Bendix 3000 Dual Magneto - Radio interference problem

[microlightgary]

Hi all,
G-AVKI has a SAUER engine which is fitted with the Bendix 3000 dual Magneto. One of the Mag circuits is generating huge radio interference (which goes away when that side is selected off).

Anyone have any suggestions as to what could be causing this? Its only done about 10 hours since a complete professional rebuild, which is doubly annoying...

cheers

Gary T

[Neil Spooner]

Hi Gary,
Check the routing of the P leads, it is worth shielding the P leads anywhere they run close to any aircraft power supplies to radio etc, or reurouting the lead away from the other power/aerial leads. Is the interference "all cylinders", or is it a particular cylinder?
If the interference is more pronounced on a particular cyl' then the shiedling may be defective on that cyl'. Are you running restistive spark plugs?
Neil

[G-ARBG]

Gary,

Is your mag fully boxed in as shown using the MKII firewall mag cover? Picture also shows screening of 'P' leads as per Neils recommendation above.
David G-ARBG
G-ASXI conversion using Bendix D-2000 magneto - 1980's(photo David Shrimpton)

[microlightgary]

David & Neil, TVM for your replies. The honest answer is that I'm not exactly sure quite how the magneto assy is located. We've just lived with the (bloody annoying) problem for now and will do some decent diagnosis when the weather gets a bit warmer!
At present all I can say is that the problem is only evident on one magneto and that the radio is powered by a seperate 12v gel battery, not run from the engine. We changed over to resistive plugs straight after buying the aircraft as that was one thing I could eliminate quite simply and cheaply.

Will keep you posted once I get chance for some more digging, many thanks

Gary