The secondary lobes cause an associated valve to open slightly and close completely prior to {HEAD ~ the normally expected valve opening} caused by {TAIL ~ the primary lobe} 
caused by
The secondary lobes cause an associated valve to open slightly and close completely prior to { HEAD ~ the normally expected valve opening } caused by { TAIL ~ the primary lobe }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL