Fast Freddy from Winnipeg told me that they were same, and any info from him is sketchy at best.

Anyways is this true?

I ask this cause, i recently got a free 12A shortblock that i am in the process of tearing down for inspection, and would like to to a port job at the same time. From the brief searching i did i couldn't find anyone that sells 12A streetport (or bp) templates, so if the irons are the same could i not just use a T2 template?

 

i really hope he was pulling your leg , no way near the same

 

they aren't exactly the same but I thought you could use 12A endplates with 13B housings and center iron?

 

Ok maybe i shoudl rephrase that question...

Are the ports the same (or similar); can a 4 port 13B streetport template work on a 12A?

 

A template will only show you how far to expand the port opening. It wont show you how to smooth the inside, backcut the inside edge by the water jacket, or shape the ramp. You cant port into the oil control ring track, you can't port into the side seal track, you dont want to port too far down and you need a scissor effect on the closing edge. Those are your basic guide lines. Just check out some pictures from people who build good engines and try to make your ports look the same. search for jude ito in nopistons.com
check out the section called engine building and porting

 

I understand that a template will not tell me HOW to port. I just would like a guidline/something to start from, for a decently larger port.

 

Ok, here is your homework:

Porting timing
http://www.yawpower.com/dectech.html
http://www.nopistons.com/forums/inde...pic=43340&st=0

Excellent examples of the art of porting
http://bdc.cyberosity.com/main.php
https://www.rx7club.com/rotary-car-performance-77/pics-blue-tiis-engine-build-new-type-primary-port-489429/

N00b's Guide to Porting
https://www.rx7club.com/rotary-car-performance-77/noobs-guide-porting-56k-beware-619991/?pp=15

Get studing

 

for the purposes of porting, yes

The OP's question was will the porting templates that are used for the 13b/13bt/13brew side irons work as a porting template for the 12a?

for the basis of the outline then yes, however the actual port timing may or may not work well depending upon your intended usage..... are you going turbo? NA? these are the questions you need to ask, and then look for a porting template that is intended for that style of induction.

"names of port style depend upon country you are in"
a streetport / sideport good allaround port for turbo or n/a
halfbridge or full bridge port great for N/A apps, but tricky to tune for turbo, some swear by it others hate it, do your own research in this area.

good luck

kenn

 

Yeesh at some of the answers in this...

Anyway, 12A center irons can be taken a lot larger than the 13B centers in terms of port size. Personally, I just use the same template on all 4 intake ports.

 

I guess i should've mentioned this earlier, but since i got this motor for free i decided this was going to be a "practice" motor, a motor i could start playing around with porting, so if it goes horribly wrong, it's no money outa my pocket.

In fact i don't even have the motor completely apart yet (due to not having a 54mm socket for the flywheel nut), so it's possible the motor is shot anyway.

But i am still going to try my best to make this a healthy running engine of course.

 

and judging from your list of cars, what do ou plan to put it in if you are successful in porting and rebuilding it?

 

S5 plates are lighter and stronger than 12A plates. Mazda accomplished this through creative casting methods.

If I could choose a set of plates as if the coolant seal location and port size/location/timing/bolt pattern issues didn't exist, I'd choose S5 plates over 12A from a strictly strength point of view. Otherwise I'll keep in mind the percieved strength limits of 12A plates and proceed accordingly ie not high amounts of boost etc.

 

You're probly thinking of the Fiero right? Although the idea of putting it in the fiero had crossed my mind, i didn't give it much thought cause i know that would be a ton of work. But hey, it might be worth it since the v6 in it now needs a rebuild.

Actually i hadn't thought of a vehicle to put it in yet, maybe if i find a FB rolling chassis or something.

 

actually, no. my question may not have been worded as i intended. i was simply inquiring if you had plans to buy something (particularly a pre-'85 rotary chassis) to put the 12A in because i didn't see one listed in your signature. that's all.

 

As of right now i don't have any vehicle in mind to drop this motor into, and im not going to worry about that until the engine is nearing completion.

Well i got the motor half apart and found a boat load of carbon, and two broken apex seals (on the rear rotor), and i stopped for the day once i reached the front rotor.