I need to get behind the front timing chain cover on my 89 735i
but the crank nut seems impossibl to loosen.
have already tried socket and long bar
then impact bar
then heat and all off the above again but this nut wtll not loosen.
what am I missing here?

Is it possible the crank nut has left-hand threads?

NO ! ! the nut is RIGHT hand thread, they're VERY tight. Without the crank lock tool & 3/4" drive set, the best way is to carefully air chisle it off. Do Not try if you haven't used an air chisle before, you might damage to nose of the crank. Careful work with a heavy chisle and 'drilling' hammer should do it.
Obviously, you'll need to replace the nut when your done. Happy hammering ! !

take that long pull handle and put it on the nut, turn the engine clockwise until the handle contacts the frame of the vehicle. bump the starter.

I am assuming you have tried some kind of lubricant like penetrating oil.

Just a note, I've tried this method on a couple of M30's with no luck, I used it years ago an American engines with success but it may be the large thread size, nut & torque spec. that kept it from working for me on M30's.