The eccentrics and {HEAD ~ cranks} associated with each piston and {TAIL ~ cylinder} maintain their parallel relationship while they are rotating 
associated with
The eccentrics and { HEAD ~ cranks } associated with each piston and { TAIL ~ cylinder } maintain their parallel relationship while they are rotating
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH