Hello and Help

Normally I do not introduce myself by starting a new thread. I have been a Scifi fan for 45 plus years. I have many thousands of SciFi books in all formats. I have all of the Edgar Rice Burroughs (ERB) books in first editions. While everyone thinks of Tarzan when they think of ERB I think of John Carter and the Mars series, and the lesser known Carson Napier of Venus Series. I am here to tell you the up coming Warlord of Mars movie looks like a dream come true. When I saw Tars Tarkas it was like he stepped out of one of the original illustrations in My books of Barsoom. My favorite period of SciFi is roughly 1930 till about 1970 or so. But I have contemporary favorites, of course John, Weber, David Eddings, Alan Dean Foster, Ben Bova,Brian Aldiss, etc. My favorite author, and my single favorite book has to be Clifford D. Simak's Goblin Reservation (1968). I am very pleased to be here.

Now for the help I need; There was a scifi book written, I think circa 1950. What I remember about it is there was an expedition to the outer planets that ended up on one of the the moons of Jupiter. They found the remains of a eons extinct civilization and discovered an underground storage area of their technology, some of which was still functional. Their space ship was destroyed but they managed to get home on a space ship built by this long lost civilization. This ship had engines made out of gigantic diamonds. Story wise it is a less beat you over the head version of Edward E. Smith's Space Hounds of the IPC minus all of the aliens. I probably have this book in PDF format but with something like 35,000 of them it is just impossible to look for it without more information. I don't have much hope but does anyone have a clue?