I-8. Ukuthintela ukonakaliswa kwezixhobo ezibangelwe ngumthwalo, kukho into egqobhoza i-valve engalunganga kwi-valve engasebenziyo kwisixhobo se-hydraulic. Xa into ekhutshelweyo idlula umthwalo olingayo, i-valve egqithisileyo iya kulayisha ngokuzenzekelayo, kwaye i-hydraulic piller inesifo esikhulu esine-gonnage enkulu.