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Discussion Starter · #1 ·
My photo shows two Champion Plugs # RC12YC

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Notice the Tips are clearly different. How would Champion expect to get any satisfied customer with obvious differences in plug to plug with the same part number?

Just for information the smaller tip burned cleaner. The only one of the eight installed. I never noticed the difference till I removed them and was checking them over. All were black carbon deposit except the one with the smaller tip. Hard to see lesser black on the smaller tip plug. All were gaped .035”.

I compared to other old RC12YC plugs and they were like the group of seven with bigger tip.
I prefer the smaller tip plug as it ran cleaner in my engine. Any way to insure getting the smaller tip aside of opening all the boxes at the parts store? Suggestions?
 

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Discussion Starter · #3 ·
Delco, AC does not cover this size heat range. It was suggested to try auto lite non resistor ar3933. As I don’t prefer resistor plugs. I think the auto lite which is a mid temp racing series plug will work. I’ve had good results removing the resistor and replace with solid copper in champion resistor plugs to make non resistor. The tops unscrew and empty of resistor & spring. I have not found any other that will disassemble.

But honestly the small tip RC12YC (converted to non resistor) does have promise if I could find more of that type.
 

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Could be a running design change was made....the longer plug is old stock, the shorter one is current production maybe??
Could be the other way around too, with the shorter plug being the discontinued old stock and the longer the current production.
I don't know.
Could even be one style is counterfeit?

I'm with the "never use Champions club", I use AutoLite or NGK. ACDelco got iffy for a while, late 1990's, maybe they are back to good again?,
 

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Discussion Starter · #5 ·
The tip extension look the same the only difference is the diameter of the tip is smaller on the one. Counterfeit is highly unlikely as they were all in same boxed set of 8. But one never knows for sure. In the chance it is counterfeit, it performs better. Not expected of counterfeit. Possible manufacturer screw up. But your suggestion a design change is most likely. I hope the smaller diameter tip is the new configuration as that it is a cleaner firing plug. I’ll check out another new set of RC12YC’s to visually see what type tips they have. Auto lite “racing series“ non resistor plugs are an option. Auto lite non resistor AR3933 should fit the heat range. AR3934 & AR3935 being hotter.
 
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