13B in first Gen?
 

Hey, Im pretty new to the whole rotary engine thing. I just bought an 81 rx7 no to long ago. And the old 12a that is in it is having issues. Im wondering if there is any huge difference between the 12A and 13b engines, as far as how they bolt in the car. Does anyone know if they can bolt in as a replacement? Or is there to muchof a difference? I know that the later years int he first gens offered the 13b out of the factory.

Do a search for 13B swaps. It's been covered to death and is fairly straightforward from what I understand. But first make sure your 12A truly isn't any good. What kind of issues is it having? It may be something as simple as a tune-up, or adjusting the carb properly. The 12A is a pretty robust little engine. Do yourself a favour and save some bucks. Try to sort out the 12A before jumping into an engine swap.

Welcome to the forum. +1 on orion. Make sure the 12A is actually toast before assuming its bad and throwing away money. Its a pretty bullet proof engine as far as rotaries go.