Fd3BOOST

That sucks man. I am sorry you broke the jacket. Does that come out of your pocket?

I see you scratched the face of the intermediate housing also. Make sure you block sand that with some 400 grit or your friend might have a smokey engine.

Keep working on it, your getting there.

Dale

I thought it would be clearer since we merged the "Secondary Porting Idea" and main porting thread to Quote from the post I was referring to. P'cola FD's idea for secondary ports.



I am not a fluid dynamics expert, just a hobbiest. I think this idea has merit. I finally found the information I knew I had read a while ago on porting:



From: http://www.babcox.com/editorial/ar/eb120121.htm

"On late-model Chevy Vortec heads, you don’t want to change the shape of the port much. The best advice here is to clean up and equalize the ports so they have the same height and width. On small-block heads, there’s a large pocket right below the rocker arm stud in the roof of the port. This should be filled in with epoxy to improve airflow. Doing that will give you an extra 15 cfm."



Is the pocket in the port on the long side radius? If so it could help quite a bit. Remember an engine is a pulsed system so the air is stopping and starting in addition to the wave pulses reflecting through the intake tract so a flow bench may not show an accurate picture. I would think a change like this would show more improvement than the flow bench would indicate. I would love to see more experimetation like this. Let us know how it turns out.

Judge Ito

Piston engine porting could not be compared to rotary engine porting. Two totally different types of engine. a rotary engine has alot of power to gain from changing the port shape. The factory port shape on a rotary engine has everything to do with intake timing. On a piston engine port shape has nothing to do with intake timing(On a piston engine, intake timing is determined by the camshaft). Basically when a rotary engine is ported or bridgeported, you are basically adding a camshaft to a rotary engine. Depending on the type of port your doing to a rotary engine will determine the size of the camshaft your adding to a rotary(even though a rotary engine does not use a camshaft.. porting and changing the port shape is equal to a camshaft) When you change the port shape of a rotary engine, your advancing the intake opening and delaying the port closing .. Similar to a camshaft on a piston engine.

P'cola FD

So you're saying that on the primaries, I should make the angle of the inside of the closing portion of the port steeper? I was kinda scared to do that, with the whole front housing incident. I also figured that the more gradual angle would create less turbulence. But you know a lot more than me, so I'll take your word on it. Could you go into a little more detail as to what I need to do to the secondaries?

Judge Ito

Ill try to explaine so you could understand me better. I know is hard trying to make a perfect interpertation of what I'm writting. The primary ports are looking nice. Just take the upper edge and just that edge slightly angle it up, allowing for less turbulence and better flow. Your not going to deeply port that upper edge, your going to lightly angle that edge, not to deep where you could port into the water jacket, but just enough to allow a better flow.

Dale

Judge Ito



I am somewhat familiar with the Wankel Rotary engine. Maybe I am mistaken, but this is internal to the port and not the face of the port. So we are no affecting the port timing only the flow characteristics before it gets to the port face. Air internal to the port is seeing pulsed flow similar to a piston engine. The example I linked to was talking about an internal port characteristic of the Chevy Vortec head that I thought was similar to this void and hump P'Cola Fd was talking about. Hope this clears things up.



Dale

Dragon

It's actually much diffrent as the port is only closes for a very short period of time compared to a piston engine that has to go threw it's exaust stroke etc.. the valve only opens one time per two revolutions of the crank shaft... the rotary engine opens the port 3 times for a much longer duration in two rotations of the e-shaft so there is a more constant flow of air and very little close time..

R1TT

For the beginner porters out there are you guys using templates? if so which ones, I see that Mazda trix, atkins and racing beat offer these templates, Im interested in the street port template,

which one for the guys that are using them, are bigger? cause Im contimplating on getting a set

I've read that using these templates they have less agressive port? Is that correct?

I know for you hardcore rotary engine builders you probably have your own designs

also earlier in the thread Judge Ito says that he may be making some, If so I'd definitely be interested.

So Judge is it true? also exaust port pic's please, I wanna see them, thanks

JimmyJimboJet

dave, what were all the different types of bits you used? like size and everything

JLB

Here are some of my favorite porting tools. The staple is a standard 1/4" die grinder and assorted 1/4" carbide burrs. When starting out I like to use the straight sided bits to go around the opening of the port to get close to the scribed lines. Then I switch to the rounded ones since most of the port is concave and a squared end bit would leave awful grooves. On the left in the pic is my favorite die grinder. It is a 1/8" pencil style that hits over 60,000 rpms. It does not have much torque, but it removes metal faster than you'd expect. It gives you complete control - a big die grinder can get away from you easily. The other great thing is it is small enough to go deep into a port without having to use a really long shanked bit. The longer then shank is the more pronounced the chatter is at the bit.



Jason