Ok here's a short history i got my 1983 mazda rx7 from my grandpa, has a vacuum leak and a rebuilt carburetor. I haven't started it in a month so i put a gallon of gas in it because it was on empty, i started it but it seems to run a little rougher now but there's thick white smoke coming out of the exhaust. i think its burning of oil in the exhaust but i need a second opinion

 

Sounds like you've got coolant leaking into the combustion chamber because of an O ring failure.

Actually one of the better ways for a 12A to die, since the innards are probably in good shape as long as you don't cause any further damage, so you've got the important stuff for a rebuild.

 

what do you mean is my engine going bad? shoild i plan ahead for an engine swap?

 

I believe Ray is suggesting you rebuild instead of a swap.
In the attached image if the red O-ring fails at some point then coolant will enter the combustion chamber.

 

How bad is the white smoke? Most of the engines I start that have sit a long time do smoke pretty bad for even hours, but they usually stop.

My friend has a motor that sat for 8 years, smoked like a train the whole day we got it started at first. It was wispy white smoke too. I warned him not to freak out, and sure enough after a good oil change, coolant system test, carb rebuild, and new spark plugs it stopped.

And it hasnt again since!

I also have a 12A that smoked badly on the engines deceleration for over a year. I was convinced it needed rebuilt too, but one of our friendly roadracers here on the forums persuaded me to run 15-50 Mobil and Lucas oil stabilizer and now it doesnt smoke at all.

 

Yeah give it a chance to get warmed up and run a bit. It may go away or lessen.

 

yea the smoke whent away after about 2 mins but i definetly dont have enough money for a rebuild yet but even if i did i would probobly want a newer rotary engine like a 13b or something

 

That's good news, sometimes those oil and water seals just take awhile to get back to work after a long layoff.

If it's really a water seal leak, it will be obvious, lots of white steamy smoke coming from the coolant, kind of like you originally described. But it won't go away.

On the other hand bluish-white smoke is usually oil related and like Tim and the Carb Whisperer say, a little oil conditioning to soften the seals can often reverse the problem.

I've used Golden Eagle engine oil Stop Leak with very good success on the internal and dowel pin oil leaks:

No Leak® Engine Oil Stop Leak | Gold Eagle

 

I just noticed your title was "Wankel whisperer". :P

 

We are all whispering those few remaining 12A housings, do me a favor Joe and don't mess up those ones you got.