My friend messed up a valve while spraying his B16 and had all new valves put in that were a little bigger that stock. He also had the whole motor tore down and put new rings in. Now when he first starts it up it smokes a good bit until he starts driving. When he gets on it it hard it smokes again and sometimes makes a popping sound when he shifts like backfiring, im thinking it is detonating but i dont know for sure. What could be the problem for the smoking and popping?? The B16 is all stock except, I/H/E and isnt using oil.

 

What color is the smoke? Im guessing its white if hes not burning oil.

Check the headgasket.

 

its white, not blue. The head gasket is brand new from when they put the motor back together. Could it stille be the problem?? Some said it was running lean, anyh truth to this??

 

white smoke is burning coolant. You can smell the exhaust and it should smell slightly sweet (anti-freeze) if it is indeed coolant

It MAY be the innards of the new cat burning off and causing smoke. I don't know, Ive never replaced my cat so I have no first hand experience with that.

Check your radiator for oil, check your oil for coolant (will look like peanut-butter) and see what you find.