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MG MGB Technical - Resistor plugs or not

Hi all,
I'm switching to NGK plugs,should I install resistor type plugs or the standard BP-6ES?, my ignition system use silicon resistor wires.
Thank you,
Barry 72B
B Shnabel

Barry. I have never seen any difference in practical usage. Les
Les Bengtson

Barry - If you have resistance wires, do not use resistor plugs. One or the other, but not both. Cheers - Dave
David DuBois

I hesitate to differ from Dave but at http://www.ngkntk.co.uk/technicaltips/resistorplugs.asp NGK quotes "As well as reducing electrical noise for radio, television and mobile telephones etc, many modern ignition systems require resistor plugs to stop electrical noise from interfering with the vehicle's on-board electronic control units (ECUs). If non-resistor plugs are used in place of resistor ones, the result can be malfunction and in some cases immobilisation of the vehicle."

It goes on to say that apart from some very old low-output ignition systems resistor plugs can be used in place of non-resistor plus without any problems.
Paul Hunt

Barry-
The purpose of resistor spark plugs is the supression of electromagnetic pulses from the ignition system. Unfortunately, they do this at the price of decreasing spark energy. Resistor spark plug leads (wires) acomplish the exact same thing. If you put the two together, then the spark will be further weakened. As David said, use one or the other, but not both. I also use silicone leads (wires) with ordinary spark plus (no resistors) and have no problem with electromagnetic pulses creating interference with my car's radio.
Steve S.

My experience with restance wires and resistor plugs was exactly as explained by Steve, when I used the two together, I started experiencing missing that doesn't occure if one or the other is usec alone. I have to agree with Paul, that some form of Electrical Magnetic Interfeerence suppression should be used in the car. Not only does it eliminate static in ones radio, the EMI could cause a problem with electronic ignitions (if they are computer driven). For those ou you with conventional points style ingnition and either no radio or run (like I do most of the time) with the radio off, you still need to use some sort of EMI suppression in consideration for your fellow moterist. It is quite anoying to stop at a signal next to an old car and have your radio reception suddenly go all scratchy (right up there with being next to one of the THUMP, THUMP, THUMP jerks. Cheers - Dave
David DuBois

Thank you all, I find it hard to get standard BP-6ES plugs here, my car has a pertronix ignition + 40k coil, will a resistor plug work ok ? Cheers, Barry
B Shnabel

They will probably work but you are driving up the voltage in the ignition secondary and this increases the chances of failure of the coil tower, cap, rotor, spark plug, etc.
Leland Bradley

Barry - Go ahead and use the resistor plugs and if you start getting unexplained missing, just replace the resistance wires with plain wires and you should be ok.
Good luck - Dave
David DuBois

Thank you all, Cheers-Barry
B Shnabel

This thread was discussed between 19/03/2004 and 20/03/2004

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