Graphite Vs Copper Spark Plug Wires

Hello,
This is a continuation of the ford 4000 spit and sputter thread. Anyway, I replaced the plug wires on the Ford 4000 with graphite wires and installed new plugs last year figuring I would eventually want to put in Electronic ignition. I looked into the electronic ignition today and watched the Steiner video about same. During the video the statement was made that you should not use Graphite wires with standard ignition. So that got me thinking if I may have caused the spit and sputter issue because of the upgrade to the so called better wires. So the question is could the graphite wires cause poor performance when installed on standard ignition?



Thanks,

JohnB
Spit & Sputter Link

The resistor wires will be fine. Look elsewhere for the source of your problems.

In my opinion no... that said if all else ignition, timing, fuel mixture and engine is mechanically sound. Millions of autos from probably the 50?s through 1974 or there abouts came off the assembly line with Kettering ignitions and radio static suppressing graphite spark plug wires. And they probably logged billions of miles with minimal issues other than there replacement when they went bad. I should go back and look up a post I made on this topic a year or two back and post a link to it. Now let the electrical gurus rain it down!

Thanks for the fast responses, really Appreciate it.

John B

Resistor wires will work fine with distributor ignition, as discussed look elsewhere.

To your question "So the question is could the graphite wires cause poor performance when installed on standard ignition?"

ANSWER Probably NOT in my humble opinion, but not being there or armed with any actual testing or specs or data no warranty...

Yearsssssssssssss ago early cars used wire core plug wires,,,,,,,,,,,Then to reduce radio noise interference along with other advancements carbon core suppressor wires were used for yearsssssssssssssss NO PROBLEMS

NOTE 1 In older tractors that used Magneto Ignitions wire core wires were originally used, and to this day I recommend their use over carbon core.

NOTE 2 In todays possibly higher voltage higher energy tractor replacement electronic ignition systems, such as some of the Pertronix units, some degree and type of suppressor wires are actually recommended versus wire core plug wires.

Since your Ford isn't a Magneto Ignition and not any Pertronix type after market ignition, ITS MY OPINION CARBON CORE WIRES (provided good quality) ISN'T A MAJOR CONCERN. Maybe a new plug wire had a problem or it was a cap or rotor or distributor issue ??

John T

Those Carbon wires are fine. They should measure about 7 to 8,000 ohms per foot of "wire".
A High Voltage wire not mentioned in this thread yet is magnetic suppression wires. These have a spiral wrap of fine real copper wire around a central core of kevlar or glass fiber. They have very low resistance, and very low radio static emissions. They work in all systems but are expensive. Jim

I find these comments a lot like putting a high tension coil on a low compression engine. The spark will only need as much voltage to jump the gap, and it will only use the amount of current required to create the voltage based on the resistance.

Too many people overthink this.

Yo Professor Jim, correct me if I'm wrong, but I believe those type of wires in part serve the purpose of reducing RFI or radiation which might possibly interfere with some of the electronics in an electronic ignition control system. Seems like I read that about Pertronix ??

John T More into AC, power, and old tractor DC electricals then modern electronics, Im too old for that, I still studied Vacuum Tubes at Purdue in the sixties lol

I agree David. Some of the non sparkies don't realize the voltage across a spark plug gap ramps up and ONLY rises high enough until current arc jumps the gap NO MORE. That necessary voltage is a function of the gap distance and the medium (fuel and compression) in which it fires. Just because a person uses a so called HIGH VOLTAGE COIL given the same conditions (gap and fuel and compression) it wont fire at any higher then the old stock coil ITS JUST THAT IT HAS THE CAPACITY TO ACHIEVE A HIGHER VOLTAGE IF REQUIRED like a wider pug gap or different fuels or compression.

A pleasure sparky chatting with you

John T

Either wires would be alright for an old tractor with points. The graphite wires become more necessary on newer engines with electronic ignition. The copper wires tend to burn out the electronics on modern systems.

Good old 12AX7, 50C5, or 5U4. Tough to beat thermionic emissions. The windings on the synthetic core both conduct, and suppress RFI by being a inductive choke with properties in the Broadcast bands. conductivity is usually in the range of 10 to 200 Ohms/ft. Jim

I haven't changed from points and condenser. Electronic ignition products a higher voltage spark. My 2007 GMC has high voltage spark and distributor cap. Most cars ave distributorless ignition now. IMHO and from replacing the distributor cap and rotate on truck about every 2 years, I think the old caps can't hold up to the higher voltages.
I wouldn't change over the electronic ignition. I grew up with points and condenser, I can easily replace them. No biggie.
George

Interesting topic. The spark voltage across the plug gap is the sole determining factor of spark voltage. The compression and density of the combustion pressure changes that voltage, but the amount of spark intensity and duration can be affected by the type of switch (read points, or electronic device). Advantage electronic. Jim

Remember years ago when our televisions got the signal from an antenna cars or tractors with solid copper plug wires would make static on the TV? Two banger Deeres would make a slow rhythmic static but the neighbor who drove by in his Buick straight eight made a flurry of static.

With points and condenser copper wire will always work,so why take a chance on some Chinese junk for plug wires?

George just to help you and provide you with a bit of information, with ALL DUE RESPECT regarding your statement:

"Electronic ignition products a higher voltage spark."

