Spark Plug Wires

[D&J Edgar]

A TC spark plug has a gap of .020-.022 to start with anyway, but can open up some as it wears.  But even worn, that is a fairly small gap and 20,000 volts can jump it easy.  Add combustion chamber pressures and it will change some but still fairly easy to jump.   As far as resistance in plug wires, the resistance really only shortens the spark duration.  There is much, much more resistance to jump the gap and once the spark occurs the wire resistance just shortens the duration a little.  You really do not need a long duration as once the mixture is ignited, a longer spark is doing nothing as the flame front has moved well away from the plug at the end of the spark duration. So why do you need to jump up to a 30K coil if the spark will jump at below 20K?  If say the spark did jump at say 15K, then you would get a longer spark, but as I said above, once the mixture ignites, the added spark does nothing as the flame front is already moved away from the plug.  But I guess I should add that a longer spark duration will wear your plugs faster.  If your XPAG is hopped up, it will still be mild compared to modern engines, but 30K coils do allow you more margin of error.  But I think a XPAG that is well maintained will work fine with 20K as many do.  Just my opinion.  Should note the plugs seem to last longer and stay cleaner with the unleaded fuel we have now.  Way back, when we ran the leaded stuff, plugs needed more maintenance and if they got worn and dirty you might be getting close to needing the extra voltage.  Old HT plug wire would break down too.   I happen to have a 30K Lucas Sport coil on my TC because I needed a new coil some 25 years ago and that one looked good for about the same price.  I put on modern 7mm silicone plug wires with carbon impregnated conductor at the same time and have had absolutely no problems whatsoever and I do push my TC.  I know the silicone wires do not look original but I rather drive than deal with doing repairs. David Edgar, TC 5108 El Cajon, California

[Alex]

[b]Copper core high quality do-it-yourself ignition sets from Tractor Supply. [/b] [b][/b]  [b]$19.95 for a 6-cylinder set, including all boots, etc.[/b] [b][/b]  [b]== Alex in Maine [i]     "The Blue Mainie," 1960 Austin Healey 3000 BT7      "Conkling," 1946 M.G. TC #1321      Former owner 1957 A-H 100-6, 1967 A-H BJ8,      1965 MG Midget   ( )      [/i][i]http://ai2q.org/[/i][/b] [b][/b]  [b][/b]  [b][/b] 

----- Original Message ----- [b]From:[/b] jvvmusme@yahoo.com [mg-tabc] [b]To:[/b] mail@mgnuts.com [b]Cc:[/b] MG-tabc@yahoogroups.com [b]Sent:[/b] Wednesday, September 16, 2015 2:37 PM [b]Subject:[/b] Re: [mg-tabc] Spark Plug Wires   Bumble bee Sent from my iPhone On 16/09/2015, at 1:19 p.m., "Steve S mail@mgnuts.com [mg-tabc]" mg-tabc-noreply@yahoogroups.com> wrote:   What is the group's opinion on the best plug wires and connectors to use on the TC? I'm running the stock type setup (Packard stranded wires with Lucas connectors) which has been just fine up to now, but with a few performance enhancements I'd like to try something different to gauge any difference in high-speed running. Moss lists their standard wire (basically what I'm running now) and Bumblebee wire which doesn't list any specs but I suspect it's the same non-shielded copper wire. - Steve Simmons, TC8975

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