Collecting Antique Spark Plugs

Enlarge Image Image Gallery A tray of plugs from Bob’s collection.

Sumptuous beauty. Red Heads, Royals and Rajahs. “Rags to riches” drama. It may sound like a sizzling new mini-series – but the story here is collectible spark plugs. 

Hardly anybody, it seems, sets out to collect antique spark plugs. “Most of our people started with gas engines, tractors or antique automobiles,” says Lanning Baron, president of Spark Plug Collectors of America (SPCOA). “But the technology, the clever manufacturing, the ideas going through the inventors’ heads, it just draws you in. Really, it’s the same thing a gas engine collector would say about his hobby.”

Despite the nearly limitless supply of plugs, few collectors limit their hobby. “Spark plug rarity is often driven by unusual features of ‘gadget plugs,’” Lanning says. “It’s mind-boggling to see the variety. There are some people who collect, say, just plugs from their home state. But a real spark plug collector will go for anything. If it’s cool, you’re going to want it.”

Antique plugs have a certain practical appeal as well. “A lot of people who’ve gotten into spark plugs really appreciate the fact that they’re a lot easier to display than gas engines or tractors,” Lanning says. “My collection of 2,000 spark plugs fits in a comparatively small place. Who has 2,000 tractors?”

Engine heyday spurred boom
Fifty-seven Heinz products? Thirty-one flavors of ice cream? Compared to antique spark plugs, that’s kid stuff. SPCOA maintains a master list of more than 6,700 spark plug manufacturers operating from about 1900 to the mid-1930s.

“With the various models and styles, we figure there are at least 50,000 types of spark plugs out there,” Lanning says. “More than 2,000 U.S. patents were issued on spark plugs alone. So many people wanted to get on the bandwagon, and everybody had a ‘better mousetrap.’ There were a lot of gimmicks and gadgets.”

First invented in the 1890s as a component of the fledgling internal combustion engine, spark plugs took time to come up to cruising speed. Early engines burned a lot of oil, fouling plugs in the process. “There was a lot of focus on developing new spark plugs that wouldn’t foul,” Lanning says.

In addition to conventional collectible spark plugs, “gadget” plugs fall into six categories:

• Quick detachables that could be easily removed without tools for quick cleaning;
• Double-end plugs that could be flipped when one end fouled;
• Breathing plugs designed to allow clean, cool air to be drawn in over the hot end of the porcelain, burning off deposits;
• Primer plugs that allowed small additions of fuel into the cylinder for easy starting;
• Coil plugs that combined coil and plug into a one-piece unit;
• Intensifier plugs with a second firing gap, said to make the plug “fire hotter and longer.”