New Coils For An Old ELTO

[huntleybill]

I tried the procedure Mr. Tubs describes on my Elto Rudder Twin and did not have much luck. I purchased this coil on ebay: Military Standard Engine Coil, Standard Ignition!!!! P/N: 9786E128. I wired everything up and tested it before I put it back into the brown cylinder. It worked great. I got spark at both plugs with my 6 volt battery. I then put it all together in the cylinder and filled it up with wax as Mr. Tubs demonstrates. After the wax cooled, I tested the assembly again and now I have no spark at all. I re-melted the wax and took it apart thinking that maybe a wire broke loose but that was not the case. Still no spark!

Also, with this coil, you can’t solder the spark plug wire on because whatever those two "nubs" are, they do not melt easily. They are not solder. I didn’t want to put a torch to it in fear of wrecking the coil. I used a zip tie to hold the wire onto the nub but not sure if that is the best way to do it.

Has anyone else tried this coil replacement? What coil did you use? How well did it work? Did you use wax to fill the cylinder or something else?

Your help is appreciated.
Bill

[wbeaton]

Bill, you can solder directly to the “nub”. First, you must clean the surface. I used a red Scotchbrite pad and a little carb cleaner to remove the thin layer of corrosion. Then using a Weller 125/250W soldering gun I soldered a drop of rosin core electrical solder to the surface of both spark plug wire terminals on the coil. Then I tinned the end of the spark plug wires. Finally, I soldered the tinned end of the spark plug wires to the terminal. Be careful not to overheat the coil when you tin the terminals. I took a resistance reading of the coil before and after soldering to ensure I hadn’t damaged the coil.

Wayne
Upper Canada Chapter

uccaomci.com

[huntleybill]

I did almost the same thing you described. I cleaned it, took out my old Weller my uncle gave me and tinned the spark plug wire but could not get the nub hot enough to get the solder to stick to it, Anyway, for some reason, the coil does not work now anyway. I need another coil. Which one did you use?

[wbeaton]

I used the same coil as you. I successfully did two of these conversions. I didn’t have any trouble soldering them after I cleaned the terminals. Perhaps our techniques were different. I started with a small puddle on my iron to help transfer the heat. It took a minute or so until the terminal came up to temperature. Have you taken a continuity reading of the coil to see if the windings changed? I think mine came out around 6 ohms or so. I don’t remember the exact number. If you coil is truly shot then you could practice soldering on it until you find the best way to make it stick. Maybe starting with an electronics flux will be necessary. Sorry I can’t be more help.

Also, don’t try to tin the wire directly to the coil without first having tinned both parts separately. You will have much better luck this way. Trying to tin both at the same time may result in too much heat at the terminal since the added mass of the wire draws heat from the puddle. I tinned the terminal first and then moved on to tinning the wire to allow the terminal to cool down. Once both parts are tinned they will be easy to stick together.

Wayne
Upper Canada Chapter

uccaomci.com

[The Boat House]

quote wbeaton:

. Maybe starting with an electronics flux will be necessary.

[huntleybill]

I used tinning flux. I will try again and see what happens.

[wbeaton]

Good luck, Huntleybill.

Wayne
Upper Canada Chapter

uccaomci.com

[huntleybill]

OK..I worked on the coil last night. It is definitely dead as I get no readings at all from the SP wire to any one of the smaller wires. I DO get continuity when I measure between the two small wires. So I ordered another coil. I also tried soldering again. I cleaned the nubs gently with my brass wire wheel (looks like those nubs are brass under that coating). I then, using flux, soldered the SP wire to the nub. I had to hold the iron on for a while before I could get it to "stick" but noted that the soldered connection is very brittle and breaks off quite easily. It is hard to solder brass. I re-tried soldering the wires holding the iron on the nub longer each time. I did finally get it to stick fairly well but the amount of heat used to accomplish scares me as I could small the plastic coating starting to melt. I am really concerned about that much heat being applied. Since you did a couple of these coils, am I worried about nothing??
What do you think? BTW…thank you for your advice with this.

Bill

[dave-bernard]

can you wrap the wire under the nub and solder the wire?

[huntleybill]

Sorry Dave. There is no "under" on this coil. BUT, I did try using my dremmel tool on the other nub and I cut a slit in the wide enough to allow the bare spark plug wire to recess in that slot. Then, using my hammer, gently tapped on the nub to close over the slit and wire. Now, I have no idea if cutting that slot ruins anything inside the coil as this coil is bad anyway.

Here is a link to te coil I am using so you can see what I mean: https://www.ebay.com/itm/2-SPARK-IGNITI … 2749.l2649

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