Helicoils!!!! (Removal from deep holes)

[Stokestack]

Hi Stokestack,
You can make a wedge shaped tool from flat spring steel with a T handle like the bought ones.

Thanks! I've seen those, but of course the handles are way too short. I don't have a grinder, so making the metal wedge is already a problem, let alone mounting it in a handle.

I have a really long spade drill bit of the right width, which I could sand the little spikes off of with my belt sander (yep, I do have that). Not sure how I'd secure it in a handle; I guess I could make a wooden handle and put a couple of set screws in it. I'd rather not ruin it (it's handy for drilling through walls to run network cable and whatnot), but I suppose it's not too expensive to replace.

As for the fragment, I'm baffled as to when it appeared. The repair was done at least 10 years ago, but I didn't have misfiring until a few months ago; nothing was done to the engine immediately beforehand. The original diagnosis was bad plug wires, so I replaced both the wires and plugs. On reinstalling the wires, I noticed that the plug boot on the afflicted cylinder didn't sit flush against the valve cover the way the others did. Thus I suspected that the plug wasn't screwing in all the way, and the mess inside the well supports that theory. I think cylinder contents have been leaking around this plug; I checked the neighboring well and it's nice and clean.