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Electronic Ignition... weighing it out.
I am coming up on 500hrs on my purchased flying RV7A. Dual Slick Mags. Running just fine. I read where I should have the Mags inspected to the tune of $500+ each. Reading about the fuel savings, non hot start issues, and inexpensive spark plugs have me thinking. The hesitations I am having is the rise in CHT and 100 hour inspections. (the P model E-Mag is what I have been considering). On really hot summer days, I can creep up over 400 degrees in a climb to a higher altitude if I want to do it in short order. I want my motor to last long beyond the 2000 TBO. I am only 4 years into aircraft ownership and maintenance and I have to admit my ignorance and inexperience with how the temps truly effect the motor. I have seen some folks say they see 20 degrees higher CHT with EI. Is this worth worrying about? Is that rise at a given fuel flow and making more power with the EI and just reducing the fuel flow would render the same CHT and power that the mag was producing with using less fuel? Can someone speak to the number of trouble free hours they have had out of P-model Emags? How long does your 100 hour inspection take?
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I've had NO trouble free hours using pmags... Over 700 hours of trouble flying with ElectroAir's. One of the common problems with pmags is high CHT's. Electronic ignitions are great when they are installed and working properly. Easy starts hot or cold, smoother running engine.. I can't say the fuel economy is better since I never sat and compared. After running a single ElectroAir and mag for many years I pulled the mag and have been running dual ElectroAir's for more than 5 years.
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Please keep in mind that these troubling CHT increases are related to an improper advance curve - the fact that it's electronic has nothing to do with that. Improperly timed Magneto's will cause the same problem.
Select the product that has the proper curve and you are golden. |
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I only run dual pMags (other than the RV-10 - but now have a six cylinder pMag in hand waiting to install on it). The RV-10 was my first experience with mags, and was a constant source of irritation (timing, maintains and especially plug cleaning) as I was spoiled from running dual pMags.
800 hours in an RV-8A with an IO-360 (parallel valve). Absolutely zero issues. I offer high CHT stories are not all that relevant for the majority of people. Run the pMag(s) with the timing jumper in and fly on. I have some 300 hours running another brand of electronic ignition that had multiple problems from the first day, including two hard in flight failures. These ignitions were replaced with pMags. If you do not take the time create a bullet proof power source for any EI other than pMag, you should just stay with mags. Carl About a month away from first engine start on the new RV-8 project - running dual pMags. |
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Search on my username, there are a number of posts about properly timing P-mags. Check your PM's. |
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I have two comments:
#1, You can vary your P-Mag timing from inside the cockpit if you add one of the interfaces (m-mags or other), so you could easily run a more favorable advance when climbing and then increase the advance for cruising. This would be an improvement over your current fixed timing. #2, I would not avoid an upgrade because of a cooling issue. I would fix your cooling issue. It is either fuel flow or cooling air flow. Each are relatively easy to correct with some experimentation. I had duel magnetos and after the third overhaul decided the p-mags would pay for themselves. I am very happy with them. I use the engine bridge to allow me to very the timing via my I-phone, but I never do. |
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Our O-360 is consistently burning a little more than 1gph less fuel than delineated in Lycoming's power charts. At 1gph the payback on investment in electronic ignition is very fast indeed. By my calculations, the single P-Mag on our engine has fully paid for itself by the time we hit the 500 hour mark. When we get to that 500 hour mark the impulse-coupled Slick on the engine will be turfed in favor of another electronic ignition. The fuel savings with the second EI is a small increment over that saved by the first but by then I suspect I will have much better confidence in EI and greater willingness to be fully electronic. So far (~200 hours) the P-Mag has provided excellent service. |
Jeff, read the link below a few times, available courtesy of the author. And remember, as others have noted, electronic ignition does not increase CHT. Timing advance does. Some EI's offer full control of advance, including none at all.
https://www.danhorton.net/Misc/Nigel...Advance%20.pdf |
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