Hey brush up on your Czech and try this: MB.BOLINKO.ORG - Dok. serwisowa CD2
It's for cars, but it's very thorough. Good thing to have bookmarked if you own anything Mercedes-powered.
The site navigation stuff is in pig latin, poorly laid out, confusing, and sometimes redundant but the manual is in English. It was originally a program burned onto two discs so you have to click back and forth between CD1 and CD2 to get where you're going.
I frequent a cheap U-pull-it junkyard that usually has some 123 and 126 diesels, if you need any used parts from a car motor let me know.
Sorry I can't be of more help.