i have a 6 port 13b out of a 85 gsl se i think.. i was wondering what i would need to do to convert it to a 4 port.. and then drop it into my SA

 

You need to pick up a junk 12A.

Replace your irons (end/center plates) with the 12A units and you are done.

Port it, big.

 

well i have a 12a in the car right now.. i was only gonna street port it.. and then turbo it later on

 

Well, you have everything you need then.............................................. ..

 

yeah you have everything you need to do the conversion. you need to make sure of the year of the 13b. it needs to be a 85 or older because of the coolant seals.

 

okay so a couple of questions then.. first how do i know for sure of the age of the 13b.. is there a date code on it somewhere or how do i know its from a 85 or 84? and second.. do i need a new header for the 13b.. i have a 12a RB header.. so if i change the housings over to the 12a housings can i still use it or do i have to get one for a 13b?

 

and one more question.. can i still use my flywheel and clutch?

 

Yes.

 

yes you need a 13b header. i cant remember which way it goes but the changed the the location of where the coolant seal land is. one has it cast into the housing and the other has it cast into the iron.

 

Just look into the exhaust ports.
If its an SE 13B,youll see right into the engine where the rotors are,no obstructions.
If its a 2nd gen 13B(86-92) then the exhaust ports will have some sheetmetal exhaust splitters inside the holes,along the sides.

 

If you have only 2 fuel injectors its a 84 or 85 13B from a GSL-SE. If there is 4 its a 86 or newer. All 84 and 85 13B's are compatible with your 12A housings. Dont be cheap make sure to get the housings lapped before you reassemble. If you ever see a book called How to modify your RX-7 on ebay buy it youll benifit a lot from the info. The books out of print so your only chance is ebay pretty much. good luck ,custom13B

 

how and where can i get them lapped? and how much does that usually run? and i will have to look at the ports tomorrow.. its in the hatch of my SA... and its dark outside.. not to mention cold..

 

Mazdatrix or racing beat lapps housings. Your closer to them than me Im in NY. Check around though as I thought a place in Penn also lapped housing..pineapple racing maybe? all the places I mentioned have web sites with pricing. Get yerself a copy of How to modify your RX-7 will answer many engine building questions for you. Check ebay for it. The Factory manual is good but I prefer the other book better pics and explanations. Get a flashlight and go check the motor..shesh its not snowing yet. Check under the manifold for the injectors is the easiest way. Ttyl,custom13B

 

okay here are some pics of the 13b the exhaust ports and the top of the engine .. it says 13b on the rotor housing..