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