I'm afraid we would need more information than just their name. Grandfather's birth date? location? great grandfather's name? It is easier to find people between 1860 and 1940.
Also you might want tags like "brickwall" and "genealogy" instead of "on" and "my".
Also a profile link if they are no longer living?
Ok, I see you are brand new so you wouldn't know a profile. But we would need as much info as possible of non-living members to find them.