i have a 1986 N/A rx7. some times it smokes alot but others it doesn't smoke at all until 4,000 rpms then smokes when i shift. Is this an internal seal or could it possibly be the oil metering pump? Please help me, how do i fix it?

 

If its blue smoke, its oil getting past the oil control rings on the rotors. This would be the same as oil getting past the piston rings on a piston engine. It would require a tear down to get inside the motor to replace the oil rings.
If its white smoke, its coolant getting past the coolant seals which are sandwiched between each housing. Again, can't get to it from out side the motor.
Black smoke is when you burn lots of gas, which would mean you are running rich and need a tune up/ troubleshoot air and fuel systems and possibly emission control system. Burning coolant will mess up the internal parts of your motor. Coolant will cause rust on the steel apex seals and machined surfaces of the engine, and is also corrosive. Burning oil will leave lots of carbon in the motor, but isn't really detrimental to immediate functionality. Eventually will need rebuild to correct problem, as the leak will gradually become worse.