This should be a lesson to all aircraft owners to keep a tight rein over their logbooks and maintenance records. It's amazing how many people don't keep their aircraft logbooks up to date and allow them to float around not knowing where they are. Aircraft without proper logbooks are almost worthless because of the difficulties in trying to reconstruct their details. In the case of engines its more or less necessary to zero time them as this is the only way of validating their authenticity; not cheap.