Timing chain 96 Chevrolet Cavalier

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My son's 96 Cavalier ran out of gas. Car did crank after several attempts and drove back to drive way. Car then would not turn over. Mechanic says it's timeing. Using a new mechanic who says "timing located in engine " and will be very expensive.. How can I tell if this is really the problem? Can ran fine UNTIL my son let it run out of gas?? PlEASE HELP. NEED REPAIRS BUT NEED TO KNOW IF I SHOULD GET ANOTHE OPINION.... CONCERNED MOM