I recently aquired a 93 del sol s (d15b7...5-speed) that had a burned exhaust valve in #4 cylinder.... replaced burned valve, reground old valves just enough to remove excess carbon build-up and seat the valves, installed new valve stem seals, and put motor back together.... car did not appear to be burning oil or smoking (actually ran pretty well on just 3 cylinders)..... now burning oil and smoking badly... 150-155 psi compression across the board... please help... don't want to hop up (well, not right now anyway) just want it to stop smoking... runs very smooth even though it smokes like a chimney.....

 

So it wasn't smoking before you worked on it? Are you 100% sure the new seals were installed properly?

 

Installed them per Hayne's manual instructions

 

Sorry I can't be of more help. I'm not an expert on this stuff, but, the only way I can see oil getting in the cylinders from what you did is the valve seals. I guess it could be something with the head?