Spark Plug Porcelain Electrode Repair

Steve Ciccalone

Well-known member
While cleaning a set of original '30 Champion 3X plugs, I found one of the porcelain electrodes cracked around the bottom where it sits in the base. Has anyone been successful in sealing a crack like this so the plug wouldn't arc. The repair will not be visible when the plug is assembled. Thank you.
 
Steve, I think it's hopeless because you're dealing with two factors: High temperature & compression. If you are like me and like to tinker,hey what the hell it's broke and you have nothing to lose. I would try opening the crack with a Dremel tool with a small cut off wheel,then try some high temperature Epoxy. I know I'm going to catch hell on this one. Remember you've got nothing to lose.
 
Bob, that's not an unreasonable suggestion. Two other guys mentioned the same approach. I found a replacement yesterday so I'm going to try this. I understand there is even a brush on type porcelain, similar to nail polish, that I'll try as a top coat.
 
I'm sure it would work but the question is how long? The last thing you would want is a break down on a sunny SundayA few hours away from home and nothing around besides cows and chickens:D. Lots of what your looking for around.
Bob, that's not an unreasonable suggestion. Two other guys mentioned the same approach. I found a replacement yesterday so I'm going to try this. I understand there is even a brush on type porcelain, similar to nail polish, that I'll try as a top coat.
 
Bob, that's not an unreasonable suggestion. Two other guys mentioned the same approach. I found a replacement yesterday so I'm going to try this. I understand there is even a brush on type porcelain, similar to nail polish, that I'll try as a top coat.


Steve,

Make sure, when you use the "brush on type pocelain", that you feather and mesh the "wet stuff" against the metal base. If you don't, when you go to tighten the base against the "fix" it might brake even more.

Pluck
 
I'm sure it would work but the question is how long? The last thing you would want is a break down on a sunny SundayA few hours away from home and nothing around besides cows and chickens:D. Lots of what your looking for around.

We are talking about a spark plug, if it fails the car still can run.
This is not a major Item like a timing gear,or crank shaft & etc.
 
Consider that if it does break, a piece of porcelain might fall into the cylinder and cause more problems. I know, something else to worry about. It is too bad to lose one of those plugs, but.........?
 
Steve ....I'm with Flathead on this problem......but if you must try, find a guy that fixes boilers, high pressure and heat, we used some kind of stuff(you had to mix it) in exhaust ports(racing engines) 40 years ago. Just a thought, Dudley
PS..it worked good
 
I think that the repair would create an insulating barrier to heat transfer, altering the heat range ---even if you can get a good enough seal to prevent escape of the spark.

It is an interesting experiment though, let us know how it works.

Make a sample of different glues to check if they end up conductive ---see if the coil wire can spark through the sample.
 
My guess is the two components are going to expand at different rates when they get hot. Unless the expansion is the same for the two components, its probably not going to work. If the porcelain expands faster, the epoxy will crack. If the epoxy expands more, then the plug might crack further.

If you try it, i wouldn't go to far and check it, or just let it warm up in the garage. You can always carry a wrench and the spare plug in the car just in case.
 
The whole purpose of asking this is because I need these for "show" at French Lick. Thankfully, I found another electrode but I'm going to still go forward with the repair to see if it can be done. Somebody mentioned boilers. I'm a retired Coast Guard Marine Inspector (oceangoing commercial vessels) and I learned a little about 1100psi propulsion boilers and 1000 degree superheat. I'll let you know how this turns out. At the price of original 3X plugs, we should find out if a repair can be done..
 
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