Cylinder Head Work Port and Polish - Page 2
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  1. #21
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    Quote Originally Posted by triumph406 View Post
    61 and still putting in 80 hours a week, your a real success story, just sayin...

    Look for some books by David Vizard, a lot of what applied back when he was tuning Minis would apply now.
    Excellent book this!
    Also if you're interested, "twice lucky" by Stuart Turner.

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    There are some machines that when you purchase them, you get solid models. I think Centroid has a machine designed for head porting like that.

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    Quote Originally Posted by gustafson View Post
    No, the magic is in the very particular knowledge.

    I think personally that the newer fuel injected motors make all this fuss about magic porting really of secondary importance. Obviously good flow is important, but nowadays if you see a lean spot you get rid of it with the computer. If is caused by poor flow it really is unimportant. Back in the day you have only so many jets and such to change, and if you have a poorly shaped port, it is going to be a compromise somewhere.
    I am just shopping for CAD files.
    Good ones.
    That is all.
    Thanks,
    Mark

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    Quote Originally Posted by snowshooze View Post
    I am just shopping for CAD files.
    Good ones.
    That is all.
    You may as well kiss it off and quit bothering everybody because no one is going to either give or sell them to you. This is dumb.

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  7. #25
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    I have a masters in aero but do not have a flow code so I designed the ports for a new BSA head by drawing it in CAD then 3D printing and testing on a flow bench.
    It is not the best shape since it has physical constraints (valve angle, length, chamber shape, carb size, et cetera) but it changed from 75 CFM at 10" for the stock shape to 96 CFM, which is fairly good.
    Unless you have a complete model of the engine with valve opening profiles, tract lengths and shape, thermal effects and much more, you will not come up with an ideal port shape. Gordon Blair at Belfast University has and engine modeling program that is used by race team engine builders.
    A flow bench will not have the resonance of a valve periodically opening and closing (unsteady flow). If you have a pitot probe that fits down the tract you can find where the flow is separating and improvements can be made.
    a65_ports.jpg

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  9. #26
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    Quote Originally Posted by magno_grail View Post
    I have a masters in aero but do not have a flow code so I designed the ports for a new BSA head by drawing it in CAD then 3D printing and testing on a flow bench.
    It is not the best shape since it has physical constraints (valve angle, length, chamber shape, carb size, et cetera) but it changed from 75 CFM at 10" for the stock shape to 96 CFM, which is fairly good.
    Unless you have a complete model of the engine with valve opening profiles, tract lengths and shape, thermal effects and much more, you will not come up with an ideal port shape. Gordon Blair at Belfast University has and engine modeling program that is used by race team engine builders.
    A flow bench will not have the resonance of a valve periodically opening and closing (unsteady flow). If you have a pitot probe that fits down the tract you can find where the flow is separating and improvements can be made.
    a65_ports.jpg
    Just to throw some fuel on the fire.. What is an "Ideal" port shape..

    WHAT is the GOAL? What are we trying to achieve here?

  10. #27
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    Quote Originally Posted by Bobw View Post
    Just to throw some fuel on the fire.. What is an "Ideal" port shape..

    WHAT is the GOAL? What are we trying to achieve here?
    More ponys out for the motor, I guess.
    Make it burn more gas.

    If they have one for sale, they can fill in the boxes.

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    Quote Originally Posted by snowshooze View Post
    More ponys out for the motor, I guess.
    Make it burn more gas.

    If they have one for sale, they can fill in the boxes.
    I guess what I'm asking, just to throw fuel on the fire..

    Are we just looking for PEAK HP.. OR.... are we looking for a big wide power band,
    a ton of torque all throughout. Something that is FUN to drive, and probably faster,
    even with a lower peak HP number.

    Just my thoughts. Just looking for max flow, gets you max HP, but that's it. You're not
    running 6500 rpms ALL the time.. You still have to drive the thing.. You still have to
    pull through to 6500 rpms.

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    Quote Originally Posted by Bobw View Post
    I guess what I'm asking, just to throw fuel on the fire..

    Are we just looking for PEAK HP.. OR.... are we looking for a big wide power band,
    a ton of torque all throughout. Something that is FUN to drive, and probably faster,
    even with a lower peak HP number.

