porting on the intake side. i am trying to get an idea of how far you can port before the side seal becomes and issue. i am at .450 inch from the coolent jacket on the intake. i would like to extend it as far as possible without bridgeing. i am using a caliper to measure.

 

heres what i do...

put the rotor housing on the plate. then get a spare apex seal and corner seal and put them together as if they were in a rotor. then slide them across the rotor housing as if it was in the rotor. then mark the area you would like to port to that still leaves enough support for the corner seal.

some people will take it futher than others. i like to leave at least half of the corner seal supported. for street driven motors anyway...

there are other ways to do it. but this is an idea i came up with one night when i was doing some experimental porting.

 

Quite a few doing their porting this way

 

My port leaves about 3/4 of the corner seal hanging over, it's a rubber grommet eater

 

half is pretty close, i want to max it out but want to keep the side seal from dropping off. i came up with .390 from the coolent seal jacket before you are in path with the side seal. which is about half with corner seal. thanks all for the info as well. i just want to extend the port as far as possble while keeping all the seals happy.

 

You've got 11.43mm of material, I never go less than 11mm flat.

Not worth pushing it, having to tear down a perfectly good engine b/c it's eating side seals sucks. I know this b/c I used a "reputable" builder's porting templates many years ago..... and promptly threw them in the trash

 

You're not talking about Judge Ito, are you?

I've had great results with his, as long as I put a nice bevel on it.

 

beveling the closing edge of the port is key or it will eat the tips of side seals on large street ports.

 

i've got a set of irons that someone has ported to about 10-10,2mm, leaving the tip unsupported.. is it possible to save these by beveling the closing edge? is it worth doing this?

 

Scissor and bevel is the key. I see many including "gurus" who put too rounded a corner on the upper outside port edge so the tip of the horizontal side seal hits its tip before the reast of the seal is back on the plate.

10mm is cutting it sooo close. You should have a little less than .5mm of the vertical side seal tip still on the plate, but you should physically verify this.

I do 10.5mm and have a template I have physically verified the seals tracks with.

The little bit in red where you really have to watch it.

 

i figured beveling the edge would be fairly standard. with my measurements i came up with 9.90mm (.390 in ) before the seal is off the edge. i may go 10.25mm (.4035 in) on my engine and test it out. from what i have gathered through some reading is that the power is in extending the port as far as possible.

 

Haha don't test t out on my motor steve I think the normal streetport would be fine is this for your normal red fd or the other one you just got??

 

this is for my red fd. i want to push it as far as i can. .390 is the max i have measured before the seal will basicly be out. i may try out .400 on the secondarys and .450 on my primarys for good midrange. ill post pics once i am done. got to experiment...