Lawn Mower Spark Plug Question

1
Any spark plug gurus around?? I bought a couple of RC14YC plugs for my Toro mower w/Briggs OHV engine. The existing and one of those received has a blueish metal ring just below the hex. One of the new in same packaging (496018S / 5092 B&S) doesn't have the ring at all, just a groove. Curious if anyone has a clue as to what this ring accomplishes and/or is it necessary? See following pic.
RC14YC Spark Plug Blue Ring.jpg
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Re: Lawn Mower Spark Plug Question

3
The gasket/seal ring is on the threaded side as shown in pic. The blue ring is just below the hex, again as shown in picture. It's almost like an O Ring, except metal. I expect it has jack to do with how the plug works - just curious why it's even there or if it serves any function other than causing an old fart to ask questions about it.
"Being Republican is more than a difference of opinion - it's a character flaw." "COVID can fix STUPID!"
The greatest, most aggrieved mistake EVER made in USA was electing DJT as POTUS.

Re: Lawn Mower Spark Plug Question

5
Good guess, BUT spark plug boot/cap doesn't go past hex and ring is below hex. My initial thought, it was a heat sink, but then same model from some others don't have the ring.
"Being Republican is more than a difference of opinion - it's a character flaw." "COVID can fix STUPID!"
The greatest, most aggrieved mistake EVER made in USA was electing DJT as POTUS.

Re: Lawn Mower Spark Plug Question

7
Meh, probably something on the manufacturing side that shouldn’t affect the consumer. The Eggheads have their reasons. I’m guessing they found a way to make it cheaper over time and still deliver the same (or similar) level of service life on the plug.

But I’d wager it’s original intent was to act as a vibration buffer, a softer metal to keep the ceramic from cracking.
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Re: Lawn Mower Spark Plug Question

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Wino wrote: Tue Apr 16, 2019 1:44 pm The gasket/seal ring is on the threaded side as shown in pic. The blue ring is just below the hex, again as shown in picture. It's almost like an O Ring, except metal. I expect it has jack to do with how the plug works - just curious why it's even there or if it serves any function other than causing an old fart to ask questions about it.
yep, I mean the seal in the joint between the two metal parts surrounding the ceramic
Image

Re: Lawn Mower Spark Plug Question

11
Since the ceramic reaches all the way to the gap, the blue ring obviously is part of the attachment mechanism between the metal of the hex, and the threaded part hold them together and the ceramic in place. It may be slightly softer metal.

But it doesn't matter. When you run your mower for a few hours, the ceramic near the gap should a light to moderate brown. If it's white you're running too hot because it's running too lean and risk damaging the valves, piston and cylinder. If it's black, you're running too rich and too cool and will eventually foul the plug first, then the engine. Lots of ways to fix both problems from simply changing the octane, to adjusting the mixture, the advance (if the mower still has one), or if you should run a cooler or hotter plug.
"Even if the bee could explain to the fly why pollen is better than shit, the fly could never understand."

Re: Lawn Mower Spark Plug Question

12
Bisbee wrote: Tue Apr 16, 2019 2:15 pm Meh, probably something on the manufacturing side that shouldn’t affect the consumer. The Eggheads have their reasons. I’m guessing they found a way to make it cheaper over time and still deliver the same (or similar) level of service life on the plug.

But I’d wager it’s original intent was to act as a vibration buffer, a softer metal to keep the ceramic from cracking.
I'd guess this.

Or it could just be "Bling".

Re: Lawn Mower Spark Plug Question

21
Spark plugs are designed for specific levels of heat dissipation. Too hot (the ceramic near the gapped electrodes is white) and you can burn your valves or pit your piston's head, or cause dieseling. Too cold and the tip will be black and the plug can foul with carbon build-up in the cylinder. Usually not as serious as too hot. Proper color is tan.
"Even if the bee could explain to the fly why pollen is better than shit, the fly could never understand."

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