Resistor plugs & resistor wires?

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exhaustgases
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Re: Resistor plugs & resistor wires?

Post by exhaustgases » Fri Apr 13, 2018 9:02 pm

nitro2 wrote:
Fri Apr 13, 2018 6:41 pm
Air is an insulator. The more air you put in the gap the more voltage you need to jump the gap. The less air you put in the gap the less voltage you need to jump the gap. If you put enough air in the gap you can't jump it at all, the spark will just come out elsewhere.

Adding a resistor does not change the voltage requirement at all if there were no capacitance effects. A resistor does nothing until there is current, and technically there is no current until the gap is jumped, but in reality there is a little current due to capacitance.

The ignition system does not build voltage to overcome a spark gap AND overcome a resistor (unless there is significant capacitance) before firing the plug, it builds voltage to overcome the spark gap. Pulstar plugs are an example where the resistor does have a significant role because they purposely add a capacitor. On some applications Pulstar plugs work really well.
I agree some what, but a resistor is a current limiting device, it is like having a water hose squeezed at some point, and to try to get more water out of the hose the pressure (voltage) needs to go up.
Try it make a larger spark gap and the voltage will climb higher before it jumps. Air is an insulator, but it also does conduct depending on moisture.

"The more air you put in the gap the more voltage you need to jump the gap." Air pressure, Why is that?

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Re: Resistor plugs & resistor wires?

Post by MadBill » Fri Apr 13, 2018 9:59 pm

exhaustgases wrote:
Fri Apr 13, 2018 9:02 pm
...
"The more air you put in the gap the more voltage you need to jump the gap." Air pressure, Why is that?
Because compressed air is a better insulator than atmospheric.
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Re: Resistor plugs & resistor wires?

Post by Circlotron » Fri Apr 13, 2018 10:32 pm

exhaustgases wrote:
Fri Apr 13, 2018 9:02 pm
I agree some what, but a resistor is a current limiting device, it is like having a water hose squeezed at some point, and to try to get more water out of the hose the pressure (voltage) needs to go up.
That's true, but if the voltage is still rising and the spark has not yet begun then (ignoring capacitive effects mentioned by nitro2) no current has begun to flow so a resistor will have no effect. If the water in the hose has not begun to flow because the end is blocked off then any restriction in the hose will not affect the pressure (voltage) because there is no flow (current). Same as there is no pressure (voltage) drop across a throttle body if there is no airflow (current), even if the throttle (resistor) is 95% closed.

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Re: Resistor plugs & resistor wires?

Post by andyf » Fri Apr 13, 2018 11:52 pm

Your buddy might not need resistor plugs but it would be a good idea to double check the instructions for his MSD box before he makes a change. MSD boxes don't like solid core wires for example but I don't think the instructions say anything about resistor plugs.

Aftermarket EFI systems might not work with non-resistor plugs but it sounds like your buddy just has the MSD box and a carb. Caveman parts work with non-resistor plugs so he might be okay.
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Re: Resistor plugs & resistor wires?

Post by Geoff2 » Sat Apr 14, 2018 6:05 am

Also, the resistance of the leads is in series with the resistor [ if used ] in the spark plug & this combined resistance, which is also in series with the air gap, is only a fraction of the resistance across the air gap of the plug electrodes. So the resistance of the plug lead + plug resistor has negligible effect on the required voltage to ionise the gap in preparation for spark current to flow. Once current flows across the gap & voltage drops to ~1000-1100v, THEN the circuit resistance has a significant impact [ reduces current ].

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Re: Resistor plugs & resistor wires?

Post by Kevin Johnson » Sat Apr 14, 2018 8:20 am

A number of years ago I spoke with a customer who was an electrical engineer as well as a performance enthusiast. Her day job was to analyze circuit designs to ensure that the various components would not inadvertently interfere with one another due to proximity on the circuit board and so on.

Fast forward to the present where incredibly inexpensive accessory parts are offered for electronic equipment. Caveat emptor. A number of these products with not quite so much engineering will damage or allow damage to the parent device.

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Re: Resistor plugs & resistor wires?

Post by Kevin Johnson » Sat Apr 14, 2018 8:33 am

http://www.mtfca.com/cgi-bin/discus/board-profile.cgi?action=view_profile&profile=ndnchf-users wrote:Back in the day, Champion made a plug tester that has a pressurized chamber for testing plugs. It has a model T coil inside and connects to an air compressor. I have one and it works great. I set the pressure at around 55 lbs to test T plugs. The difference in spark is eye opening.
Champion 1.gif
Champion 2.gif
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Re: Resistor plugs & resistor wires?

Post by levisnteeshirt » Sat Apr 14, 2018 9:44 am

When MSD equipment first came out , they required no resistor plugs , no carbon core wires ,,, somebody became aware that it might effect over flying aircraft radio equipment and could have an associated liability there of ,, resistor plugs and carbon core wires required

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Re: Resistor plugs & resistor wires?

Post by psychomotors » Sat Apr 14, 2018 9:58 am

Kevin Johnson wrote:
Sat Apr 14, 2018 8:33 am
http://www.mtfca.com/cgi-bin/discus/board-profile.cgi?action=view_profile&profile=ndnchf-users wrote:Back in the day, Champion made a plug tester that has a pressurized chamber for testing plugs. It has a model T coil inside and connects to an air compressor. I have one and it works great. I set the pressure at around 55 lbs to test T plugs. The difference in spark is eye opening.
Champion 1.gifChampion 2.gif
Awesome. Would love to have one of these to play with.
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Re: Resistor plugs & resistor wires?

