Melted RB20DET piston
This came out of my mates RB20DET a few weeks ago. The initial damage was due to detonation caused by a shagged fuel pump. The result was 20psi down on cyl 1. Pump was fixed and the motor ran great for another year or so at well over stock power levels. Eventually as the rings condition degraded, more oil was getting into the cylinder lowering the detonation threshold to the point it was pinging at stock boost. Eventually it let go in quite a dramatic fashion....and this was the result!