I took the block to the machine shop today. Not a good sign when a seasoned machinist goes "oh my god" seeing the cylinders
If 0.5mm won't do, I'll need to source another block. I'll be wiser next week... I ordered the SR20DET pistons too.
Got the valves off too! Some where really tight, some fell off on their own. I think new guides are in order and the valves themselves...
There's no way in hell those could be
ever used again.
Here's the block sans valves:
Valve guides protrude only by few mm into ports. Ports are too filled with oxidized stuff to say anything about the surface.
and finally, a first-ever subjective view of a spring compressor tool:
That piece of waste had so bad threads they froze up even without load... damn.