Post by Kevin Johnson » Sat Apr 14, 2018 10:18 am

levisnteeshirt wrote:
Sat Apr 14, 2018 9:44 am
When MSD equipment first came out , they required no resistor plugs , no carbon core wires ,,, somebody became aware that it might effect over flying aircraft radio equipment and could have an associated liability there of ,, resistor plugs and carbon core wires required
http://www.nybooks.com/articles/2000/09/21/swissair-111-twa-800-electromagnetic-interference/ wrote:The literature on electromagnetic interference is full of stories about unwanted electrical upsets that recur in the same space at the same time: one company, for example, found that its computers crashed every Friday at 3:00 PM; the cause turned out to be a piece of mowing equipment that was turned on at 3:00 PM each Friday during the summer. 12 12
Conversation with Ron Brewer, expert on EMC (electromagnetic compatibility) systems design, October 1998.
Just a thought -- there is a part of the population that wants to eliminate hot rodding or performance modified cars of any sort on the roads. There is a move now towards autonomous vehicles -- God help you if someone determined your EMI spewing vehicle was anywhere near a fatal accident involving one of them. Video cameras are everywhere now.

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Re: Resistor plugs & resistor wires?

Post by levisnteeshirt » Sat Apr 14, 2018 10:45 am

I know EMI occurs , I've saw it , I was an instrument tech in the Navy on control consoles for a remotely operated engineering plant ,, the fuel tank sensors acted like EMI antennas , they were long steel rods with magnetic switches inside of em to vary the resistance , the float acted on the switches ,,, anywaysss ,, just out of the blue ,, all of the panel meters for the fuel tanks would start going up and down ,, a certain position of a radar antenna , position of a radio antenna , the fix was to put an EMI filter on all of the inputs from the sensor in the tank ,,, note it was all shielded cable going to the sensors , all shielded for the whole system ,, some of which sent this energy to the ships ground , or to the isolated signal return for the internal ground of the control equipment, , we constantly had ghost alarms , alarms for equipment that wasn't even operating , , powerful extremely high wattage radar signals were on the ship , with also high inductive loads ,, ,, the frequency of an ignition system of a v8 engine is quite low compared to radar or radio ,, how much EMI created by a spark box to interfere with an over flying airplane seems fairly small to me ,, but electricity /magnetic fields doesn't care what anybody thinks , its a real world item , and it may not respond the same every time its created ,, the magnetic lines of force that surround the earth and your location to them could be the difference ,, Tesla was a genius , I wish he was here to chime in ,lol

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Re: Resistor plugs & resistor wires?

Post by Kevin Johnson » Sat Apr 14, 2018 11:01 am

Last year, during one of my many stays in the hospital, I shared a room with an older gentleman. He was there for the second time after being home for just one day due to his pacemaker misfiring multiple times in a row.

There is no privacy in these situations so I listened as his doctors told him about medicines and that they would try new ones. Finally I could not take it any longer and asked him if he would be willing to share more information about what happened to him and he agreed.

I asked for the model and serial number of his pacemaker which he carried with him in his wallet. I did research online and immediately found an article by EMTs that said this condition was found to be correlated with deteriorating lead wires. I asked him to describe what he was doing when this happened. He said he was watching TV. I asked him to describe the TV -- it was an old cathode ray tube model.

When I was discharged I visited him and saw that he was in a very cramped apartment and had been sitting smack in front of the TV, i.e, within a few feet. (I had previously told him to move as far away from it as possible.) I bought him a flat screen TV and told him to dump or give away the old set.

It was amazing to me to see in real life the consequences of people not paying attention during their science classes on their way to earning a medical degree, [-o< [-o< [-o< [-o< #-o

Aside: It is important to remember that the pacemaker had not misfired again in the several days that he was sharing the room with me. The doctors did not ask about that or seem to see any connection with where he was or what he was doing when the misfiring occurred. Sigh.

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Re: Resistor plugs & resistor wires?

Post by levisnteeshirt » Sat Apr 14, 2018 11:43 am

Television is very high frequency , good to hear you fixed him up

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Re: Resistor plugs & resistor wires?

Post by Kevin Johnson » Sat Apr 14, 2018 12:02 pm

People forget about crystal and "foxhole" radios; people hearing the radio from their fillings or other dental hardware. I am guessing that because of the internet and satellites being so prevalent (versus HAM and CB) people are much less "attuned" to learning about EMF and EMI. No excuse for lack of scientific analysis on the part of the doctor, though.

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Re: Resistor plugs & resistor wires?

Post by nitro2 » Sat Apr 14, 2018 1:37 pm

psychomotors wrote:
Sat Apr 14, 2018 9:58 am
Kevin Johnson wrote:
Sat Apr 14, 2018 8:33 am
http://www.mtfca.com/cgi-bin/discus/board-profile.cgi?action=view_profile&profile=ndnchf-users wrote:Back in the day, Champion made a plug tester that has a pressurized chamber for testing plugs. It has a model T coil inside and connects to an air compressor. I have one and it works great. I set the pressure at around 55 lbs to test T plugs. The difference in spark is eye opening.
Champion 1.gifChampion 2.gif
Awesome. Would love to have one of these to play with.
We built one for in-house use, it goes to 2000 psi. Has a thick window. It has been used for several years now to good advantage.

We use it to test spark plugs, test sensors, test spark plugs with sensors. All sorts of plugs have been run on it, as well as ones we have modified to see what the effects of doing this or that would be.

We have learned lots, but I dare say there is more to learn yet. Like most things, the more you learn the more you realize that you are a long ways from knowing it all lol.
TFX Engine Technology Inc.
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www.tfxengine.com
1-800-479-5571

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