My first streetport in progress

[Ender]

First off, I got two junked front irons to practice on, so all these pictures in this post are on a practice iron. I'm using the Racing Beat streetport template to at least start out with, I may make a copy then modify the copy, I would probably only do so for the secondaries.

I'm looking for pointers and discussion, and I have a few questions to get things rolling.

Template over the primary then secondary ports:


Dyed:


Scribed:


Rough cut:


Here's a comparison for the size of my grinding bit, which I think is too big for some spots.... I have two carbide cutting bits, the smaller one is the one I used for this work and works pretty well (it is also smaller than this grinding bit).

[Ender]

Questions:

-I cut maybe .5mm past the outer edge near the opening edge, it happened when I was blending the stock port into where the template mark ended (template isn't as long as the stock secondary port). Is that a problem? Could I actually extend it out that much the whole way? Would I want to? That is where the side seal/corner seals ride, right?

I know, I should get my e-shaft and a rotor out there to check things out that way. I probably will before too long. I won't be able to do much else today though.

-Should I cut deeper at the closing edge? I only angled the opening to the template line. I've seen some ports go very deep there, and from what I've read I don't want to really do that, BUT I suspect I may benefit from ending the slope (meeting the stock opening) about 5mm lower.

-I also want to know if I should cut the template just to the line or cut the line as well.

I know I can also cut a little into the control ring area, but I would prefer not to do that with this motor. Although I guess if I cut the template out like that then that a little control ring surface would be removed...

[classicauto]

1: You could go out a little further by the looks of it, but you'd need to mock a rotor/shaft up and spin it just to make sure the side seal and corner seals are supported because yes, thats where they ride.

2: I don't understand this question. Are you talking about closing the port later, or changing the angle of the bowl at the closing edge?

3: Thats up to you and your plans for the engine. I'd go until the port is flush with the template 2D wise.

4: Again depends on your purpose for the engine. If the template laspes into the oil control ring area, I personally wouldn't go there on a street engine, but some say you can without many negatives (which is cutting into the first edge slightly) but I wouldn't.

looks pretty good though. Bowl and backcutting also seem decent!

[Ender]

Originally Posted by classicauto

1: You could go out a little further by the looks of it, but you'd need to mock a rotor/shaft up and spin it just to make sure the side seal and corner seals are supported because yes, thats where they ride.

Will do.

Originally Posted by classicauto

2: I don't understand this question. Are you talking about closing the port later, or changing the angle of the bowl at the closing edge?

I mean cutting down (if the iron is laid flat on a bench). However cutting down more will necessitate changing the angle of the bowl at the closing edge. I want to know what ought to be ideal. I will state my intentions with the motor soon, as I now realize that's important to this discussion.

Originally Posted by classicauto

3: Thats up to you and your plans for the engine. I'd go until the port is flush with the template 2D wise.

I have been doing that. There's a thin scribe mark on the template, and you can still see it on the template. I'm asking if I should cut off the tiny bit of metal that makes up that scribe mark all around the port outline on the template.

Originally Posted by classicauto

4: Again depends on your purpose for the engine. If the template laspes into the oil control ring area, I personally wouldn't go there on a street engine, but some say you can without many negatives (which is cutting into the first edge slightly) but I wouldn't.

looks pretty good though. Bowl and backcutting also seem decent!

Yeah, I'd prefer to leave the control ring area alone. This is intended to be a mild streetport with the potential to make 300+hp to the wheels later on. I'm going to run the stock turbo for a while, probably more than a year after the motor is installed, but once I have the means I will want to upgrade my turbo (and probably go standalone) and head for the mid 300's. I want it to be efficient, as economical as possible with regard to fuel for commuting, and make good power. I have all new seals/gaskets and good quality used housings, irons, and I think my rotors and e-shaft are in good shape. I'd like to have the rotors trimmed/bevelled/port phasing (there are a number of names for it I guess), but I doubt I'll get to that point. I will be running the stock ECU except for having the Rtek 1.7 chip (so I also have 720cc secondaries), I already have an SAFC-II set up running the throttle off the boost signal. I'm working on scrounging up the money for a zeitronix wideband, but idk when that will happen...