Author Topic: SPARKPLUG EXTENSION AT PLUGWIRE END  (Read 3053 times)

Offline Brian Rupnow

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SPARKPLUG EXTENSION AT PLUGWIRE END
« on: September 12, 2021, 11:56:37 PM »
Has anyone ever seen or know of a sparkplug extension that looks like the one in this picture? The plug is a Rimfire .25-32.  I want to nest this plug down between two rocker arms and not have the spark shorting out and snapping to the rocker arms instead of to the end of the sparkplug. The red and yellow parts I show is the extension. The purple is the original rimfire sparkplug. The red part would have to be steel or brass. The yellow part would be something non-conductive that was resilient like rubber so it would "grip" the end of the sparkplug. Strange question, I know, but I have a reason to ask.---Brian

Offline Brian Rupnow

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Re: SPARKPLUG EXTENSION AT PLUGWIRE END
« Reply #1 on: September 13, 2021, 01:17:54 AM »
Back a year or two ago, when I was trying to set up a governor on that twin, I designed and built a set of heads that moved the sparkplugs up to the center of the heads. The heads were great, but the sparkplugs were so short that sparks were jumping over to the rocker arm towers.


Offline Roger B

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Re: SPARKPLUG EXTENSION AT PLUGWIRE END
« Reply #2 on: September 13, 2021, 07:46:06 AM »
I think that the red part in brass or steel would be too heavy.

If you can fnd a silicon rubber tube that will fit snugly on the plug body then build up the ignition wire to a suitable diameter (with heatshrink?) to be held in the same tube and solder a small spring onto the end of the ignition wire to make the contact too the sparkplug.
Best regards

Roger

Offline Zephyrin

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Re: SPARKPLUG EXTENSION AT PLUGWIRE END
« Reply #3 on: September 13, 2021, 09:03:46 AM »

Recessed sparkplug on a small cylinder head leads to arcing on many spots and also requires a special thinner socket spanner...
you may isolate the plug as indicated by RogerB, which should do it, or have a go in making your own special longer plug.

Offline Brian Rupnow

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Re: SPARKPLUG EXTENSION AT PLUGWIRE END
« Reply #4 on: September 13, 2021, 08:22:48 PM »
I find that Corian is rather brittle stuff to work with. Is there any other material that is commonly available but is still machinable and a good insulator? I have made my own sparkplugs in the past with Corian, but wasn't terribly impressed with it.

Online Jasonb

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Re: SPARKPLUG EXTENSION AT PLUGWIRE END
« Reply #5 on: September 13, 2021, 08:27:33 PM »
I've used glass tube, just cut it to the length you want with a diamond Dremel disc



Offline Brian Rupnow

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Re: SPARKPLUG EXTENSION AT PLUGWIRE END
« Reply #6 on: September 14, 2021, 02:52:10 PM »
Okay---Don`t laugh.--I have a solution. The inner portion will be made from brass. The outer section will be kiln dried oak wood. The brass core will be Loctited into the wooden outer shell. The wooden outer shell will be Loctited to the sparkplug. The sparkplug never gets hot enough to burn the wood. The wood is a good insulator, and the brass passes the current down to the sparkplug. best part of all is that I have the material to do this.

Online crueby

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Re: SPARKPLUG EXTENSION AT PLUGWIRE END
« Reply #7 on: September 14, 2021, 05:22:31 PM »
Loctite the brass to wood? Never knew it was compatible with wood.

Online bent

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Re: SPARKPLUG EXTENSION AT PLUGWIRE END
« Reply #8 on: September 14, 2021, 08:19:31 PM »
Hm, we found that loctite green (the wicking grade) and blue (removable grade) are conductive enough to cause stray shorts on printed circuit boards here at work.  Maybe it will carbonize enough to not matter once it's run awhile at high voltage?

Online Jasonb

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Re: SPARKPLUG EXTENSION AT PLUGWIRE END
« Reply #9 on: September 14, 2021, 08:38:11 PM »
That Glass and metal one I showed above was bonded together with Loctite "Black Max" #380 which has rubber in it.

