Plug wires for electronic ignition

[Humdog]

I'm a new member and owner of a 57 BN4 100-6 Longbridge. I just put pertronix in my car. My distributor is a DM6 with a side entry cap. I have Bubble Bee wires now but have been told they are not good for the electronic ignition. Does anyone have any suggestions for different compatible wires I could use?

 

[Guest]

Your well meaning source was mistaken! Those wires won't hurt anything. Run with them... further questions? call me. 713-503-3909

 

[AUSMHLY]

From this forum, I have read questions about if it is better to run carbon wires when a pertronics ignition is intalled in our Healeys.

Carbon vs copper. Anyone?

When I installed the pertronics, I replaced the coil with a Lucas sports coil.
I'm not sure if my stock coil was going defective or if the Pertronics needed more volts. The car ran much better after installing the Lucas sports coil.

 

[GregW]

Hi Humdog,
If you have the stock dizzy, you should stick with the bumble bees. Carbon/silk wires won't work for long with a screw type cap.

 

[steveg]

For metal vs carbon wires info, suggest you call Pertronix in San Dimas CA or look on their website. I've called them a couple of times and they've always been helpful. They were the ones who told me a bad coil can fry their unit.

I'm running metal wires from Healey Surgeons with a neg ground Pertronix and Pertronix' own non-ballasted coil.

I had an Auto Zone coil go out and eat the Pertronix so this time I figured if their coil went out I'd have recourse with them for both pieces.

 

[AUSMHLY]

Hey Steve,
Sound like you're comfortable with the Pertronix ignition and coil. Why are you not running their (carbon)wires? Just curious.

 

[tahoe healey]

Any issues with static on the radio with different type wires?

 

[Humdog]

Hey everyone,
Thanks for the imput. I did call Petronix about the Bumble Bee wires and they said if the wires are new it should be OK however they recommend the carbon wires. I like the stock look of the side entry cap but would be willing to use a top entry cap if I could find one for the DM6 distributor. Petronix also does't make a set of wires for a 6 cyclinder Healey. I just don't want to srew up the ignition.

 

[Ed_K]

Hi Tahoe,
To answer your question about radio noise; Yes, there is a big
difference in radio noise with the types of wire used;
Maximum radio noise= Standard Metal wires, (stranded or solid core).
... The standard metal wires act like little radio transmitter antennas. The higher voltage coil you have equates to a stronger " transmission " from the wires.
... When standard metal wires are used, there is no limitation
on the current flow through the distributor cap, rotor, and ignition wires thus a strong transmission of noise from the ignition wires that reaches your radio, ( am, fm, and it is strong enough to make noise when playing CDs or MP3 players).
... Both carbon core ignition wires and wound metal core wires
inhibit maximum current flow and thus eliminate electrical noise transmission from your ignition system.
Because of the greater current flow through standard core wires, the POTENTIAL for damaging an electronic ignition sensor is greater since there is more current flowing through the coil than if carbon or wound wire ( looks like a long spring inside of the insulation if you could see it ). That doesn't mean using solid wires will cause the petronix failure, but if a weakness in the hall effect transistor develops over time, then the big current is available to " finish it off in a hurry ". This won't happen as quickly with carbon or wound wire ignition wires.
.... That's probably more than you wanted to know. I apologize.
... My recommendation is Magnacore ignition wires. They sell three different sets for our 6 cylinder Healeys. One set is black colored and will install into the standard side entry distributor cap ( 7 mm ). I use the red 8mm wires into a top entry distributor cap.
This is a lot like recommending the best motor oil. I am certain there will be many other opinions about this. Carbon wires don't last as long as these type of wires but will also work well until the carbon starts to break down from the heat inside of the engine compartment. And Dave has correctly pointed out in the past that if you simply replace the wire that goes from the coil to the distbutor cap with a type that limits current, then you can still use the solid core wires from the distributor cap to each spark plug as the coil wire will limit the current flow to each spark plug.
Others opinions will vary !
Ed

 

[GregW]

Because of the greater current flow through standard core wires, the POTENTIAL for damaging an electronic ignition sensor is greater since there is more current flowing through the coil than if carbon or wound wire ( looks like a long spring inside of the insulation if you could see it ). That doesn't mean using solid wires will cause the petronix failure, but if a weakness in the hall effect transistor develops over time, then the big current is available to " finish it off in a hurry ". This won't happen as quickly with carbon or wound wire ignition wires.

