N8RV
Well Known Member
Another thread discussed the importance of having good, solid connections from the coax to the coils if you have a Lightspeed Engineering EI unit, which turned out to be an issue for me recently.
I had just returned from escorting the RV-1 to Lee's Summit and landed uneventfully. Put Smokey to bed without even cleaning off the bugs. I went out on Thursday for a quick flight around the patch (and clean off the bugs afterward, naturally) and was quite surprised when I did my run-up to find that the engine power dropped very dramatically when I turned off my left mag and ran on the LSE only.
I taxied back and pulled the cowling to change the oil and cogitate what could possibly have caused the lack of power. After all, LSE had just repaired and updated my Plasma II+ unit about 50 hours ago.
After changing the oil and filter, I started with the LSE unit and worked toward the engine. All seemed fine until I got to the connection of the coax to the coil -- the center wire was broken! Broke right at the crimp connector.
I stripped the center lead and crimped on a new connector. I decided to check the other connector as well and did no more than just touch the lead and the wire broke!
I had routed the coax around the center baffle support bracket to the right, then looped it back behind the coils, making a pretty sharp curve with the coax. There is obviously enough vibration when the engine shakes to have fatigued the center conductors where the connectors are crimped. I have reinforced the connector area with some sensor-safe RTV until condition inspection. Then I will re-route the coax cables and bring them DIRECTLY through the baffle and into the coils with no curves.
As a first-time builder, these are the kinds of things that are not second nature. With something as critical as electronic ignition systems, having a wire break due to vibration is not a good way to learn. Take a look at your installation -- if your coax cables make bends anywhere near the connectors that plug into the coils, you would be wise to either re-route the cables to eliminate the bends or reinforce and support the coax-connector interface.
Hope that makes sense. I didn't think to take any pics of my installation or the problem might have been evident to an experienced builder.
I had just returned from escorting the RV-1 to Lee's Summit and landed uneventfully. Put Smokey to bed without even cleaning off the bugs. I went out on Thursday for a quick flight around the patch (and clean off the bugs afterward, naturally) and was quite surprised when I did my run-up to find that the engine power dropped very dramatically when I turned off my left mag and ran on the LSE only.
I taxied back and pulled the cowling to change the oil and cogitate what could possibly have caused the lack of power. After all, LSE had just repaired and updated my Plasma II+ unit about 50 hours ago.
After changing the oil and filter, I started with the LSE unit and worked toward the engine. All seemed fine until I got to the connection of the coax to the coil -- the center wire was broken! Broke right at the crimp connector.
I stripped the center lead and crimped on a new connector. I decided to check the other connector as well and did no more than just touch the lead and the wire broke!
I had routed the coax around the center baffle support bracket to the right, then looped it back behind the coils, making a pretty sharp curve with the coax. There is obviously enough vibration when the engine shakes to have fatigued the center conductors where the connectors are crimped. I have reinforced the connector area with some sensor-safe RTV until condition inspection. Then I will re-route the coax cables and bring them DIRECTLY through the baffle and into the coils with no curves.
As a first-time builder, these are the kinds of things that are not second nature. With something as critical as electronic ignition systems, having a wire break due to vibration is not a good way to learn. Take a look at your installation -- if your coax cables make bends anywhere near the connectors that plug into the coils, you would be wise to either re-route the cables to eliminate the bends or reinforce and support the coax-connector interface.
Hope that makes sense. I didn't think to take any pics of my installation or the problem might have been evident to an experienced builder.