FlyDave Posted June 17, 2016 Report Posted June 17, 2016 I have a 1989 Bravo with 1800 hours TTAE. It's just out of annual and after the inspection my mechanic mentioned that the original ignition harness is 27 years old and is chaffed through the outer braid in a number of places. He has seen other planes with similar aged harnesses that, after replacing, saw a smoother running engine. Don Kaye said my engine runs as smooth as his during my checkout but I haven't personally flown any other Bravo's. I will fly in JCollier's new-to-him Bravo next week - that will be the 2nd Bravo I've flown in so I'll have something to compare my plane to then. My plane is turbocharged and I typically fly it in the high teens to low FL's. I think this put's a more stringent requirement on all power plant components. We did the 500 hour on my mags last annual and I put 12 fine wire plugs in about 100 hours ago. So both ends of the ignition system are fairly fresh. So I put these questions out to the group: Do I replace the harness based on time in service - 27 years and 1800 flight hours? If you say replace then do you prefer Slick or Kelly harnesses? I have Slick 6360/6361 mags. Dave Quote
N601RX Posted June 17, 2016 Report Posted June 17, 2016 If its still running fine keep using it. When you overhaul depending on which option you choose your most likely going to get a new one anyway. Its also easy to replace a single wire or end if one particular wire is a problem. Quote
Marauder Posted June 17, 2016 Report Posted June 17, 2016 Just now, N601RX said: If its still running fine keep using it. When you overhaul depending on which option you choose your most likely going to get a new one anyway. Its also easy to replace a single wire or end if one particular wire is a problem. I have asked my mechanic the same question pertaining to a really tired looking set of wires and he came up with your answer. Do you think high altitudes would have an impact? Quote
FlyDave Posted June 17, 2016 Author Report Posted June 17, 2016 40 minutes ago, N601RX said: If its still running fine keep using it. When you overhaul depending on which option you choose your most likely going to get a new one anyway. Its also easy to replace a single wire or end if one particular wire is a problem. The Bravo conversion (new cylinders) was done at 1,000 hours so I"m hoping to go to 2,400 - 2,500 before overhaul. 39 minutes ago, Marauder said: I have asked my mechanic the same question pertaining to a really tired looking set of wires and he came up with your answer. Do you think high altitudes would have an impact? I would think high altitude would impact this decision in favor of replacement. Did your mechanic provide a statement or just the question? Quote
Marauder Posted June 17, 2016 Report Posted June 17, 2016 Just now, FlyDave said: The Bravo conversion (new cylinders) was done at 1,000 hours so I"m hoping to go to 2,400 - 2,500 before overhaul. I would think high altitude would impact this decision in favor of replacement. Did your mechanic provide a statement or just the question? He recommended not changing mine out. He did replace the end on one of them but kept the wire. I think I heard our esteemed Canadian colleague also say to keep them as well (M20Doc). I'm with you, I like pretty. Mine look like a rat would reject them for bedding material. Quote
carusoam Posted June 17, 2016 Report Posted June 17, 2016 If it has an armored braid under the rubber skin... It is physically well protected. The electrical insulator is under the braid... It is probably made of some really long lived Teflon based polymer. Stable for eons. Ends can be inspected for wear and tear... Resistance can be measured... Check to see if it is tied down properly using the proper hardware... What is the cost of a new harness? I replaced my C's harness after about 40 years. Dissapointing that it netted no gains other than it looked nicer. Blue silicone in place of dirty black... PP thoughts, Dave knows I'm no mechanic.... Best regards, -a- Quote
ArtVandelay Posted June 17, 2016 Report Posted June 17, 2016 In my experience, the first indication of a degrading harness is hard starting in raining conditions. Something about the high humidity causes the high voltage current to leak easily. Quote
Jim Peace Posted June 17, 2016 Report Posted June 17, 2016 (edited) I just replaced my Slick harness in my C 180hp...to a Kelly about 30 hours ago.....so far so good....I do think it runs the same if not better...Also did the 500 hour mag and fine wires about 150 hours ago.... I like to have nearly 100% dispatch reliability. I have crossed the country three times now in just over a year....I overhaul and replace stuff sometimes just because it is Tuesday... If I decide to sell my plane someone is going to get one hell of a deal...... my thread for my issues: Edited June 17, 2016 by Jim Peace Quote
Guest Posted June 17, 2016 Report Posted June 17, 2016 Age has nothing to do with serviceability of the harness, the wires are metal spring steel or multi stranded. Most wear through the outer braiding from lack of proper clamping and securing. They can be tested with a multi meter or with a high tension ignition tester. Individual wires , spring or nuts can be replaced. Clarence Quote
FlyDave Posted June 18, 2016 Author Report Posted June 18, 2016 Thanks for the input guys. I guess I'll burn up some dinosaurs instead . Dave Quote
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