FYI the voltage required to cause current to arc jump across the spark plug gap IS A FUNCTION OF THE GAP DISTANCE AND THE MEDIUM (fuel and compression) in which it occurs. Its (spark voltage) NOT based on if its an elec switch or mechanical points switching the coil current on and off........An electronic ignition alone (versus points) does NOT produce a higher voltage spark !!!!!!!!! GIVEN THE SAME CONDITIONS the firing voltage using an elec switch would be near the same as points

1) And that's the same REGARDLESS if an electronic ignition or mechanical contact points makes and breaks the coil current

2) An electronic ignition (same as points) DOES NOT produce a higher spark voltage then necessary to arc jump current across the plug gap.

3) REGARDLESS if points make and break the coil current orrrrrrrrr a solid state device given the same conditions (plug gap and fuel and compression) THE FIRING VOLTAGE IS APPROXIMATELY THE SAME

Typically in late model cars with elec ignitions versus old low compression tractors, the spark plug gap may be wider in which case the firing voltage must necessarily be higher BUT THAT'S NOT CAUSED BY ELEC IGNITION (even with points the firing voltage would have to be higher if the gap is wider) ITS CAUSED BY A WIDER PLUG GAP!!!


As an electrical engineer and past farmer and old tractor dealer HEY I LIKE THE OLD POINTS SYSTEM AS WELL AS OTHERS but its an engineering reality that the modern elec ignition systems SO LONG AS THEY ARE WORKING are superior to using a set of mechanical, ever burning, ever corroding, ever increasing resistance, bouncing, ringing points to make and break coil current................WELL DUH

NOTICE I'm NOT arguing or advocating points versus elec ignition, do as yall please I AM STATING WHAT I BELIEVE TO BE ENGINEERING FACTS

I'm NOT advising anyone to change over from points, when I used and bought and sold old tractors I didn't change them from
points to elec ignition

I like points in old tractors and use them BUT I WOULD NOT CHANGE MY NEW CAR BACK OVER TO POINTS. There can be advantages as well as disadvantages to BOTH so TO EACH THEIR OWN PREFERENCES

Hope this helps your understanding (Hey I'm with you, WE AGREE, I didn't change any of my old tractors over either)

Take care n be safe Good Neighbor

John T

a single coil system..... early hybrid electronic ignitions had ""dwell extender" circuits in them via amplifying the points signal to a higher current device thus allowing the coil to charge to a higher magnetic field thus storing more potential energy for each fire cycle. And they also buffered the points to a very low current so that they did not burn. We used to build them for our race cars in the late 60s early 70s... HeathKit made one that used a multivibrator to create the higher voltage fed to the coil. This model had a bypass switch so you could run it in bypass mode or in amplifier mode. Switching it from off to on on a carbureted engine you would see a 200 rpm increase at an idle from the longer firing time, creating better and more complete combustion. You could open the plug gap up from .035 to .040 to see more improvement. Ironically, a conventional points system on a single coil, worked at less efficiency, where a magneto worked better as rpms increase. So the early dwell extender modules fixed this problem somewhat. Later the hall effect transducers eliminated the points totally so the wear, conductivity, and moisture problems were removed from the equation. Then emissions drove the high voltage systems coils that better fired off the combustion cycle and made the previous redundant. Later by using a coil for each cyl gave the engineers more control with variable timing, ability to fire every other cyl, and solve the coil charge time (at high rpms) problem as well. Now a coil only had to fire one cyl instead of 8 cyls....This also ,as other have said, removed the distributor, and its associated problems. This allowed the ecu to map the timing all over the place with different logic than just rpm... ie deceleration, overheating, ping sensors, maps for differernt gears, modes etc. Throw in variable cam timing, and variable fuel injection control and you can do the impossible.

I glanced over the spit and sputter thread, and while I don't think the wires were necessarily the problem, I have seen the graphite core wires cause problems on tractors with points and I always use either the stranded wire core or spiral core wires.

I think the problem is that it seems to be nearly impossible to find decent quality graphite core replacement wires rather than being a problem with the concept of a graphite core. Sometimes too there are other weak areas that the graphite wires exacerbate due to their higher internal resistance. Graphite core wires run 8- 10 thousands ohms resistance vs. practically zero for wire core. That resistance is going to encourage leakage elsewhere while it's building up to fire the spark gap. Throw in a weak distributor cap or some dampness for instance and your voltage may find an easier path to ground than where you wanted it.

My most recent experience with those wires was automotive rather than tractor. A couple years ago I bought a C30 Chevy with a TBI 454. I drove it home but it didn't run right. Mostly in good shape, some unknown re-man motor under the hood. The PO had, in the previous couple of months, put on a brand new set of parts store wires, graphite core. In my shop I dug out a used grubby set of MSD spiral core wires that I last used 10+ years ago on the dirt car. That 454 dramatically smoothed out with just a change of wires.

Again, quality of the wire, not necessarily the concept of graphite core. As others have mentioned, the O.E.'s churned out millions of new cars last century with graphite core wires. Of course they were gone when each cylinder got it's own coil. Interestingly, the factory type wires for my 99 suburban are spiral core rather than graphite. Perhaps even the O.E.'s were phasing out the use of graphite wires at some point.

Agree its sort of like in theory a plastic hood/grill and a fiber fuel tank underneath works fine on a farm tractor,until the tractor is taken out to be used on a rough brush
hogging job where theory clashes with reality.

Well stated. Thanks for the concise history lesson. Jim

Unless you listen or transmit using the AM radio band on your tractor radio. Using non rester plugs and non resistor wires will eliminate future intermittent phantom problems . If using electronic ignition, use spiral wound induction suppression wiring. I agree that the spit and sputter is like an airfoil mixture problem due to crab, manifold and gasket problems . When was the last time the valves were set ?