My RX7 Smokes really bad for about 15 - 20 minutes after start up. It's white smoke but goes away and does not smoke anymore and runs real fine. It's not a head gasket issue. Have an idea that it is a fuel injector problem. If the car sits too long it leaks fuel into the rotar housing. Could be wrong. Anyone have a different take on this. Looking forward to hearing from you.

 

Head gaskets are only on Piston engines..see if you can familiarize yourself with the operation of the Rotary engine..(not bashing you just tryin to help you out here.)
Look at the GENERAL Rotary Tech Support Section as I just moved a Thread that has an illustrated link to the operation of a RX engine.
...and to me,with what you stated?..it's a bad coolant seal problem..white smoke says coolant is entering the combustion chamber and being burned off.
Now,it may only enter when the car is cooling down or dormant after being ran but never the less it is telling you that a rebuild is in your future.