that. I find it easier to use a narrow straight handpiece and a 3/8 fine ball diamond. Maybe a 1/4” for really tight corners on upper transfers.
 

Stump Shot

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Chamfering ports? Often people try to use a 90deg for that. I find it easier to use a narrow straight handpiece and a 3/8 fine ball diamond. Maybe a 1/4” for really tight corners on upper transfers.
With the addition of the little 90 degree I got from you I now use both wherever it's easiest, where I used to use just the straight piece all the time. :)
 

Stump Shot

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Forgot to mention the one thing done just prior to washing is a quick go over with a 3M type whirly bob a mathingy to make sure everything is good and smooth like butter. IMG_20230223_213118410_HDR.jpg IMG_20230223_221551199_HDR.jpg
 

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Norm

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It's extremely hard to see what is going on in the back of the transfer, however with the aid of an adjustable mirror it can be plain to see.
The round rough diamond can be used again to reach into the back and relieve any stair stepping so as we are left with a nice radius for the incoming charge to make the turn nicely.
View attachment 1459

The three different cutters set up on the 90° tools used.
View attachment 1460
Just like the dentist:)
 
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