wtomlinson

iTrader: (6)

what tip did you use for your dremel? i had a slightly cone shaped bit and it wore down way fast. i got a lot grinded down, enough to even it out and not look retarded, but there's still plenty more to take off.

letsrunem

iTrader: (15)

I used 115 and 117 in this pic but you have to be careful because they cut pretty quick. Then some sanding drums. DO NOT polish it.

wtomlinson

iTrader: (6)

why not polish it?

letsrunem

iTrader: (15)

Polish it if you want the inside to look pretty, but it won't flow any better or make any extra power. The polished surface is "slippery" and causes uneven/inconsistent flow. With the sanded surface, the air that touches the outside is consistently at a lower velocity causing a ball bearing effect- with all the rest of the air flowing smoothly and uniformly. Same goes for ported heads.

wtomlinson

iTrader: (6)

makes sense, in a way. i'm a little lost on the "ball-bearing effect" you're talking about though. could you explain that a little?

letsrunem

iTrader: (15)

I saw a pic on here that illustrated it pretty well but I can't seem to find it. Picture the small layer of air that actually touches the throttle body wall tumbling while the air in the center goes in smoothly. Tough to explain.

DropTopBird

iTrader: (17)

Where did you get those tips and What material are they made out of? I used a carbide burr bit for doing my jeep TB, but it was kind of rough.

letsrunem

iTrader: (15)

This was just a pic from the net but you can get them from Menards, HD, etc I think I've even seen them at Walmart. They're a hardened steel and have no problem cutting aluminum. You just want to make sure you're not spinning them too fast or else the aluminum will heat up and clog the blades.

jimmyblue

iTrader: (11)

I used 3/4" sanding drums (Black & Decker
kit plus extras) in a 1/4" electric die grinder.
My thinking was, the drum will not make a
divot if it (say) kicks back and bounces to
someplace you didn't want to go. They make
a softer cut. Started off with 60 grit for the
main hogging and finished with medium and
fine, then on to hand sanding with 220 and
400 grit.

You'd go through a lot of those little Dremel
joke drums though. The big ones last a lot
longer.

Mask the seating circle with a few layers of
masking tape and that ought to keep you safe.

01ssreda4

iTrader: (96)

i agree, an electric die grinder is the way to go. a dremel is a toy.

MikeGyver

iTrader: (5)

It's the same as a golf ball. A golf ball without dimples will only go half as far (I'm making that part up) as a dimpled one will travel. The air on the dimpled one attaches to the surface and follows the shape of the ball, like a land speed record car, closing behind the ball faster and disturbing the air less than a smooth ball. On a smooth ball, the air detaches from the surface on the rear side, causing turbulence and drag, like a semi trailer.
The dimples keep the air attached by causing it to turn a little and keeping close to the surface, instead of generating vortices as soon as the cross section of the ball begins to diminish.
In an engine, any time the port surface curves away from the air, turbulence will occur, reducing flow. A rough surface helps keep the airflow attached, reducing turbulence and improve its ability to follow the port, or throttle body, wall.
It was even popular for awhile to carve golf ball-like dimples into the small radius of a port. I don't know why that isn't seen anymore.
Another example of a way to keep the airflow attached is vortex generators. These are small pyramid shaped things that you stick on the body of a car to reduce turbulence. For example they would go on the rear edge of the roof on a pickup truck, or the same place on a 1987 Impala, and the rear edge of the trunk on that car. These pyramids cause the air to curve down and follow the body, reducing drag.
On the other subject, I use 1/4" shaft router bits made for cutting wood, in my electric die grinder for carving aluminum. If you get the ones with only two cutting edges, they don't get clogged with aluminum, but they remove aluminum so fast that you can quickly ruin something if you don't practice first.

wtomlinson

iTrader: (6)

well i used the 115 and 117 bits, and that made a world of difference from the grinding tip i used before. i was actually able to see a nice pile of aluminum on my table this time. i didn't do too much, as i was unsure of how deep to go, but i can definitely say it worked a hell of a lot better.

what's the main difference between an electric die grinder and a dremel? just size and speed or what? my dremel spins to 30k and it worked for me.

MikeGyver

iTrader: (5)

It would be like cutting a log with a Sawzall compared to a chainsaw.

BriancWS6

iTrader: (18)

I use a pneumatic die grinder and some decent sized flap wheels for the bulk work, and the little dremel for fine details when I port them.

I use to use the dremel the entire way. Damn those little drums! Lol.

Damian

iTrader: (89)

I used a full sized carbine bit to cut the "lip" in front of the blade out, and the rest was done with sanding rolls using a high speed die grinder. I finished them off with 120 grit, which I don't recommend doing any finer than that.