Hi everyone.....I have a b16a boosted. The engine is a stock build just changed bearings and rings. A couple month back I broke ring lands on three pistons due to over boost and boost spikes. I changed out the pistons and had the block honed while in the car with the machine's shop portable tool. The block had a few deep scratches so I decided to hone it out. After checking the piston to wall clearance the worst cylinder was 0.008" oversize, others smaller. I bought a set of 0.010" oversize rings (NPR) and replaced the rings filing the end gaps to 0.009" for each cylinder. I also changed the valve seals while the head was off. After running for two weeks to a month not a drop of oil was missing then eventually it starting taking oil in small progressions when I ran it hard in high RPMs only. NB: no smoke was visible at this stage. After two months of constant running the oil burning became worst and worst. Currently it burns a quart of oil every two days and smoke terribly from 5000rpm and higher. The engine has about 6-7 months since built. Note: I taught it was the turbo and I changed two turbos with the same exact problem. The turbo currently on the car came out b18 known to be working perfect. Can anyone help please? Three weeks ago I opened the engine took out the rings honed the block with a drill hone re-positioned the ring gaps and cleaned the ring grooves and mounted back up. It seems the situation has worsen since then. I don't know if it is the oil rings as the engine is pulling health and has good compression or if the rings are not seating properly.

 

Umm your p2w clearance was .008"???

 

How did you break the engine in? I wish I remembered the ring gap formula off the top of my head.

 

Bore in " x .005" for moderate turbo .0055-.0065" race set ups

 

Well that formula is for forged. I'm not sure for cast pistons and I'm also not sure what pistons OP is using