Peripheral Port..
 

Has anyone built their own peipheral port housings? How did they go about this? Also what did you use to fill the water jacket around the port? And also fill the old intake ports? Any help on this would be great? Also info on the engine internals you went to with the port job would be great. I would like to build a 12a peripheral port motor with a weber. For my 83' LE. Or if anyone sells the housings for less than racingbeat does that would be cool to. I'm not out to buy right now just trying to plan this out for the winter.

Oh I already know about the noise, low gas milage, and the low power at low rpm's. :)

No one huh?

The racing beat ones are about the cheapest there are. I would think you would like a bridge port better than a pp. Especialy if you want something that will be easier to tune. You can make almost as much pwr but get some more dirvavbility out of it. Plus its easier to just buy a manifold rather than always having to make your own and stuff. plus tuning is expensive, especialy when a lot of it has to be done on the dyno.

CJG

Anyone know how the two compare when it comes to engine life?

lifewise the PP will wear out sooner due to it revving higher all the time.

thats assuming you only go the standard type bridgeport, if you extend the bridges past the water seals, they are likely to leak, requiring rebuild.

DEVCON I believe they use to fill up the water galleries when going PP, it is on the racing beat website somewhere I am pretty sure.

Ok well bridgeport is starting to look better. Less costly and I could probaly do it my self.

Devcon it is... But anyway, just wondering about this: would it be possible to PP the housings yourself, or should this really be done by a shop??? I mean: getting them from racing beat is hardly an option overhere (shipping costs are HUGE) so I'd like to know if it would be possible to do the PP myself. Not sure if I will, don't need to right now either, just curious...

I got 2
 

HI,,
I bought recently 2 mazda RX7, one 1981 and the other 1985.
And the guy give a lots of parts including to PP ports already made. I never test it and the guy who made it was a machinist. If any one is interessting I can solde depend on what price you give. I don't want to make a lots of money with it, buy I would not give it away anyway. Any serious offer will be consider. Send me a private email (ve2cvx@cgocable.ca) to ask for picture of the parts.

Here's a site that can probably help you some :http://personal.riverusers.com/~yawpower/

www.k2rd.com is doing them on an experimental basis

mike

So has anyone made their own birdgeport? How much harder is it than a street port?

I made my own bridgeport. THEY are MUCH more diffcult then streetport because you have to start the new port and CAREFULLY cut it out. You need a fairly narrow dye grinder bit and very steady hands if you want it to be good. It probably comes easier to those who make them often, but I don't. Then remember, you need to do the operation 4 times. Then if you plan to relieve the rotor housing, thats 4 more cuts. So the answer its rather time consuming and worth it to do it good and slow.

After doing a bridgeport, regular streetports are cake.

Now if you had a good mechine shop and all the nessessary tooling, a perpheral port wouldn't be all that impossible or diffcult, but not everyone here has access to one. Besides that, you may not know exactly what shape to make your PPort or were to position and orient the port angle, etc.

I'd say I have a steady hand I do a fair amount of welding mostly gas. Anyways you say have to relive the rotor housings explaine? Or you could pm or email me some tips if you could that would be great!

relieving the rotor housings just means that the area that is cut into the rotor housing slightly(in the region of the bridgeport) to allow the new port created by bridgeporting is flowing up to its ablity. The cut goes shy of the water jacket, I have mine 1mm thick so the water jacket is well sealed yet. Which also requires carbon seals since 2-piece steel seals will fall out of place, not to mention the chatter created at high rpm in steel ones.

What other internal mods need to be done to a 12a bridge? I know that it is recommended to upgrade to lightened rotars, carbon seals, clearencing, and stationary gears. Anything else?

I have all stock internals for a '85 12a except carbon seals, 93+corner seals springs, HP oil regulator. Outside mods light flywheel, underdrive pulley<-mainly to keep the water pump from cavitating at high rpm. I don't go above 8500rpm though so harden stationaries and lock-pined rotor gears are not required, but if you plan on keeping it at 8500+rpm for long periods, you do need them or you'll reck your stationary gears. Also balancing the whole rotating assembly if you plan long periods of 7500rpm+.

I would recommend a 3window bearing for the rear stationary gear though to keep oil pressure high at sustained high rpm. And a GSL-SE oil pump because of the larger volume it can provide.

I can't wait. I'm hoping to have my project car sometime around christmas. It might take me a year or two to finish it though--possibly more. I'll need to finish school and get a real job before I can afford to do most of what I plan.