Sci Fi thriller series read in the late 70s or early 80s, man cloned to solve mysteries, body would break down after a few weeks

[Sven]

In the late 70s or early 80s I read a series of Sci Fi "Mission Impossible" type thrillers. The hero was an ex-author, dying of cancer, whose mind is transferred into clone bodies. The bodies only last a limited time. While they last he investigates mysteries, which usually had science fiction themes.