{TAIL ~ The air exhaust passage} is arranged to exhaust {HEAD ~ gas} from the chamber, both passages respectively having an intake valve and an exhaust valve therein 
{ TAIL ~ The air exhaust passage } is arranged to exhaust { HEAD ~ gas } from the chamber , both passages respectively having an intake valve and an exhaust valve therein
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH