ur right bout the rings an bores (if u mean the bottom end im still learnin bout my car) i do need a change maybe 1.8 not sure yet,
my oil cap was jus 2 slidy up an down were it sits, there was no tightness 2 it at all ( dyno tuner did say after the session i needed new rocker cover an cap), dont no if its normal like that but wen i changed it, it did get rid of the noise, but i understand were ur cumin from u do no ur stuff well more then me mate