Dear sir,
all my family comes from Sparone, in Piedmont and we are acquainted with many Giachinos. Please, let me know some more info about your granpa and when he moved to America so that I can search the local registers and give you a precise answer.
Maybe during your visit to Italy in 1986 none in the town was old enough to remember of your granpa.About the woman he married, Teresa Pica, was she also born in Sparone? I think there may be some spelling error, because a very common
surname in Sparone is PICCO, not Pica.
Waiting for further infos.