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