Yesterday afternoon I got ready to change the timing chain on my 1981 240D. I removed the fan and shroud and the glow plugs, then the valve cover. I checked the timing chain wear and it was at 5 degrees retard. This aft., I got ready to actually do the change. I removed the tensioner and the plastic guide. I grounf off the heads of the chain pins, and fastened the new chain to the old. I held on to both chains while my helper cranked the engine around with a socket on the damper nut. I held as tightly as I could, but it is possible that one or the other of the chains jumped a small amount. At any rate, we got the new chain nearly all the way around, and fastened together with the new link(not peened yet). About 90 degrees from having the new link on top of the cam sprocket, we could no longer turn the engine over. The chain was tight on the drivers side. We can move the chain about 30 or 40 degrees total, back and forth, but no further. Haynes manual says engine must now be disassembled to correct this situation. I have searched the archives but found no help. I did hang on tight to both ends of the chains while turning the engine around. Does anyone have any good advice for me? Thanks to all.