Offline Brian Rupnow

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Re: SPARKPLUG EXTENSION AT PLUGWIRE END
« Reply #10 on: September 15, 2021, 01:17:50 AM »
Yes, you're right. no Loctite. I'll epoxy it together.

Online bent

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Re: SPARKPLUG EXTENSION AT PLUGWIRE END
« Reply #11 on: September 15, 2021, 04:08:48 PM »
Sounds right, Brian.  Jason, I'm not familiar enough with Black Max, but assume it's been formulated to be non-conductive?   I've been trying to source a decent retaining compound for assembly of circuit boards, but not successful yet.

Offline Brian Rupnow

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Re: SPARKPLUG EXTENSION AT PLUGWIRE END
« Reply #12 on: October 02, 2021, 09:16:37 PM »
Okay, the game plan has changed a little bit. instead of having part of the brass turned to 1/16" diameter, it's a lot easier to drill a 1/16" hole completely thru the brass and silver solder a piece of 1/16" diameter cold rolled steel in there instead.

Offline Brian Rupnow

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Re: SPARKPLUG EXTENSION AT PLUGWIRE END
« Reply #13 on: October 02, 2021, 10:33:02 PM »
So, here we have two sparkplugs extended 1". I'm not sure how this will work, but I will leave them to "set up" for 24 hours so the epoxy is totally cured, and then we'll see.

Offline Brian Rupnow

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Re: SPARKPLUG EXTENSION AT PLUGWIRE END
« Reply #14 on: October 04, 2021, 08:16:55 PM »
For what it's worth---In this case wood is not a good enough insulator. I get zapped when just holding the wooden barrel. I had to try it and see for myself, but I would not recommend wood as an insulator.

Online crueby

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Re: SPARKPLUG EXTENSION AT PLUGWIRE END
« Reply #15 on: October 04, 2021, 08:43:26 PM »
Looked up spark plugs online, and found this quote:
Quote
5. Wood you believe it? – The ceramic material used in the spark plug insulator – the white body that wraps around the central terminal – is composed mostly of an aluminum oxide material designed to withstand the heat and pressure generated by the voltage that passes through the plug. That wasn’t always the case, however. Early spark plug designs used porcelain, mica (a silicate mineral), glass and even – we are not making this up – wood.
So, you are not the first to try it!

Offline Admiral_dk

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Re: SPARKPLUG EXTENSION AT PLUGWIRE END
« Reply #16 on: October 04, 2021, 10:06:34 PM »
It might work if dried to zero moisture - but keeping it that dry ....

Offline stevehuckss396

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Re: SPARKPLUG EXTENSION AT PLUGWIRE END
« Reply #17 on: March 05, 2022, 08:58:52 PM »
Hey Brian!

Just so you know for the future I now have the 1/4-32 sidefire plugs in standard length, plus .125, plus .250, and plus .375 lengths. I am also working on a line of plugs in those lengths where the cap is smaller and will have a silicon molded boot available. Trying to boot a 1/4-32 is kind of tough. I'm hoping to fix that.

Do not be like the cat who wanted a fish but was afraid to get his paws wet.

Offline Brian Rupnow

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Re: SPARKPLUG EXTENSION AT PLUGWIRE END
« Reply #18 on: March 05, 2022, 10:47:47 PM »
Thanks for letting me know, Steve. You make good product.---Brian

Offline GordonL

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Re: SPARKPLUG EXTENSION AT PLUGWIRE END
« Reply #19 on: March 06, 2022, 12:50:56 PM »
Hey Brian!

Just so you know for the future I now have the 1/4-32 sidefire plugs in standard length, plus .125, plus .250, and plus .375 lengths. I am also working on a line of plugs in those lengths where the cap is smaller and will have a silicon molded boot available. Trying to boot a 1/4-32 is kind of tough. I'm hoping to fix that.

I have had reasonable luck with a 3D printed boot.

 

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