How-To Intake Manifold Port and Polish
How-To Intake Manifold Port and Polish
Hey im looking to port and polish my own intake manifold. Can anyone help me with this, I have never done this before. Thanks!
yeh we had a thread a while back trying to get a step by step how too. but apparently its so easy it doesn't need a how too 
hopefully someone will do one, im interested in this also
hopefully someone will do one, im interested in this also
Well, since I've not looked at both the head and the IM ports I can't say this for sure...but if the IM is ported (a good amount now) and the head's ports don't match, that'll create a bottle-neck. But now, I've P&P'd my own IM for my Civic. The stg II head on it was professionally P&P and I just gasket-matched the IM so it'd about the same so the head. Same method with the TB... No sense getting a 70mm TB on a 58mm IM opening.
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Joined: Jul 2003
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From: Jackson, CA (NorCal, Sacramento)
quick how to...
take IM off engine.
place gasket onto manifold with some bolts through the holes to hold it in place where it needs to be.
take a sharpie and color in all the metal that protrudes past the gasket at each runner.
remove gasket.
now spend the next couple days with your grinder (dremel or something like that) taking out all the metal that was colored. no need to go more than an inch or so into the runners.
whatever you use, make sure it only spins at no more than about 12000 rpm.
make sure to use a non-ferrous aluminum burr.
WD-40 will be your friend as it will keep your burr from gumming up.
rinse manifold out with water or air or both when done to clear any shavings out.
there you go, enjoy.
take IM off engine.
place gasket onto manifold with some bolts through the holes to hold it in place where it needs to be.
take a sharpie and color in all the metal that protrudes past the gasket at each runner.
remove gasket.
now spend the next couple days with your grinder (dremel or something like that) taking out all the metal that was colored. no need to go more than an inch or so into the runners.
whatever you use, make sure it only spins at no more than about 12000 rpm.
make sure to use a non-ferrous aluminum burr.
WD-40 will be your friend as it will keep your burr from gumming up.
rinse manifold out with water or air or both when done to clear any shavings out.
there you go, enjoy.
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Joined: Feb 2007
Posts: 72
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From: Kunsan AB, Republic of Korea
Laundry bluing works too for marking the intake...wipe some on before you mate up the gasket and then take something sharp with a fine point to LIGHTLY scratch the shape of the gasket opening. You can usually do the same thing on the other end of the intake matching the opening to the TB gasket, but it depends on how much material there is...you don't want to make things too thin-walled. I agree with gasket matching the head too if you can...follow the same procedure. I'd recommend completely stripping the head down before doing this though so nothing gets stuck on top of the valves. While you're at it, it's often a good idea to polish the ehaust runners...there isn't as much need to gasket match the exhaust side since the piston is physically pushing the exhaust gasses out instead of sucking them in, but it certainly wouldn't hurt...but then you'd probably want to gasket match your exhaust manifold too. When polishing the exhaust side, work your way down to a very find grit to make it nice and smooth...you could even do the same in the combustion chamber too if you feel froggy...just don't go overboard.
A good way to get some practice first is to go to a junk yard and pick up an intake or head or anything you can get that's as cheap as possible...tell them you don't care what it's off of or what condition it's in, you just want the cheapest aluminum part you can get. Practice on it until you are confident enough to start grinding away on the parts you'll actually be using.
A good way to get some practice first is to go to a junk yard and pick up an intake or head or anything you can get that's as cheap as possible...tell them you don't care what it's off of or what condition it's in, you just want the cheapest aluminum part you can get. Practice on it until you are confident enough to start grinding away on the parts you'll actually be using.
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ya ill post some pics tomorrow, Today i cleaned the whole intake out with intake/TB cleaner. Then a ground all of the flash off of the outside of the IM, so now its nice and clean outside. I started doing the actual porting today. Placed a new gasket on it and bolted it into place. Then inked the area that needs to be removed. I then started carefully removing the extra metal that was inked. Ive gotten about half of one opening done 
Im learning how to make a smooth curve without having bumps in it. How exact does the interior diameter have to be ? I know some turbulence in the air is good but what should i be looking for in my porting here ?
Im learning how to make a smooth curve without having bumps in it. How exact does the interior diameter have to be ? I know some turbulence in the air is good but what should i be looking for in my porting here ?
Just keep what you're doing... Take away that extra material, taper it to the inside, and don't polish it! Keep it rough to help the atomization of the air/fuel mixture into the cc.
how rough is rough ? I mean im not going to go in there with a polishing wheel and make it look like a mirror but is the surface the grinding bit leaves behind the right texture.