Modern Champion Spark Plugs - bad experience?

[scott12180]

I put a brand new set of Champion W-18 spark plugs into my 1926 Packard.

The engine started hard, idled somewhat roughly, but when I got onto the street, there was a severe intermittant miss on several cylinders. After 1/2 mile I got back home and found that at least four of the eight were firing irregularly (fouled, and after only 1/2 mile!) I replaced all the new Champions with my old set of Blue Crown Huskies (same heat range) and the car ran just fine -- smooth and powerful. Why??

I had this problem years ago on a Franklin, except I did not think it was due to spark plugs. After years of fiddling, I finally gave up in frustration. A spark plug is a simple enough device, isn't it? Now I believe that there's something about modern spark plugs that may not allow them to work on old ignition systems. (The Franklin had a magneto) Is there? Do modern plugs require voltages or currents far in excess of what antique ignition systems can produce?

Anyone else have a bad experience with moden spark plugs? Just Champions? Or what?

--Scott

[Dave@Moon]

When you say "fouled", were they covered in carbon build up or just coated with a resin from dried fuel? It may be that your new plugs had been mishandled at one time in the past and had hairline cracks in the insulator that allowed the plug to short rather than fire.

[Guest carlnut50]

Hello,I am not familiar with the Champion plug you mention but I do know that resister plugs require more voltage and do not work very well on a magneto system unless it is very hot.The resister part is simply a gap in the insulator that the electricity has to jump to reach the electrode at the spark gap.On a battery/coil system,It causes the coil to draw more current and therefore produce a higher voltage to jump the gap to ground.You can check your plugs with an ohmmeter for continuity and determine if they are resister ones or not.

[Guest De Soto Frank]

Scott,

I have been favoring Autolite plugs in my drivers for the last several years.

I had a great deal of trouble with Champion plugs shorting in my 1970 Honda CB-450 motorcycle ( in less than 200 miles, no obvious signs of carbon or oil fouling...)

For your Packard, see if you can get a set of Autolite 3076 plugs: these are a 7/8" thread plug, I use them in my old Gravely Model"L" tractors (some of which used Champion W-18).

I got my last 3076's about five years back - they were new production, in new boxes. And were about $1.50 from my local A & A Auto Stores here in Wilkes-Barre.

Good luck !

[Terry Bond]

Spark plug history lesson #4-the earlier plugs worked better because they had a different insulator design-the center electrode was up in a recessed area inside the insulator. If the plug became fouled or sooted, the short circuited spark had further to travel to ground, so it took far more oil and soot to short them out. Remember the spark will jump only across the shortest distance. Realizing that, many early spark plug designes were based on what was known as the "Canfield Patent (1898). Modern spark plugs probably dont have that feature. Center electrode is usually enclosed at the tip of the insulator giving spark shroter distance to travel. Our earlier cars probably run pretty rich to start with that that'll soot them up quickly, shorting them out faster than the earlier type with the center electrode up inside a deep recess area.

Terry