The piston was wearing on its surface facing front of the engine. I removed the piston and turned around 180 deg,
put everything back together and tried again. Piston was wearing on the same side although this time facing back
of the engine. That's why I suspected bent conrod. Took conrod out, inserted straight longish steel rods through
both brass bearing of conrod (fairly tight fit) to chech if rods are parrarel. Were skewed a few degrees, so I bend
conrod slightly until rods were parallel. I did not help regain compression, buy I will try to run the engine again,
hopfully without piston side wear.