Nile, Could be bad valve seals if oil level is not going down noticeably. Have a compression and compression leak down test done on engine, the results from that will help diagnose compression issues or lack of which could cause smoking issue, internal engine coolant leaks will also be detected/checked with this test. Check the attached link,instruction and guide and diagnosing, Good luck
"I hope this helped you out, if so let me know by pressing the helpful button.
http://www.gregsengine.com/cylinder-leakdown-testing.html