Today I completed my ignition conversion from dual P-mags to one impulse coupled slick mag and a Lightspeed Plasma II+ with crank sensor. I'm a very happy camper.
A little background: I am flying a RV9A with a new Mattituck O-320. I flew it with dual P-mags for 100 hours. I had three ignition failures in that time. Each on a unique unit and in each case the failure was that the ignition wasn't firing at all. The rest of my failure details can be found with a little research on my build log.
I decided to remove both P-mags, after the last failure, and install one impulse coupled Slick mag on the left, and one Lightspeed Plasma II+. I called up Mahlon at Mattituck and told him what I wanted to do. He said he would call me back within the hour with a parts list and order prepared. As promised, he called back and rattled off all the parts and pieces that I would need. New mag studs on the left, some nuts, washers, impulse spacer, gaskets, ... He had thought of all the little stuff that I probably wouldn't have. That is service well worth paying for. All of my parts arrived and off came the P-mags.
I removed all of the wiring associated with the P-mags. Ground, power, control, for each unit. That is quite a bit of wiring when you have it all extracted from behind the panel. The left mag studs in the accessory case were replaced with longer ones that could accommodate the slick impulse spacer. The right mag hole was covered with the Lightspeed mag cover plate.
Most people have a lot of experience with magneto installation, but this was a first for me. Wow, that was easy. One shielded single conductor wire was run and terminated with plenty of strain relief. Bada-Bing..Bada-Bang, one mag installed, timed, and ready to go.
The Lightspeed retrofit was a different story. First off, I did the crank sensor trigger which is simply more work and we know it. I removed the prop and flywheel, and marked the flywheel for installation of the trigger magnets. I double, triple, and quadruple checked the positions of the magnet installation before drilling the flywheel. I installed the magnets with loctite and staked around the sides. Setting the gap was a little tedious. I used a combination of adding washers and removing material from the aluminum spacers.
With the prop reinstalled, I turned my attention to the rest of the electronic ignition install. The biggest trick was finding a place for the Plasma II+ control box. I have this airplane pretty well packed full of electronic toys, and most everything is between the sub-panel and the firewall so that the space between the instrument panel and the sub-panel looks very clean (tip-up). So there was literally no place to mount the control unit. I ended up making some brackets to mount the Plasma II+ to the firewall just behind and slightly above the pilot's rudder pedals on the cold side. I can't begin to describe how interesting it was to mark, drill, deburr, dimple, and rivet those brackets in place in that location, but Tanya and I are pros at those kinds of impossibilities after building a whole airplane and shooting every rivet.
I punched two new holes in the firewall for the Plasma trigger wire and coil wires. I used a small greenlee punch, the only way to go when punching a hole in the firewall. Routing of the trigger wires was a little challenging, but I think I got it figured out. High temp RTV is my friend. The coils were pretty straight forward to bolt on and wire up. I made cover plates for the right side spark plug wires and mag blast tube holes on the back baffle.
The next problem to deal with is tach signal. Previously I pulled my tach signal off of one of the p-mags. I didn't want to mess with a tach signal on only one of the ignitions so I decided to use the Vans mechanical to electric signal thingy. Order Up! I got the remote unit that uses a short 12" tach cable. Surprise, there is no way to screw that tach cable on to the accessory case with the 90deg oil filter adapter AND the SD-20 backup alternator on the vacuum pad. The backup alternator was removed and reinstalled after the tach cable was installed. I made up a bracket to mount the sender to the firewall and riveted it in place. The Vans sensor uses 12V, Gnd, and signal with a tach pulse of 4 p/r.
Much care was taken throughout to be sure this wasn't a sloppy retrofit. It is very tempting to start cutting little corners on the quality of work when doing changes after flying. I think I successfully resisted. I went back over everything FWF with a fine tooth comb, Tanya cleaned up the interior and reassembled the seats, carpets, headsets, and generally re-setup for flight. All of this took me 25 days which felt like way too long after flying 100hrs in the previous four months.
The first test run-up with the new ignitions confirmed that the timing was spot on and it ran perfectly smooth. I re-cowled and prepared for flight. I treated this flight with much respect just as if I were back in Phase I. "Blast off" was exactly that. It was severe clear in central Texas with temps around 52deg F. I had that big stupid grin on my face (solo) as I turned crosswind at 1300' AGL. I orbited the field for about 20min. I did an in-flight mag check and it reacted exactly as on run-up. 90rpm drop on the mag, 15rpm drop on the lightspeed. This setup is flawless so far with two hours of run time.
The unscientific performance comments: It idles much smoother at lower idle speeds. Tanya even noticed it during the second "passenger" flight. That is really saying something when she notices the difference. The high power feel is smoother as well. I'll refrain from suggesting that there was "more" power, because the weather (low temps) was so much different. Which leads me to a basic question. If the lightspeed only has a very small mag drop at run-up and during flight, why does the p-mag always exhibit 100-150 rpm drop when running on only one unit?
