I was thinking about putting a 13b into my 81 rex. I don't know if this engine will fit on the current mounts. I was wondering if anyone has put a 13b into a 12a engine bay and if I would need to do anything to get it in there like tranny work of something. Any and all help is greatly appreciated.

 

the only thing you need to do is change the sump, and front crossmember, and something about the timing cover! thats about it, im not exactly sure what the sump has to be changed to, maybee the 12A sump, im not sure. PAC here in Syd makes Kits to put the 13B into 12A rx-7s, and they did the work for me.

My 81 now has a 13B EFI 6 port in place of the 12A carb. and thats pretty much what they told me they had to do! all the efi work i have done myself.

The tranny should bolt straight up!

 

The crossmember can stay the same, you do need the oil pan though. The bolt holes in the engine mount plate can be ovalled, or you can get a pre-modified one from Racing Beat or Mazdatrix. (Get it with the GSL-SE oil pan) Given that you need to extend the front of the engine 20mm I would rather go for the modified plate than to gcut that much metal out of the mount plate.

Front cover... if you are going with a carbureted engine you use the 12A/74-78 13B front cover, or if you are going with a fuel injected engine you use the GSL-SE front cover. The difference is in the oil metering pump, carby cars had two outlets and EFI cars had four, and they aren't interchangeable.

 

thanks

 

I've done it 2 weeks ago, i put a gsl-se 13B in my 83 GS. The only things i changed, is the 13B RB headers, i bought the 13B into 12A chassis front engine mount from RB, and the engine bolts right on. There are little minor modifications. You'll need a fuel injecter block off plate that you can order from RB too.

It's all it comes to my mind

Max

 

It depends which 13B you use!!! I put a 4 port 13B in my '81. The engine already had a "front-mount" cover and I just modified the 12A engine mount, mainly by welding extensions to the "ears". I had to modify the oil pan so it would fit in the 12A chassis. I took it off, heated it up with torch, and worked it into shape with a ball pein hammer. The fan was too far forward so I used spacers to back it toward the engine. I repaced the entire intake system with dual SU carbs, and used a RB header.

 

alright sounds good i probably go with the modified oil pan from Race Beat or mazda I think I know what I'm doing know.

 

I'm only new to this but was also considering the same conversion myself. Would someone be able to give me a rough idea on the price of this. Also if anyone out there knows of a cheaper way to get a bit more power out of what i think is a stock 12A could you let me know. Any help would be appreciated.

 

13b in a 12a car isnt possible man, they are lying to you

 

Hate to tell you but it is I was just getting advice on how to do I know more than one person who has done this but I can't get ahold of them so I came here for some help. You can buy a remanufactured 13b specially designed to fit a 12a bay. Sure you might have to do some tranny work and shape the oil pan but nothing comes easy.

 

So n00b question...change the mounts, get a new oil pan, and swap the 13b right in?

-now one guy said to block of the MPFI system? wtf would you do that for? I hear of you guys switching to carbs instead of injectors? why?!????!?!?!? And...another b00b question...a stock 13b is NA correct? Can you put a turbo 13b in there? How much more expensive is a 13b turbo than a 13b NA? what cars (years models) did they come in? And finally...can you make a custom turbo kit for a NA 13b? and is there any reprocussions for compression with boost? I know from my turbo neon experiences...lower compression with boost is good...but whats with the rotaries? is there such a thing as high CR?

 

www.racingbeat.com make a front mount specifically to put a 13B into a 12A chasis. Depending on the year of the 13B, you may need a front cover too. 86+ 13Bs used a "cradle" type mount, where ours use a front mount. The oil pan from an -SE will clear the steering and sub frames and crap, and it should drop in after that.
Block the what?
Cheap power. Stock injector systems and ECUs on the RX-7s arent that great. Carbs will flow better and make more power on a 13B than the stock FI system "tuned" with bolt ons (CAI, exhaust, whatever). They also are a lot cheaper to work with .
84-85 13Bs are all NA. The second gen RX-7s (86-92) have both an NA and turbo version, so both motors are available.
www.corksport.com www.fc3s.org
13Bs came in everything 85 and newer, and the 84 and 85 GSL-SEs.
Sure. Then again, you could make a life size replica of the stay puft marshmallow man in your back yard. It all depends on your budget.
High compression + boost = Trouble.
You idealy want low compression for boost just like with your Neons. "High" compression in a rotary is probably considered 9.7:1. Heres a good link for ya: http://www.mazdatrix.com/faq/rotorwgt.htm

Hope that helps.

~T.J.

 

thanks again!

 

I still say it isnt possible LOL Anyways, read my signature I got a 13b 4 port from a Cosmo. Its a JDM motor I had imported from Japan... The car was orginally a 12A car, but anyways, to make it fit you need 12A front cover, modified or buy Racing beat motor mount, a SE oil pan, and a LOT of beer. 12a tranny will fit a 13b

 

Why would anyone want a 13B....

 

hey r\ternie glad to see a fellow neonite into sevens also i post on the org as flight_of_pain.

see you on both forums

 

you can simply do more with a 13b than a 12a. I have a hell of a time finding parts for my 12a rebuild if I can find a 13b in relatively good condition theres alot more parts readily available. Plus theres the power issue. And the 12a's arn't really an efficient engine they are know to eat the coating on the inside of the block which I hadn't heard of till about 2 weeks ago. If your looking to put out more hp you'd want a 13b.

 

I am so surprised know one has mentioned a key resource that could help you greatly. THE SEARCH BUTTON! It is a wonderful thing! Plus you could always read the sticky on TII into a GSL-SE, at the top of the page. Even if you aren't going turbo, it still goes over the mounting of the engine.

 

I used an rx4 sump to do it, changed over the mounts and ctrossmember, bolted it straight to the gearbox and have since found out why you change to an FC gearbox if you can, FB ones just arnt strong enough, been through 2 in 3 months. Also still running 12a carb with custom intake (gota change that soon, so not enough power)