Magnetron Ignition Modules

[Bryan Cotton]

Do you have a ground going to the body of the magnetron? If not, you may have been getting some ground through the anodized aluminum and then that went away. My magnetrons didn't work right until I added that wire. I basically put a lug under the mount screw, against the magnetron body, and ran it to my ground.

[thomasjones42]

Thanks Bryan. I'll check that out.
Tom Jones

[WaiexN143NM]

hi all,
Tom jones you on your second test flight?
Yay!! you finally got into the air!
Congrats!



michael.

[karmarepair]

Just finished my second test flight yesterday and while my turbo engine seems to be running fine when I tested the mags at idle (turned off the 12V ignition) taxiing back to hangar, the engine died. Restarted immediately on 12V ignition. Tried another time with same result. Seems odd that both mags would apparently fail simultaneously but that appears to be the case or am I missing something. Anyone have any thoughts?

The "primary" ignition on my Sonex project has given me and my build buddies FITS. ONE magnetron failing IS enough to kill the engine, as the spark from this system is weak (note the TINY gap on the Primary ignition - if it had more spark energy you could run a bigger gap), and killing one magnetron kills two cylinders. You can read about our trials and travails here http://eaabuilderslog.org/?blproject&sh ... xebwn&sid=
I have two brand new magnetrons we have not yet tried on the airplane, as they changed the way the spark plug leads exit the modules, and I have an early production (circa 2000) accessory case, and they don't quite fit - some work with a die grinder should fix that, but I'm about ready to pull the magnetrons that are on there now off, give them the float test, and replace them with a Simple Digital Systems Coil Pack Ignition. I haven't done it yet because it's $900, I have to fab a mount for the Hall Effect sensor, figure out where to mount the coil pack on our very tightly cowled installation, I like the THEORY of a self-generating ignition that is independent of the alternator, etc, so I may pull the engine AGAIN and put the last set of magnetrons on. ONE of the existing modules IS firing. It IS possible to change the magnetrons with the engine still on the plane, but it's HARD.

There must be a couple of hundred of these engines running, and it seems rare to have such troubles with the Magnetron primary ignition, but my installation certainly is having them.

The magnetrons we use are for a Briggs and Stratton opposed piston flathead engine that is not made anymore; the modules are aftermarket, made Who Knows Where. See attached for what I believe is the schematic for the magnetrons, which is DIFFERENT than the single cylinder Magnetrons used on CURRENT Briggs and Kohler V-Twins.

[Bryan Cotton]

I also had the same thing happen. You can remove the spark plug wire from the ignition module. The wire is glued into the module and there is also a screw stud in the hole that the wire goes in. By forcefully twisting and pulling the old wire will come out...you may also need to dig out some glued in insulation. I replaced my wire with a Ford tractor spark plug wire that had a solid copper core. Bought a set of wires on Ebay....the tractor wires were the correct size to fit the hole in the module.

I've joined this club. Anybody else replace magnetron wires? Any Amazon, eBay, or other links to parts?

[GraemeSmith]

I can tell you this one fits perfectly - and works fine - and costs $34:

https://smile.amazon.com/gp/product/B0009XHKDS

[bvolcko38]

I bought 10' of wire on Amazon, "Rotary Corp Wire Spark Plug 7mm X 10' "

[Bryan Cotton]

Thanks Graeme and Bill! Bill, what did you use for the spark plug terminal?

[Bryan Cotton]

New vs old magnetrons - the one with no wires came with my Aerovee kit and had the P lead problem. The one with one wire removed was the replacement. The old magnetron has a screw interface and the new one just has a pin. Very easy to take apart. The glue does all the retention.

[GraemeSmith]

Bryan - spark plug ends and crimper:

https://smile.amazon.com/gp/product/B082MFZRFH

I use it to repair worn or broken ends - but as to replacing a wire on a $35 part...........

With the hassle and risk of not doing it right - I think $35 is a pretty good deal.