I was at the hangar with my neighbor, the electronics engineer untill 11pm.
Moved both heavy cables to the same side. No change
Million other things without result.
Finally on one of the motors we shortened the ground wire to 6" and jumped the + with 1' piece of wire, instead of the long run from the engine room to the switch on the panel. 98% of the noise was gone. The long power wires are radiating the noise. With my friend's help we will rewire all the offenders. Some with shielded wire if we can not shorten the runs. Also I'm thinking of replacing my radio and transponder with something better. sick of trying to make junk work.
By the looks of it the rest of the plane tests will be done early summer :(
Thanks everybody for their advise.
Buly