Uburebure bwa piston hejuru yubutaka bwiyongereye mugihe kugirango umutekano wa silinderi umeze. Kubera ubwiyongere bwubutaka bwo hejuru, kubitsa kubutaka bwo hejuru byabaye ingorabahizi kuruta moteri ngufi zo hejuru. PC-ring yatangijwe kuva 2000. （PS ： Kugirango iterambere rya piston rizashyirwa ahagaragara mumutwe mushya.

Impeta yo koza piston itunganijwe hejuru yumurongo wa silinderi.Impeta yo koza piston yashyizweho kugirango irinde kubitsa cyane kubutaka bwikamba rya piston ikuraho ibyabitswe mugihe piston yegereye ikigo cyapfuye (TDC).
Impeta yo gusukura piston ivugururwa hamwe no gukusanya uburambe.