Cylinder head lower wall 16 extends over and closes opening 14 of each cylinder 12, while {HEAD ~ a piston upper portion} 18 closes {TAIL ~ an opening} at the lower end of each cylinder 12 
closes
Cylinder head lower wall 16 extends over and closes opening 14 of each cylinder 12 , while { HEAD ~ a piston upper portion } 18 closes { TAIL ~ an opening } at the lower end of each cylinder 12
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH