WPVT Posted October 10, 2020 Share Posted October 10, 2020 While adjusting the timing on my 1954 Dodge flathead, I got a reasonably good shock from the side of the distributor cap. I can also get a shock from touching the ignition wires (brand new cloth covered solid copper). Is this normal ? If so, seems like it would be easy for cross-firing to take place since the wires are routed in close proximity to each other. Link to comment Share on other sites More sharing options...
Guest Posted October 10, 2020 Share Posted October 10, 2020 That should NOT happen. You have secondary current leaking out somewhere. NOW all you need to do is find the leak or leaks.. Link to comment Share on other sites More sharing options...
WPVT Posted October 10, 2020 Author Share Posted October 10, 2020 (edited) Thanks. Could you give me an example of this kind of leakage ? I don't quite follow. If I feel a shock, isn't the current just leaking to me (a ground) ? Edited October 10, 2020 by WPVT (see edit history) Link to comment Share on other sites More sharing options...
padgett Posted October 10, 2020 Share Posted October 10, 2020 Were you perspiring ? Rubber soled shoes are a good thing. Link to comment Share on other sites More sharing options...
WPVT Posted October 10, 2020 Author Share Posted October 10, 2020 My question is if it is normal for new cloth covered wires to give me a shock could they also arc between each other easily and cause problems when the engine is running ? They travel through a steel cover fairly close to each other. I just read where if you get a shock when you touch them, then the wires are no good. But these are brand new. Perhaps this is a difference between carbon wires and copper. Link to comment Share on other sites More sharing options...
Str8-8-Dave Posted October 10, 2020 Share Posted October 10, 2020 It's not normal for you to be getting a shock. Most repro cloth covered wires have a rubber core that should contain the spark. If you got shocked then yes cross firing is possible. Try making a ground probe consisting of any screwdriver with a plastic handle that totally isolates your hand from the shaft and blade and connect a3 ft piece of 14 gauge insulated wire to the shaft and put an alligator clip on the other end of the wire. Clip the alligator clip on a ground on the engine and probe around the cap and wires to see where the leaks are and fix them. Do it at night if you don't find anything obvious in daylight, have an assistant turn the lights off in the garage but don't get your fingers in the fan... 3 Link to comment Share on other sites More sharing options...
Bud Tierney Posted October 10, 2020 Share Posted October 10, 2020 Concur should not feel anything from cap or wires... Same shock from wires as from cap, or lesser?? If wire shock from just one wire check connection area for the crack... Suspect tiny crack in cap (assuming its pristine clean in and out) and current travelling wire or wires, which should not happen itself...anything spilled on wires before/during installation that could be conductor?? Link to comment Share on other sites More sharing options...
vermontboy Posted October 10, 2020 Share Posted October 10, 2020 Perhaps a cracked cap or bad wires - as noted above make certain that the core is covered with rubber material before the cloth was applied.... If it was mine and not subject to judging I'd get a new cap and make a set of wires from Packard 440 wire .... Link to comment Share on other sites More sharing options...
WPVT Posted October 10, 2020 Author Share Posted October 10, 2020 (edited) It's a brand new cap. If I grab it and rotate it to adjust the timing, I get a little shock. Not huge. Everything's clean as a whistle. I'll try the wires again this morning and report back. They were good quality. I bought solid copper, vintage style, rather than carbon from the auto parts store, thinking it was an upgrade. Edited October 10, 2020 by WPVT (see edit history) Link to comment Share on other sites More sharing options...
Rusty_OToole Posted October 10, 2020 Share Posted October 10, 2020 They went to carbon core wires to suppress radio noise. No difference in performance. You should add a radio suppression capacitor or just use a carbon core coil wire with the copper plug wires. 1 Link to comment Share on other sites More sharing options...
Bloo Posted October 10, 2020 Share Posted October 10, 2020 (edited) Not an upgrade but not a downgrade either. Running the wires parallel, or through steel parts of any kind is asking for trouble. Buick for instance got away with it for years but that does not make it a good idea. If you are having driveability problems, I suggest running without steel covers or looms until you get it sorted and THEN put the wires back in them. Make sure the wires are tied out of harms way in the mean time. You can get shocked getting close to a good wire, but probably not that much. I make it a point to avoid them. If energy is jumping through the insulation, and the insulation is not damaged, the problem is likely that the voltage is too high. The resistance of all wires and parts between the coil tower and the plug set the voltage level. I know that's counterintuitive, but it's true. Check all wires with an ohmmeter (a cheap DMM works). Resistance should be really low on solid wires. On carbon, maybe a few Kohm, with the longer ones being higher than the short ones. Also check that the carbon button in the cap is present, and make sure it is touching the rotor. It might be spring loaded, or the rotor could have a spring steel blade that touches it. Whatever it has, make sure the two touch and there is not a gap. If there is a resistor in the rotor, check it with the ohmmeter too (center to tip). A few Kohm at most, and you probably will just have solid metal and not a resistor on an antique. Gap your plugs. If you are getting shocked by the distributor, check that it is well grounded to the block, and look the cap over real good for cracks and carbon tracks. Edited October 10, 2020 by Bloo (see edit history) 2 Link to comment Share on other sites More sharing options...
Rusty_OToole Posted October 12, 2020 Share Posted October 12, 2020 Are you using resistance plugs? Gapped too wide? Too much resistance can cause the problem you describe. Link to comment Share on other sites More sharing options...
WPVT Posted October 12, 2020 Author Share Posted October 12, 2020 Thanks Rusty. Just regular plugs. This isn't a big problem, just something I noticed and was curious about, especially as the wires travel through a steel cover where they are in close proximity to each other. But the engine runs OK without misfiring. Link to comment Share on other sites More sharing options...
zepher Posted October 12, 2020 Share Posted October 12, 2020 Check your ignition system in the dark, as Str8-8-Dave suggested. If you see fireworks then you know you have ignition voltage leaking. Just start the car, pop the hood and take a look. 1 Link to comment Share on other sites More sharing options...
60FlatTop Posted October 12, 2020 Share Posted October 12, 2020 If you are far enough out in the sticks you might find a shop that would put an oscilloscope on it and find the problem You might find a refrigeration mechanic who would clip a Megger (megohmmeter to the coil end of the coil wire and see if you can make an arch. Link to comment Share on other sites More sharing options...
ojh Posted October 12, 2020 Share Posted October 12, 2020 I wonder why you are only getting a 'little shock'? Link to comment Share on other sites More sharing options...
54vicky Posted October 15, 2020 Share Posted October 15, 2020 On 10/12/2020 at 3:39 PM, ojh said: I wonder why you are only getting a 'little shock'? that is a relative term it means different thing to each person Link to comment Share on other sites More sharing options...
John_Mereness Posted October 15, 2020 Share Posted October 15, 2020 I have had new cloth braided ignition wire right out of the box from being delivered fail - I assume some kind of manufacturing flaw in the coating as technically they are braiding over modern wire and should be even more isolated. Link to comment Share on other sites More sharing options...
WPVT Posted October 15, 2020 Author Share Posted October 15, 2020 Thanks to all. From what I can tell, the small amount of electrical shock I received was normal. The truck runs well and does not show signs of misfiring due to leakage in the high voltage system. Link to comment Share on other sites More sharing options...
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