Only time will tell, but this pilot and builder is very happy to have made the conversion.
A little background: I am flying a RV9A with a new Mattituck O-320. I flew it with dual P-mags for 100 hours. I had three ignition failures in that time. Each on a unique unit and in each case the failure was that the ignition wasn't firing at all. The rest of my failure details can be found with a little research on my build log.
I decided to remove both P-mags, after the last failure, and install one impulse coupled Slick mag on the left, and one Lightspeed Plasma II+. I called up Mahlon at Mattituck and told him what I wanted to do. He said he would call me back within the hour with a parts list and order prepared. As promised, he called back and rattled off all the parts and pieces that I would need. New mag studs on the left, some nuts, washers, impulse spacer, gaskets, ... He had thought of all the little stuff that I probably wouldn't have. That is service well worth paying for. All of my parts arrived and off came the P-mags.
I removed all of the wiring associated with the P-mags. Ground, power, control, for each unit. That is quite a bit of wiring when you have it all extracted from behind the panel. The left mag studs in the accessory case were replaced with longer ones that could accommodate the slick impulse spacer. The right mag hole was covered with the Lightspeed mag cover plate.
Most people have a lot of experience with magneto installation, but this was a first for me. Wow, that was easy. One shielded single conductor wire was run and terminated with plenty of strain relief. Bada-Bing..Bada-Bang, one mag installed, timed, and ready to go.
The Lightspeed retrofit was a different story. First off, I did the crank sensor trigger which is simply more work and we know it. I removed the prop and flywheel, and marked the flywheel for installation of the trigger magnets. I double, triple, and quadruple checked the positions of the magnet installation before drilling the flywheel. I installed the magnets with loctite and staked around the sides. Setting the gap was a little tedious. I used a combination of adding washers and removing material from the aluminum spacers.
With the prop reinstalled, I turned my attention to the rest of the electronic ignition install. The biggest trick was finding a place for the Plasma II+ control box. I have this airplane pretty well packed full of electronic toys, and most everything is between the sub-panel and the firewall so that the space between the instrument panel and the sub-panel looks very clean (tip-up). So there was literally no place to mount the control unit. I ended up making some brackets to mount the Plasma II+ to the firewall just behind and slightly above the pilot's rudder pedals on the cold side. I can't begin to describe how interesting it was to mark, drill, deburr, dimple, and rivet those brackets in place in that location, but Tanya and I are pros at those kinds of impossibilities after building a whole airplane and shooting every rivet.
I punched two new holes in the firewall for the Plasma trigger wire and coil wires. I used a small greenlee punch, the only way to go when punching a hole in the firewall. Routing of the trigger wires was a little challenging, but I think I got it figured out. High temp RTV is my friend. The coils were pretty straight forward to bolt on and wire up. I made cover plates for the right side spark plug wires and mag blast tube holes on the back baffle.
The next problem to deal with is tach signal. Previously I pulled my tach signal off of one of the p-mags. I didn't want to mess with a tach signal on only one of the ignitions so I decided to use the Vans mechanical to electric signal thingy. Order Up! I got the remote unit that uses a short 12" tach cable. Surprise, there is no way to screw that tach cable on to the accessory case with the 90deg oil filter adapter AND the SD-20 backup alternator on the vacuum pad. The backup alternator was removed and reinstalled after the tach cable was installed. I made up a bracket to mount the sender to the firewall and riveted it in place. The Vans sensor uses 12V, Gnd, and signal with a tach pulse of 4 p/r.
Much care was taken throughout to be sure this wasn't a sloppy retrofit. It is very tempting to start cutting little corners on the quality of work when doing changes after flying. I think I successfully resisted. I went back over everything FWF with a fine tooth comb, Tanya cleaned up the interior and reassembled the seats, carpets, headsets, and generally re-setup for flight. All of this took me 25 days which felt like way too long after flying 100hrs in the previous four months.
The first test run-up with the new ignitions confirmed that the timing was spot on and it ran perfectly smooth. I re-cowled and prepared for flight. I treated this flight with much respect just as if I were back in Phase I. "Blast off" was exactly that. It was severe clear in central Texas with temps around 52deg F. I had that big stupid grin on my face (solo) as I turned crosswind at 1300' AGL. I orbited the field for about 20min. I did an in-flight mag check and it reacted exactly as on run-up. 90rpm drop on the mag, 15rpm drop on the lightspeed. This setup is flawless so far with two hours of run time.
The unscientific performance comments: It idles much smoother at lower idle speeds. Tanya even noticed it during the second "passenger" flight. That is really saying something when she notices the difference. The high power feel is smoother as well. I'll refrain from suggesting that there was "more" power, because the weather (low temps) was so much different. Which leads me to a basic question. If the lightspeed only has a very small mag drop at run-up and during flight, why does the p-mag always exhibit 100-150 rpm drop when running on only one unit?
Only time will tell, but this pilot and builder is very happy to have made the conversion.
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