removing stripped spark plug - suggestions?

I am parting out a 1990 white miata, and spark plug #3 is badly stripped at the part where the spark plug attaches to the socket, not the thread
that the spark plug itself goes into. The spark plug is completely stripped, and the part of the plug that the spark plug wire boot attaches to is broken off. The remaining part of the plug is too far down in the narrow well to grab with any tools that I know of, and I am afraid that a tap and die would just send pieces down into the engine.
I have never seen this before. Has anyone else had this occur and did you find a solution? From what I can see, I am going to have to take off the head and use vise grips to get the plug out.
Thanks,
Pat
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It's not possible to grasp that plug with any vise grips I'm familiar with; head on or off. Stripping the hex on the spark plug isn't unheard of. The remedy is to grind a bevel or chamfer around the end of the spark plug socket so that it can reach lower in the spark plug well and grip what ever is left of the hex. If the hex is truly and completely gone, a 20mm 12 point deep socket driven over the remains of the plug might work.
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Last resort, you could sacrifice a socket... Apply some JB Weld and let it set over the plug until it dries. Never tried it, but it sounds reasonable as long as you're careful not to "weld" the socket to the camshaft cover. Guess I would try this as a last resort.
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There is a type of socket that has a bunch of needles inside. These will form around the damaged plug, and allow it to be removed. A big if is to get the correct size that will fit in the well and around the plug. Otherwise, the steel filled epoxy method sounds good. Since sockets are almost always slightly oily driving the mess out afterwards should be reasonable.

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Chuck wrote:

Thanks for the responses, I will look for this needle socket and see if it looks likely to do the job, otherwise I will go with the JB Weld method. My main concern is that JB Weld is very drippy and takes a long time to set up, so I would really need to protect the spark plug from becoming permanenty attached to the engine, as was mentioned before by Bryan. I will also try the 20mm socket first, but the hex on the spark plug looks like it is truly gone, someone has tried to remove this before I got to it.
There is a quick-set version of JB Weld, I'll probably try it first and see if it holds on enough to break the spark plug free. I am thinking about stuffing the area below the socket contact point with plastic wrap or some other non-absorbent material. Any other suggestions on keeping the bonding agent out of the spark plug threads/manifold area would be very welcome.
Sacrificing a socket is no big deal, as I think that this is a good, recently serviced engine that I can use in another miata or sell it if I can get that plug out.
Thanks again and I will let you know if it works.
Pat
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Wax? Oil? They always say the surface should be clean.
Leon

--
Leon van Dommelen :) Bozo, the White 96 Sebring Miata .)
snipped-for-privacy@dommelen.net http://www.dommelen.net/miata
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Leon, Tools don't rust if they have an oil film. Besides, not everyone has the spare time to do a hospital grade cleanup.
http://www.dommelen.net/miata

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Chuck wrote:

I think that what he is saying is to use oil (or wax) to keep the JB Weld from bonding to the engine and spark plug threads. The instructions on JB Weld say to apply to a clean, non-oily surface. That is probably what he was referring to, not the condition of the tools themselves.
Pat
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Leon van Dommelen wrote:

Wax, I never thought of that. It should be easy enough to drip some in around the edge of the plug contact point with a candle and let it dry before trying to bond the socket to the plug. I'll give it a shot this weekend.
Thanks,
Pat
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Leon van Dommelen wrote:

But - the goal here is not to bond to the surface, the goal is to create a form-to-fit socket around it. So wax/oil that prevents the epoxy from permanently bonding to the plug and/or socket (or even head casting) doesn't seem to be problem at all, as long as the epoxy cures and hardens.
Right?
Cheers - Dana
P.S. Good luck, Pat, hope you get it out...
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Dana H. Myers wrote:

Thanks, just tried it tonight, we'll see tomorrow after it dries.
Pat
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