Ignition harness

Chip Sylverne

Chip Sylverne

Final Approach
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Jun 17, 2006
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Quit with the negative waves, man.
So went out to do a little flying yesterday, and the JPI showed #2 cold on the left mag. Pulled the plugs, cleaned em, reinstalled. Same thing. Put in two new plugs I've been saving. Same thing. So I figure I have a bad lead. No burned insulators or springs or obvious arcing. Checked the logs, mags were oh'd 75 hrs ago, harness dates back to '84 and 700+ hours. Not too bad TIS wise, but some discoloration, some abrasion. Lot of heat under that LoPresti cowl. Yes, I could just replace the bad lead, but ignition being kind of important, starting fresh couldn't hurt. In the scheme of things not terribly expensive.

Which brings me to the question at hand. For Bendix s200 mags and Lyc O-540A1D5, Chief has a PMA'd Aero-lite harness at a fair if not good price, but it's a heck of a lot cheaper than Bendix or Champion. Does anyone have any experience or know anything about this brand? Any suggestions as to vendors for a new harness? Nobody local stocks them so it's your recommendation or the interwebs.

Thanks.
 
I've installed several of the Champion harnesses with good results. That would be my preference.
 
I've installed 2 Skytronics Aerolites harnesses with good results.
 
I have no problems with them.
 
I was seeing reductions in speed in my Comanche and seeing alot of ignition fouling in my IO-540. When I bought my 260 in 2006 I saw about 155ktas. That had reduced to 152-153 ktas through 2012.

At my 2012 annual we replaced 9 of the 12 plugs which passed the spark test but failed the resistance test. We also installed a new harness which was easily 20 years old.

When I picked up the airplane I was seeing 159-160tas to 9000 . . . and 155 from 9-11 and 153-154 over 11000. And not a single instance of lead fouling in the time since the annual. . . this was a 70% power at 2400rpm and WOT over 5000.

Was not due to lifting flaps or realigning the control surfaces - that had been done and had not been changed. . . .

The book on the airplane shows me 184mph [160kt] TAS @ 2500rpm and WOT. I'm seeing that at 70% or so and 162 at 75%. So I'm doing a little bit better than book . . .

PS Chip - I used one of the PMA's aero-lites in my IO540N1A5 - same engine essentially . . . Comanche, right?
 
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Just wrapped up and install myself on a musketeer Saturday. They seem fine to me. One thing I didn't like about them, was the lead length was quite a bit long and I had to do some creative routing to make it look nice. Other than that i'm sure they will work fine for you.
 
comanchepilot said:
I was seeing reductions in speed in my Comanche and seeing alot of ignition fouling in my IO-540. When I bought my 260 in 2006 I saw about 155ktas. That had reduced to 152-153 ktas through 2012.

At my 2012 annual we replaced 9 of the 12 plugs which passed the spark test but failed the resistance test. We also installed a new harness which was easily 20 years old.

When I picked up the airplane I was seeing 159-160tas to 9000 . . . and 155 from 9-11 and 153-154 over 11000. And not a single instance of lead fouling in the time since the annual. . . this was a 70% power at 2400rpm and WOT over 5000.

Was not due to lifting flaps or realigning the control surfaces - that had been done and had not been changed. . . .

The book on the airplane shows me 184mph [160kt] TAS @ 2500rpm and WOT. I'm seeing that at 70% or so and 162 at 75%. So I'm doing a little bit better than book . . .

PS Chip - I used one of the PMA's aero-lites in my IO540N1A5 - same engine essentially . . . Comanche, right?
Click to expand...

Yep. Carb'd though, not injected like yours.

Have you noticed any changes in cht's since you changed the harness? Mine's running a little hot, around 405 in cruise, oil temp 210, running 24/24 rop with the cowl flap trailing open about 30%. Baffles like new. Could be the combo of being down low (4-5k) and ridiculous oat's around here, and still within spec, but a little hotter than I like to see. Might just be life with the LoPresti cowl. That thing is tight.
 
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flyingmoose said:
Just wrapped up and install myself on a musketeer Saturday. They seem fine to me. One thing I didn't like about them, was the lead length was quite a bit long and I had to do some creative routing to make it look nice. Other than that i'm sure they will work fine for you.
Click to expand...


Lead length seems to be a bit hit and miss. This last harness I got was pretty much perfect tho.
 
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