Stock k20a2, tested it myself at 185psi COLD in the dead of winter with the same comp tester I used today, put supertech 92lb springs and retainers in. And now I have 47-55 PSI max in 2/4 cyls, other two are most likely the same battery died so I didn't get them. I test cyl 2 and 4, the timing is dead on?(see pics) i'm totally lost at this point. Did reuse the head studs, and tried my best to follow the strange instructions for TQing the K-series engine studs. Pulled the head, cylinder walls seem fine, deck and head surface are ok too. If I had to blame something, i'd be the valves or the stupid head studs with that strange TQing procedure. Again I tested this thing in FEB with the same tester dead cold at 185psi.

 

I'm no expert, but having SOME compression in the cylinders points to head gasket or rings IME. Valves not sealing tends to give a 0psi reading. You mentioned the battery died before you could test the other cylinders, how fast was it cranking before when you tested #2 and #4? I would recommend doing a wet test with a freshly charged battery, or a leak down test if you have the equipment.

 

Leak-down isn't possible we don't have a 220/40v outlet in the house, or in my garage. Battery was ok, it was spinning the engine at a good pace. Head's going back on tonight, inspected the walls and deck/ head surface they didn't have anything that would make me suspicious. I just don't get how I tested it at 185 in the cold then after springs+retainers it's a complete POS, i'll do a full 1-4 dry test then wet, it'll help to know if it's the block or not.


By looking at the pics of the valves, they seem fine? just dirty?