One of my books gave a German expected time between overhaul of 25 hours, but in actual service, averaged 17. A book on Russian aviation confirmed the time of 15-17 hrs before failure of The German 004B engines taken from Junkers. The Russian copies were of lessor quality which is why the early Russian jets used the German 004B (MiG-9, Yak-15). The Russian assembled 004B engines from German parts ran less than the German average of 17hrs. It would take a while to find the sources.