Spark Plug Wires -- Which Ones ???

[bcomo]

I got this flyer along with a spring that I ordered from Daytona Parts Co. (Carburetor).

I wanted to post this -- but PLEASE don't shoot the messenger. I don't know exactly what to make of it, and offer it for discussion.

"Daytona Parts offers new high quality "Metallic Core" spark plug wire sets for all pre-1970 vehicles.

These wires were made to operate and deliver correct voltages to the spark plugs thru low-resistance metallic solid core wires.

If you operate your pre-1970 vehicle with newer HEI supression RFI wires (Bart note: the ones that look like carbon core), you are causing low voltage to the spark plugs, which may result in hard starting, poor gas mileage, decreased performance, rich running, fouled plugs, and other symptoms that seem carburetor related.

All american ignition systems from 1974 and up, use HEI (High Energy Ignition) with output of 35,000 to 45,000 Volts. Your original point sytem runs in the 20,000 Volt range, and will not be able to provide the necessary voltage through modern HEI wires."

[tbird430]

U many be on 2 something there "bcomo"....

[bcomo]

I just spent $40 on a new set of HEI type wires. I didn't know that the old kind were still availabe, and to tell the truth, I never thought about it.

Jon: Where abouts in Texas are you? I'm in San Antonio -- are you HOT enough there??

[JohnG]

hi Bart

Without alot of research I think you are headed in the right direction.

Let's think about the basics of spark plug wires for a sec. On the one hand you want as much of the spark that your (somewhat feable) coil is putting out as possible to ignite all the gas you can. Note your spark plug gap is supposed to be .032 to .035 which indicates there isn't all that much spark to work with. On the other hand people didn't want the sparks scrambling their radios (which also weren't all that great) so something less than solid metal (very low resistance = little loss of spark) wires were used (put an Ohmeter on your new ones - readings are in the tens of thousands of ohms). As you have correctly noted, newer cars have higher output coils (note how much wider modern gaps are) and thus the wires can be made to be merciful to the radios (meaning higher resistance). I am told that the higher resistance wires also cut down on electronic noise that can screw up the onboard computers, but I cannot vouch for this myself.

But your coil does not have the higher, modern output (unless you have swapped it out) so as noted, if you use modern wires, you squander what modest spark you began with.

In short (no pun), this is very likely sound advice and an appropriate product. In fact I am gonna see what I have for resistance on mine and perhaps upgrade.

If you do buy some, would you put a multimeter on one and see what you have for resistance??? I would be most curious.

I will give you an example of old and modern not mixing well. When I bought my TBird in 2003, the previous owner had installed new points, plugs, cap and wires. The car would often barely not start or not start at all when hot. I checked all kinds of things and came up empty. Finally it turned out that the plugs were at a "modern" gap of about .043" . I closed the gap down to .032" and the car started and ran fine thereafter. I now have it back to .045 but only after installing an MSD high output coil.

Bottom line: anything conducive to the best possible spark is good, in my book.

John

[bcomo]

JohnG:

So, your current (no pun) wires, are HEI wires same as mine? I'm using the Pertronix Coil with 12 volts to it. That should up the Volts to those wires, same as your MDS coil should.

If you take an Ohm reading on yours, measure the length of the wire that you used and let me know what the Ohms were. I'll do the same on a similar length and let you know.

But I'm wondering -- isn't the final judgement the way the plug looks? I mean, if the plugs are cream colored, then isn't the combustion correct? Or, is that just correct mixture?

I'd hate to change wires just for the sake of doing it.

[JohnG]

hi Bart

I don't know what mine are...I have never changed them. I did go through them with the multimeter a year ago to see if any had problems. I have notes on what resistance values I got which I will look up. I will put up another post when I dig those out.

Basically you are correct... if the plug is firing properly (as evidenced by how it looks and how the car runs) then things must be set up correctly.

If you are (as I am) looking for a little improvement and better gas mileage, then a better coil and better spark are a goal. If the wires are an impediment to that, then I would look for alternatives. I had not thought about the wires in awhile so I am glad you got me thinking about them.

Since this is a "system" (ignition), whenever you change one component or setting, a strong possibility exists something else either will suffer or need to be changed. A high output coil is tougher on the points. Higher resistance wires impact the spark... etc etc.

Semi related story: about 40 years ago we had antennae TV (got 4 stations on a good night). Each night about 8:00 one of the neighbors would drive by in his pick up truck and the TV would respond as he had solid copper core wires. ("there goes Paul".... sure enough I would look out the window and see his truck) My father noted at one point the pattern had become ragged. He called the guy up and suggested he consider a tuneup. Sure enough, two plugs were not firing. Next night, when he went by, the perfectly regular pattern on the TV reappeared at 8:00.

John

[Alexander]

I like that story of the truck with the copper core wires.

[JohnG]

....cheap way to get your vehicle tuned up "on a scope" !!

I looked in my notebook and found my wires last fall had readings in the ball park of 8.5 using the 20K scale on the ohmeter, so I am taking that as meaning 8500 ohms.

