Casting Flaws

[number5]

I found some casting flaws so I fixed them.

[number5]

exhaust before shine job

[number5]

more shine

[number5]

from outside

[wilkin250r]

Looks good, what kind of tools are you using?

Are you planning on porting it yourself down the road, or just cleaning it up?

[number5]

Thats not ported?

[Rollscanardly]

"ported" refers to changing the port timing to make the engine perform better at a certain rpm what you see here is correcting minor casting flaws so the engine "flows" more smoothly


Hunter

[number5]

Guess I did both. I went a little further with the exhaust. Instead of doing what most people do and just change the opening I went all the way back with it. What ever I took out up front followed all the way back in a straight line. This took many hours of grinding. Doesnt seem like the exhaust should go into a convergent design before it goes into the pipe.

[wilkin250r]

Obviously you can't make the exhaust pipe the same exact size and shape as the exhaust ports in the cylinder walls.

The best scenario is a smooth transition all the way to the exhaust pipe, no sharp corners or bends, and the final opening is the exact same size as the exhaust flange so there is no "step" to cause turbulence.

It doesn't look like you changed the shape and size of the actual port windows, however, which is what a professional port job would do. By changing the windows, you would be changing the power delivery characteristics.

But keep us updated on the gains you see from your clean-up. It should give you a few horses.

[number5]

I took alot out of the exhaust. I will show pics of stock cylinder tonight so you can see the diference. Im almost done with break in. Low end seems real nice compared to my bigbore more twichy though. My 310 was smooth. This power band hits hard. Im thinking its from the port job. I dont think I want to raise the exhaust ports anymore.

[number5]

here you go.

[number5]

from top

[number5]

You can see the after pics that I went past the transfers not to much but went straight back with them. Done with break in. Low end is close to stock. I notice midrange is a little sputter like. Seems like its ported for top end. As soon as it gets past that it reminds me of my banshee. Not what I really wanted. I dont want to raise the compression because Im at 180 now. Oh well. My next cylinder I will not raise the exhaust port and just widend it. And only a little on the intake.