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Fry Rice Specialist
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Discussion Starter · #1 ·
is it worth the effort to smooth out the casting flash in the intake and exhaust port? basically just take a dremel tool with abrasive wheels to grind it a little bit smoother.
 

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Baby Huey
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smooth the exhaust all you want but dont "smooth the intake", you need those bumps to create some turbulance in the intake stream to help mix with fuel.
 

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Fry Rice Specialist
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Discussion Starter · #4 ·
it's not the bump that i want to clean up, but when you use your finger go through it, it feels like 400 grit sand paper on the port. i want to smooth it to about 1000 grit feel.

is that still a no no or it's a great idea?
 

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Baby Huey
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Casper said:
it's not the bump that i want to clean up, but when you use your finger go through it, it feels like 400 grit sand paper on the port. i want to smooth it to about 1000 grit feel.

is that still a no no or it's a great idea?
I dont think i would touch it.
 

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Fry Rice Specialist
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Discussion Starter · #6 ·
so just go ahead with the exhaust port smooth it to mirror finish but just leave the intake port alone and i'll be good to go right?
 

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i dont see that you would gain much from just polishing but it wouldnt hurt since there are no chances of losing anything
 

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Fry Rice Specialist
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Discussion Starter · #9 ·
the reason i want to do this because the engine still on the stand and i'm running out of stuff to do it right now.

if it let me gain even 1/2 hp i'll still do it. maybe it will inscrease throttle response too?
 

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Super Moderator
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Don't smooth the intake ports. You will actually lose power from doing that. I forget exactly what the rough surface does, but I do remember being told that smoothing it out is not helpful, and that the roughness does serve a purpose.

Mike
 

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I know for carbureted engines you shouldn’t do a mirror finish on the intake side because the rough walls of the port help promote the gas to turn from a liquid to a gas. And if you polished them the gas would still remain a gas form and drip down the intake at random. That would mostly happens at low rpm and idle. But on injected engines the fuel enters the intake much closer to the combustion chamber and the injector its self for the most part turns the liquid gas to a gas form.

Soooo, polishing the intake on an injected motor should be fine. I personally wouldn’t go to a mirror finish on the intake but I would def smooth it out. And you can go all out on the exhaust port.
 

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warmaster259 said:
smooth the exhaust all you want but dont "smooth the intake", you need those bumps to create some turbulance in the intake stream to help mix with fuel.

True on carb or TBI engines, however in these motors the injector sprays the fuel directly onto the closed intake valve just before it opens. You get better vaporization that way.

IMHO don't waste your time Casper, the exhaust port needs work in the bowl and the intake port needs help on the roof about halfway down and bowl work. If you are careful you could fix the stepped edges in the chamber near the valve seats, but if you screw up the valve seat, its gonna cost some money at the machine shop to fix. Polishing smooth will help keep the carbon buildup down, but thats about it.
 

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Fry Rice Specialist
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Discussion Starter · #14 ·
thanks for the advice guy. seeing how those ports bend into the head and don't want to risk the shaving down into the combustion chamber, i'm gonna scrap this idea for now.

original plan is put the grinder in and put a vacumm at the side to suck out, but if the valve is closing then all the turbulance is just gonna kick those shavings into the combustion area.

so not wanting to unbolts the heads i'm just gonna leave it as is.
 
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