The intake/exhaust valve member is axially movable within the combustion chamber, and operatively cooperates with {HEAD ~ wall structure} of {TAIL ~ the combustion chamber} 
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The intake / exhaust valve member is axially movable within the combustion chamber , and operatively cooperates with { HEAD ~ wall structure } of { TAIL ~ the combustion chamber }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL