I've tried searching but can't find an answer for my exact problem.
I recently spun bearings on my previous motor, (built LSVtec) and instead of rebuilding it, I was able to find a great deal on a B16B locally.
The motor has been sitting for 2+ years, and the previous owner replaced the timing belt and head gasket in preparation to go in his own car. He sent me pictures that he had taken during the process, of how clean the inside of the motor was and how the factory cross hatching was still present. I tossed the motor in and its been having consistent oil burning issues. Idling and driving at a steady speed creates minimal smoke, acceleration creates noticeably more smoke, but it smokes most on downshifts and deceleration, especially down hills. Oil is pooling on the tops of all pistons, and the car won't drive more than 10 minutes without fouling out a spark plug and misfiring.
Now for what I've done:
Compression test, Obviously unable to do a dry test, but the wet test showed 235, 230, 230, 225 across the cylinders.
I borrowed a very cheap leakdown test kit from a friend. The results were so sporadic each time I used it that I ended up testing all cylinders 4 times to get extra numbers to work with. The best numbers from the set were 8%, 10%, 12% and 6%, but on some tests I would get as high as 50%, and immediately repeat the test and get a much lower number. I also could not determine where the leak was occurring, but it seemed to be past the rings.
I replaced the valve seals, (the old ones did seem to be very sloppy around the valves) and switched to a thicker oil but It has not gotten any better.
I pulled the throttle body off to try to see if oil was entering through the intake manifold but that doesn't look to be the case either.
I'm leaning towards the rings being bad but I'm stumped because the compression seems to be so good, and on the few times the leakdown tester was working properly, it seemed to give decent results (not ideal but not as bad as I would expect for how much oil I'm using). Has anyone else had this type of issue before and what solved it? Other tests I'm missing? It's difficult since this engine has a totally unknown history and has never ran for me properly. Any help or suggestions would be appreciated.

 

Valve guide seals. Its a failure as common as water on B series motors.

 

I would agree. Valve guides and valve stem seals need to be replaced. Once you stated that it oil smoked in vacuum (deceleration), that was the key. Very common on these engines.

 

 

are the valves wet? look at intake and exhaust port.

 

Check the guides for oil seepage. If it's getting into the piston domes, that's more than likely what it is if the seals were installed properly and the right sizes.

 

The old seals looked to be very loose around the valves. The new ones seemed to fit much better but I haven't been back in there since putting it back together. I'll take the manifolds off tomorrow to check on the backs of the valves.