Hi Ed,
You lost me there. Aren't the plug wires downstream of the Pertronix? There isn't any higher voltage or current flowing through the distributor except in the cap and rotor. The Pertronix (or points) just charge and collapse the coil field with 12 volts. :confuse:

 

[Ed_K]

Hi Greg,
I am thinking Energy out = energy into the coil.
If you limit the current output of the coil during spark discharge, then the input pulse on the 12 volt side of the coil has to be a shorter duration thus less cumulative energy being run through the hall effect transistor. If a breakdown starts to happen in the junction of the hall effect transistor, then any extra energy will hasten the time to complete failure.
... I may be wrong ...
The other hall effect transistors that I have experience with last around 7 years of continuous use at 5 volts. I don't think that the type of ignition wires in use could possibly hurt the Petronix in our lifetimes. If they fail, they were simply defective when they were manufactured. But if someone asks a theroretical question about " which is better " for longer life, it is always the circut that contains less energy.
.... Or I could be just full of sh-- !
Ed

...

 

[GregW]

Hi Ed,
The way I understand it is the coil would cycle the same. 0-20,000 volts (or whatever) while the points are closed. As the points open, the field between the primary and secondary coils collapses and discharges the high voltage, down to zero. The resistance in the wires or plugs would dissipate the energy as heat.

 

[Ed_K]

You are right, it would cycle the same and the output voltage and input voltages should be constant. So if there is less current in the output, there has to be less current or a shorter duration pulse width in the input.

 

[Ed_K]

Maybe I can bring a scope home from work and see what is happening on the primary side, then swap in my original distributor cap and solid core wires and then check it again to see what the real difference is.

 

[GregW]

The only scope I have is in the bathroom cabinet.

 

[Stretch]

I think the electrical stress on the primary circuit is more related to the inductance and resistance of the primary circuit. The current on the secondary side is a result of the peak voltage developed by sharply interrupting the primary current divided by the secondary side resistance. Interrupting current in an inductor (coil) causes a very high voltage spike that reaches the 40K+ voltage on the secondary side of the coil. There's a bunch of electrical factors at play here. An engine's ignition system is really a quite clever but simple use of electrical principles. I'd be very curious to hear the results of the suggested test.

 

[healeynut]

Humdog -

The top entry cap for the TR6 is interchangeable with the BJ8 dizzy. I don't know about the earlier healeys....

Best Regards,

Alan

 

[Guest]

One exception to that theory... waste spark ignition. The coil fires 2 plugs at the same time making them a part of a closed "loop" circuit whereby the 2 plug gaps are polarized opposite one another.... on one plug, the spark goes from the center electode through the body of the plug to ground.... then that energy transfers throug ground, across the second plug's air gap, into the center electrode, and back to the coil. This type system is vulnerable to backfeed if a plug gap gets too wide, a wire goes high resistance or comes off, etc. This backfeed can destroy the primary side module, and in the case of Chrysler, blow the ECM. But, the old fashioned ignition system does't have that potential to ruin the primary side of the ignition. Most LBC's have high ground potential in their ground circuit...this is easy to diagnose.... start the car, take a DVOM and set it to 12V. scale. put the leads across the engine and ground side of the battery.... it doesn't matter if you have positive ground. Read the voltage displayed on the meter... if it is over 200 mV, you have a problem... usually cured by installing a shunt ground from battery earth to the car's sheet metal or from the block to body. You've no idea how many vehicles I've fixed in my shop with this simple problem... both vintage and modern. I bought an F-150 years ago where the guy had spent a lot of time and money rebuilding the engine, but could not get it running well enough to pass emissions.. Tired of fussing with it, he sold the Truck to me for a song. I found the ground strap that goes from the body sheet metal to the engine dangling loose... he had neglected to re-connect it when he installed the engine. I hooked it up and she passed emissions with no problem... I drove that truck all over Texas for a couple of years and sold it.

 

[Humdog]

Thanks again for all the feed back. I got an email from Moss about plug wires that they stock but are not listed. The part number is HP901 for $53.95 for the set, incase anyone else is interested. They are a modern style resistor wire normally intended for a push on cap but the ends can be cut off to fit the side entry cap. Moss' customer service has been a great help as well.