Ok...very common problem. I just bought a 1990 760 turbo (to replace the totaled 85 :) and it had the common balancer slip problem. I took the fan belts off and spun the balancer right off by hand! the easiest way to fint TDC. If you made marks on the old belt, and it did run, you could line up the camshaft mark, and the crank should be on TDC. The intermediate shaft really doesnt matter as long as you distributor is on the back of the cyl head, which it should be on you car (and there isnt a balance shaft either, so put the intermiedate shaft as close to the mark as you can.) You can also take out #1 spark plug, and stick something down the hole to see where the piston reaches TDC, but be careful not to jam something in there when the piston comes up, and turn the crank by hand. Now that im thinking, you have to replace the balancer anyway, right? Go get a new one, and put it on, with the lower timing cover on. the balancer only goes on one way. set it on TDC according to the cover, take it off, line up the others, and slap the belt on. if it makes you feel better, you can also start the car momentairly with just the lower cover and the balancer bolted up. if it starts right up, you are good to go, let it idle for a sec to see if the idle is normal, if the belt is off a tooth, it wont idle at the correct speed. and no the b230 IS NOT AN INTERFERANCE MOTOR. if the belt breaks, the car stops. thats it. or at least thats what ive seen from expireance. so put the new balancer on, set tdc, take it off, put the belt on.
good luck!
Mark