Is it possible for an ignition spark to be TOO hot?

Dear Car Talk

Dear Car Talk | Jul 01, 2001

Dear Tom and Ray:

Can one have too hot an ignition spark? There are several aftermarket ignition systems available for older car engines, most claiming to produce more voltage than stock systems. But can you overdo it? Will too hot a spark wear out the spark plugs faster or cause any other problems? -- Clyde

RAY: It will wear out your spark plugs faster, Clyde. It'll also wear out the other parts of the secondary ignition system faster -- the plug wires, rotor, distributor, etc. So you'll be buying new ignition parts more often, but it won't do any permanent damage to your engine.

TOM: The idea is that a higher-voltage (or "hotter") spark will do a better job of burning all of the fuel in the cylinders. And technically, that's true. But in reality, it only really helps if you suffer from excessive turbulence in your combustion chambers.

RAY: My brother suffers from that, and we've been trying antacids ... with no luck so far.

TOM: Turbulence inside the cylinders increases as the engine speed increases. And if your spark is not hot enough, the swirling gasoline-and-air mixture can blow out a weak spark, causing an occasional "miss" or "stutter" at high speeds.

RAY: But if you're not experiencing that problem, you probably won't notice the difference a hotter spark makes.

TOM: Of course, you're welcome to install a hotter ignition system anyway, Clyde. You won't do any harm. But let us know in advance so we can invest in some auto-parts stocks.

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