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Lightspeed Plasma Electronic Ignition

posted Mar 24, 2014, 8:23 AM by Bill Thomasson
Well this was a very scary part of the build.  The first thing I had to do was to drill and tap 2 holes to mount the mini-sensor.  You do this by drilling through the bolt holes in the propeller flange into the case and then tap the holes for #8 screws.  The instructions in the lightspeed manual call for 3/8" bolts, but the new Lycoming cases have a much smaller flange, so #10 is all that you have edge distance to do.
You can see the bracket going behind the prop flange, and just barley the top of one of the screws that had to be drilled and tapped.  At this point I also drained the preservative oil out of the engine so that I could turn the crank to position the bolt holes to drill the holes.  I then lock-tited the screws in.

Then I had to figure how to route the sensor wire.  I was planning on taking it down and under the cylenders, but there were really not any good mount points for an adel clamp to hold the wire.  I ended up taking it up and over the top of the engine.
Please don't critique the RTV, I was never good as a kid with finger paint.
White wire going back it the sensor wire.  

After getting the sensor mounted and wired (14 hrs), mounting the coils, testing the coils to determine firing order and installing the cables only took 3-4 more.  Much of the 14 hrs was hemming and hawing trying to decide how to do things.

To test the firing order I found top-dead-center of cylender 1 by removing the spark plug and watching the piston come up, and opening the valve cover and watching the valves as I turned the engine.  The crank did not have any markings that I could tell for TDC #1.   With the spark plugs out it was easy to rotate the engine by the flywheel, and the lightspeed ignition coils would arc between the coils at 25 deg before.  That then allowed you to know which of the RG-400 cables to hook to which coils.