    Just my thoughts. Just looking for max flow, gets you max HP, but that's it. You're not
    running 6500 rpms ALL the time.. You still have to drive the thing.. You still have to
    pull through to 6500 rpms.
    Bobw is a smart guy,precisely why som top cylinder head guys do not brag with flow numbers. They really are not a good metric to judge heads by.


    When I find it I donít need it
    When I need it I canít find it!

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    Every cylinder head is different. I don't see much use for cnc unless you are doing exactly the same model of the exact same brand over and over. If you simply want to maximize flow then you have to relieve all the turns/bends. The skill is to open them as large as possible without grinding through to the adjacent port. Even the pros sometimes have to weld a hole closed because they ground a little too much. Casting cores can drift so it is not an exact cnc type Job. The polishing part is self explanatory.

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    Quote Originally Posted by Bobw View Post
    I guess what I'm asking, just to throw fuel on the fire..

    Are we just looking for PEAK HP.. OR.... are we looking for a big wide power band,
    a ton of torque all throughout. Something that is FUN to drive, and probably faster,
    even with a lower peak HP number.

    Just my thoughts. Just looking for max flow, gets you max HP, but that's it. You're not
    running 6500 rpms ALL the time.. You still have to drive the thing.. You still have to
    pull through to 6500 rpms.
    CNC ported heads from certain manufacturers are very consistent. Engines can be built to a certain "recipe", so to speak, with a predictable outcome especially when dealing with pump gas, E85, methanol, or race gas, combustion chambers get real important.

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    Quote Originally Posted by gustafson View Post
    No, the magic is in the very particular knowledge.

    I think personally that the newer fuel injected motors make all this fuss about magic porting really of secondary importance. Obviously good flow is important, but nowadays if you see a lean spot you get rid of it with the computer. If is caused by poor flow it really is unimportant. Back in the day you have only so many jets and such to change, and if you have a poorly shaped port, it is going to be a compromise somewhere.
    Huh what?! Nobody ports heads to tune a lean spot. WTF does FI have to do with head porting.
    People port heads for one reason, and one reason only: more power. And the fuel delivery method has nothing to do with it in an N/A engine.
    In order to make more power, one needs more air. No way around it.
    In order to achieve stoichiometry in the quest for power, 99.99999% of the time, air will be the limiting factor. Fuel is the easy part.
    Add a power-adder (turbo, blower, supercharger), and that can skew the equation. And, FI can help with the tuning.
    But said tuning is needed because: more air. Just like modified ports can achieve.

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  19. #33
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    Quote Originally Posted by Superbowl View Post
    Every cylinder head is different. I don't see much use for cnc unless you are doing exactly the same model of the exact same brand over and over. If you simply want to maximize flow then you have to relieve all the turns/bends. The skill is to open them as large as possible without grinding through to the adjacent port. Even the pros sometimes have to weld a hole closed because they ground a little too much. Casting cores can drift so it is not an exact cnc type Job. The polishing part is self explanatory.
    Places like AFR and Brodix have thier own casting designs that favor CNC porting with thicker castings along with, in some cases, relocated valves.

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    Quote Originally Posted by standardparts View Post
    Places like AFR and Brodix have thier own casting designs that favor CNC porting with thicker castings along with, in some cases, relocated valves.
    I don't give a damn.
    I am just trying to buy models.
    They can tell me what they have for sale.

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    Quote Originally Posted by snowshooze View Post
    They can tell me what they have for sale.
    They have heads for sale. So buy one and scan it.

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    May help to know if we're looking for heads for a BBC, LS, Miata, etc.

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    Quote Originally Posted by Cole2534 View Post
    May help to know if we're looking for heads for a BBC, LS, Miata, etc.
    May help if I could find files.
    That is all I want.

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    Iíve got files for these
    Don


    Sent from my iPhone using Tapatalk Pro

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  27. #39
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    Quote Originally Posted by D Nelson View Post
    I’ve got files for these
    Don


    Sent from my iPhone using Tapatalk Pro
    Cool.
    What are they, and is there any sales for them?

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    Honda grom intake manifolds and the 125 cc pit bikes
    Don


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