I'm going to change the spark plugs in my 1978 camper special but I was going to use platinum plugs. I was curious about the differences between copper, platinum, and iridium plugs. I know copper plugs have the best performance but don't last. Platinum plugs don't perform as well but last longer and iridium plugs perform a little better and last the longest. But is it that big of a difference to from copper to iridium or platinum? Is it worth spending more money on plugs?

 

Copper plugs are an all copper construction. Platinum and iridium plugs have pads of the respective metal on the electrodes (Iridium is part of the Platinum family). Copper is the most conductive out of the bunch, and the cheapest to manufacture due to abundance. Platinum and Iridium are more rare, and are less conductive than copper. The tradeoff is longevity. Because copper is soft, it degrades quickly. Platinum is harder (4.5 vs the 3 of copper on the Mohs scale) and lasts longer.

Which is better? Depends on what you plan on doing with the vehicle. If it's gonna be a hard used towing rig, or hopped up motor, then I'd go with the higher end ones because you'll just burn through the coppers. If it's a stock motor in a truck that doesn't get used much, coppers will probably be fine.

I use NGK Vpower plugs in my rig. Not baseline, but not high end. It's a stock 300 in a DD truck. FWIW.

-Jameson

 

What I do... go to NAPA and buy Autolight standard plugs for your model/year/engine. They work well, are very cost effective and should last 30k+ miles unless you make other changes in the meantime. I'm not a fan of the "special" plugs in a classic as I see little value/benefit.

 

Stick with OEM. Not much point in shelling out the extra dough when the copper plugs work just fine for plenty long.