the 617 requires 135 bar opening pressure; the injector body part number for the OM617 is KCA30S35 and as bigblockchev noted the threads are different (the 190D injector threads are on the very bottom, whereas the 300SD are further up). i think you can get remaned injectors for about $70 complete or find a diesel service shop that will rebuild yours (probably cheaper if you source the nozzles for them)