Don't be so quick to throw the Bums out ...

....not the DemoRats and the RINO Republicans but used spark plugs! (he-he-)

It is normal for the electrode center tip to wear round and erode as tiny particles of metal are removed by use (high voltage sparks and corrosive gases formed by combustion) and as the electrode wears the gap increases. The amount of wear to sufficiently widen the gap takes many miles but eventually it will wear beyond the gap specs and the coil has to work harder to jump the gap. This requires more voltage and under hard acceleration the system may be able to supply it and it may not. Performance can decrease or become severely affected.

The remedy is to re-gap (and clean as necessary) or replace the plug. However, re-gapping can be done repeatedly until the center wears down fairly close to the insulator and then that's it, the plug's life is over.

When cleaning and re-gapping, the tip of the center electrode (where is has worn round) should be carefully filed just enough to make it flat like it was when new. This can be done with a small file like a point file used to file ignition points. The reason for this step is that less voltage is required to jump the spark between sharp corners than between rounded edges.

The gap is adjusted by carefully bending the ground strap (or ground electrode as some call it) and measuring with a feeler gauge. Be careful not to put any pressure on the center electrode or insulator area. The insulator can crack off and you can also loosen the plug up where it fits against the center electrode. Use a feeler gauge with round wires if you can obtain one. It's easier to be more accurate with a round wire feeler gauge than a flat feeler gauge when measuring plug gaps.


Larry B.
 
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Sounds good but on a side electrode plug I use a wire gauge and try not to file the electrode. I like the feel of the wire better. But that's just me......
 
Larry's right. The sharp edge gives the spark a better place to go than a rounded surface. I think some performance plugs even have center electrodes that are somewhat pointed. While working at a major oil co research center, we studied spark kernel growth using laser-assisted photography. The study was aimed at inventing a fuel additive to prevent misfire, as even one hiccup in a modern engine (or any engine for that matter) increases HC and CO emissions. We found the spark "dances" around the electrodes in a random fashion; it's probably that phenomenon that causes the erosion of the electrode and leads to its rounded shape. $0.02.
 
Helpful tip. I continue to clean my plug regularly, but never considered filing the electrode flat again, I will do that next time. It wasn't something I was ever taught in auto shop.

I use carb cleaner and a brush to clean plugs. Is there another solvent that works better?

By the way, it's "Republican'ts"
 
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