Thanks to DivinDriver for the link. Looks like a great read. In the parent directory there are some FSM's too. Excellent resource!

 

Found some info that might help

Racing Beat says on the sheet that goes out with the template

drill holes at 15º angle and chain them to make the bridge

cut the housings 1/4" extra from the top and bottom of the bridge

5/32" into the rotor housing chrome surface

 

Thanks for that I always wondered why the bridge on the housing was longer than teh bridge on the iron.

I did some port sketching last night. Not going to bother uploading the pictures again, but here is the direct link:

https://www.rx7club.com/showpost.php...postcount=2833

 

That's Sgt Fox's manuals archive, mentioned in the FAQ. Credit to him for all that work. I just happened to remember the Downing book was there, and talked about bridge ports, s'all.

 

So I got these templates here. First is a little smaller than the next.


As you can see, the seal is still intact.

But as for this one:



Zuh? I wonder how people got around this? What do you do with the seal in this situation?

 

I like the 2nd one, because it leaves more support for the corner seal, but I fear it may move the powerband higher than needed. The upper port looks healthy.

Also, does it seem like the top port closes later than the bottom?

 

Lay the larger template over the smaller one, then lay each one over an iron. The first one looks about the size that I used on my 1/2bp.

 

Alright, hold on.

 

Here ya go. Big over small over stock.

 

The big bridge looks to have the bridge open before the port, where as the smaller port seems to open the port and bridge at the same time.

EDIT: Open earlier as the rotor tip, not a straight line. Also I know the big bridge works and has been used before, but the whole coolant thing has me mystified.

 

The small one is for a bridgeport that retains the whole coolant seal

the other looks more for a Jport....

here, Ive been working with the small one

I started today. I gave it about 4 hours of work
No work on the bowl or manifold side port ... yet

Im using a dremmel and a small carbide bit. Its all I was able to find




ok, here we go


and this is as far as I was able to go today

 

Ah, one question. I see the stock port, and the inside, do I also grind on the inside or do I just "flare" out from the stock port? MSPaint in a second..

 

So I can just port it like this? Sorry if I am asking a lot of questions, or really stupid questions. I just want to make sure I don't hit any water passages or end up making a hole.

Oh, and thats not a j bridge... I will show you a J-bridge

 

Mmmm... J port....

Thats a nice porting job there! I guess I am making it out harder than it is?

 

My limited english skills are not letting me undestand what you are trying to tell me...

 

The red being if I lay the dremel down at an angle to the bottom of the stock port, to the top of the bridge port boundary.

 

My best suggestion is to read through the Engine Building and Porting section over at NoPistons.com. They have a group of very serious and knowledgeable builders over there that make most of us look like first graders. I read through that entire sub-forum before I even bought porting tools, templates or a rebuild kit.

 

+1

I read the whole thing twice, and I still cant understand how to modify the bowl properly.

I dont have the tools to grind at an angle, thats a problem too