The Maggie Ignition Harness
By Mike Jones, Cessna Owner Organization Aviation Director
Often flying, we hear that momentary glitch. The soothing hum of our engine is rudely interrupted and we snap to attention. Is it too lean? Is it too rich? Is my engine getting enough air, is my fuel system clogged, do I have a bad plug, is my magneto going bad, or does my ignition harness have a problem?
Over the years, I’ve had my share of these conversations with myself in flight, and, from time to time I’ve actually had one of these problems! Looking to a future of trouble-free flight, I decided to upgrade my left, impulse-coupled, Slick magneto and install a SureFly electronic mag. As Jim Curns pointed out in his recent article on his SureFly installation [Cessna Owner magazine, March 2024], the installation was pretty simple, straight forward and the engine starts are amazing!
New Things Bring Out the Old
After my install was completed and with a test flight under my belt, I removed the cowl to have another look at the nice, new SureFly mag. It looked great, but boy, that 20+ year old ignition harness looked so shabby. What is with all the extra wire folded over itself here and there? My mind quickly extended this eyesore to the football-shaped electrodes of my spark plugs. I quickly made the decision to upgrade both the plugs and the ignition harness. The plugs were a no brainer and Aircraft Spruce came through lightning fast, as usual. However, in searching for the ignition harness I discovered that all too familiar, “Not In Stock.” I checked half a dozen suppliers for the Champion harness (my preference based on user comments) but all were backordered months.
How to Harness a Harness?
In searching through various forums, I found several references to a “Maggie” harness. I had never heard of this manufacturer, so I dug a little deeper. Maggie harness is the trade name for an ignition harness crafted by New Horizons of El Segundo, CA. Their website, www.maggieignitionsystems.com, had all the information I needed including product details, photos, and how to get an order started. I was particularly intrigued with the quality appearance of the finished harness and their patented screw in lead option for the magneto back plate. Oh yes, their “easy on the wallet” statement also caught my eye.
Contacting the Company
I sent them an email and quickly received a reply which started a useful conversation about what I needed, and the ever important lead times. They sent me a list of questions I needed to answer, which surprised me, as it seemed like the harness was going to be built specifically for my airplane as opposed to choosing a standard part number for a standard harness! That was exactly the case!
A Customized Order Process
To get the order started, I needed to specify the following:
- What style mag do I have on the left and the right: Bendix or Slick style? In my case, the SureFly (my right mag) is a Slick style magneto with respect to lead attachment.
- Engine make and model.
- How do you want the wire to exit the spark plug: straight out, a ridged bend or a “flexible” bend?
- Would I like the magneto end to have the traditional swaged wire assembly or Horizons patented screw in wire assembly, which makes fast work of changing a single lead if needed in the future?
- What size lead nut thread is required: 5/8-24 or 3/4-20?
- Blue anodized or plain spark plug nuts?
Since it is currently a trademark of their harness, wire color is blue and blue only. Now here is the icing on the cake: You can specify each lead length! I was floored. To make it a bit easier, they do have lengths for each plug based on your specific engine. But just to be sure the installation would fit perfectly, they offered to send me their assembly drawing with lengths for my specific engine and I could either keep what they have or modify lengths to my liking! After carefully measuring each lead length myself along the current routing, the drawing supplied was basically right on or plus an inch or so on one or two leads. I decided to just go with their plan.
The Final Quote
They took all of this information with a few back and forth messages to be certain everything was exactly as I wanted it and then returned a quote. I held my breath looking for both the cost and the lead time. WOW! $465 (includes BOTH left and right harness), plus shipping! Very reasonable! Lead time…3-4 weeks. An order of magnitude better, I thought. I placed the order and it went into the queue. I received the harness much sooner than expected!
Opening the Box
The box arrived via UPS with fragile stickers on the sturdy carton. I quickly grabbed my Swiss Army knife and dove in, camera ready to capture the moment! Sandwiched between a New Horizon/SureFly hat and an American flag was a really fine looking ignition harness! Earlier I used the term “crafted” to describe this New Horizon product. After seeing and handling the harness, that was the perfect choice of words. In addition, all the clamps and cable ties I would need for the installation were also included!
The Installation
Under the direct supervision of my A&P/IA, I carefully removed the old harness after photographing the existing routing, and installed the new Maggie Ignition Harness. All of the lead lengths were nearly spot on for all eight spark plugs. My A&P thought we could improve some of the routing, so we moved some and added other clamps to fit the plan. Unlike my old harness whose cover was thin and easily damaged, the Maggie harness has a strong temperature resistant protective cover over the shield and is very flexible in spite of being a bit larger in diameter. Under preventive maintenance as the FAA allows, I installed all new plugs to go along with the new harness. The only change was to open the spark plug gap to 0.022 as specified on the plugs fired by the SureFly magneto. The harness came with notes about proper torque values for the spark plug end and a suggestion to put some masking tape on your tool to minimize damage to the anodized finish. It was a bit difficult to do this as once the tape was used, the wrench was a very tight fit. Maybe, in the future, New Horizons could offer a polymer crows foot for your torque wrench and/or open-end wrench that would not mar the beautiful anodized hardware!
Conclusions
After completing the installation and the necessary paperwork, the test flight was smooth as glass and the engine indeed had that smooth, reassuring hum. At least for my time aloft in the test, there were no momentary moments of terror, and if I get one in the future, I can perhaps give some more weight to factors other than the ignition system, infant mortality of components notwithstanding! I had a great experience with New Horizons Maggie Ignition Harness, not only for customer service with a real interest in customer satisfaction, but also for a product crafted specifically for the application. It met my specific needs, at a reasonable cost, with better lead times. If you are researching a new ignition harness, give them a call. The Maggie Ignition System may be for you.
Mike Jones is the Cessna Owner Organization’s Aviation Director. He holds Commercial Pilot Certificates for both Airplane and Helicopter, is a Commercial Pilot for Unmanned Aircraft, is instrument rated, an active CFI, and has received the FAA Wright Brothers Master Pilot Award summer of 2024.
