You also have blue smoke comming out?
You are burning the engine oil.
As you changed the heads, and hopefully the gaskets at the same time, that's not the cause. This also rules out the valves sleeves leaking oil.
It looks like the segment of the pistons are broken or worn out. It also can be the cylinders that are ovalised to much, preventing adequate contact with the segments.
It's a big, and dirty, job opening the engine to replace the segments, but can be done by a determined and properly tooled amateur mechanic.
If the cylinders need recalibrating, you need to have access to some specialised tools: An inverted lathe. Normaly, only some mechanic shops have them.
It may be cheaper to just replace the whole engine...
Electro
March 2013