I just changed the wires in my Subaru so I will get one of the discarded ones and see what it has for a value.

Later on.... I found a discarded one from my wifes Saturn. I got a reading of 5.5 on the 20K scale. I then took the wire to the #1 cylinder of the TBird and got 11.4 on the same scale. Now the TBird wire is about twice as long as the Saturn wire, and resistance is proportional to length, so it would seem these wires are made out of the same material and have the same resistance (per inch). The TBird wire has some printing on it about silicone core.

This being the case, by what Bart quotes, I have the wrong wires. So Bart, if you don't want those wires, send 'em along!
John

PS: Do these Daytona guys have a "Contact Us" kind of email address or website ?

For you TX guys, I am in MA and the outside temp is 55. No fooling. Got a heavy shirt on.

[bcomo]

I also got kick out of the antenna story. Who would think that's possible.

The wires that I have on the car now now are new Autolite HEI type wires (the carbon core ones) that are higher resistance. My AP45 plugs are pure cream colored, so that's why I'm wondering if I should even buy the metallic core wire that Daytona is talking about.

Talk to Ron at Daytona Parts Co. in FL (386-427-7108). This guy is very easy to talk to, and is extremely knowledgable about carbs, and ignition. He will actually tell you much more than you wanted to know.

Their web site is http://www.daytonaparts.com/

Note: They do not list the plug wires on their web site. You have to speak to Ron about them, as they were just in the flyer that I got. Price is $40 + shipping. They are universal sets, so the plug boots are attached, but you have to cut the wire to length and install the distributor boots. They are all black, just like stock.

Tomorrow, I'll take an Ohm reading of one of the wires on my car and let you know what I got. I'm interested too.

P.S. Enjoy your cool weather !!!

[Guest]

I do believe modern wires reduce by a small amount the energy going to spark plug but I think it is related to plug gap size.How much smaller I dont know and how would you test all the wires on a running engine without some special equipment. How much energy is needed to jump the spark plug gap, anymore is wasted. Run new modern wires-close the gap on the plugs, just as you would increase it with the Pertronix. Just installed new Motorcraft replacement wires on my 60 430 and it runs better than the old wires.

[bcomo]

Andy:

Those are the same wires that I just put on my 430 and I also changed to AutoLite AP45's. The plugs are running a cool cream color, and it runs great.

I don't know if anything could improve on that.

[Guest]

I agree, same plugs. Did a interstate run of about 30 miles and checked everything-plugs running clean and power was there at my right foot when needed. I think we will be ok with these wires, I'm still running points in mine!, still scared of Pertronix after the failure in my 56, maybe when my stockpile of points is gone I will go with the Pertronix, I think I will change to the powergen also, to keep the volts up as needed by the Pertronix .

[6TB1RD]

Lost

JohnG.
What All did you have to do to your ignition system to run the MSG high out put coil? I have been thanking of installing one but do not know the effects on the ignition system.

Bart.

I thought all the coils were 12v!

If I understand correctly are you saying you removed the resister wire? or is there something else, I know the wire from the starter switch is straight 12v, but I also thought the wire resister wire was also 12v!

What all needs to be done for a high output coil?

[JohnG]

To use an MSD high output coil for points based ignition systems (they have a number of products), I also (this is important) got a matching ballast resistor so that the coil would have the proper current to (through) it. I think I posted the part numbers on a post about gas mileage back in July. (later: the MSD coil is 8002 and the ballast 8124)

I have a 1958 so I have a ballast resistor, while a 1960 (I think) has a resistor wire. Both do the same thing, namely they limit the current through the coil and points (or the points fry, among other possibilities).

So if I had a 1960, I would remove the resistor wire, add the MSD ballast resistor in its place, and hook up their coil.

All coils are 12V as their primary voltage but have thousands of volts for the secondary voltage that fires the plugs. This is where they differ.

I dont think the cost of the MSD components is more than $50 total, by the way. They have a pretty good website.

If anyone goes this route, as always, buy a backup ballast resistor because if it fails, you walk. Can be replaced in 1 minute or so.

john

[bcomo]

George:

Your right, the coils are 12V. But, the 60 uses a 12V resistor wire (a short pink wire under the dash in series with the coil wire) that will effectively reduce the Voltage going to the coil.

The FlameThrower instructions say to use a voltmeter from ground to the incoming hot lead (+) on the factory coil, car running, and if you get less than battery voltage (I think that I got 6V) you should remove the resistor. You don't have to do that, but you will just get less output from the FlameThrower -- but still more than the stock coil. So, it's really personal preference.

I unwrapped the harness from the firewall to the coil, and ran a 12V wire directly from the "key on" hot side of the ignition switch to the coil. So, I am not using the original wire that comes from the resistor.

This just eliminated the resistor wire without having to get under the dash and cut wires. And you can't tell that anything was done.

JohnG:

I measured the Ohms on one of the AutoLight HEI type wires (carbon core). The #6 cylinder wire reads 8,000 Ohms. I don't know if that's meaniful, but there it is.