Well, my spark plug backed out, and slightly stripped the hole somehow. Here's a picture of the old plug so you can see how badly the threads were damaged: http://www.geocities.com/n0disguise/plug

The threads aren't damaged too bad, it seems. Anyone have any tips on how I might un-strip the hole and get the new plug in? The new plug won't catch at all.

 

Harry - I really respect your input to this forum, but wouldn't a tap be used to chase the spark plug threads in the head?

nodisguise - If you're certain that threads were damaged, I would want to put some kind of reinforcing insert into the dmaaged area. As hecash suggests, a helicoil would work fine and is a standard solution to this problem. Just make sure it's installed correctly, locked in place properly, and all the metal bits are vacuumed out of the work area.

 

Guys.. it doesn't look like he stripped the threads, but if he did then he is hosed. You need to be super careful with the spark plug threads because those are very precious threads!!! If you need to replace those threads you are up the creek. You'll need to pull the head off at the very least, and I doubt that you'll ever have your head right again. Honestly if I ever did that, I would replace the entire head....... But that's just me.

Why is that spark plug all black like that, because it was loose? I imagine the coil would be hosed as well.

Good luck!

Chris

 

Also, if you tap the head again, you better make sure that the tap is perfectly in line with the existing thread. In addition, I wouldn't re-tap it with the head on because all of the shavings are going to go down in to the cylinder and will likely get lodged in to the cylinder all and screw up your compression.

I believe the thread is 18mm ..... and I think it's the same thread type as an o2 sensor, so you can test it on an o2 sensor bung before you hose your head casting..

Chris

 

Yeah, I should have said "bent the threads" instead of "stripped them." Only the first one or two threads on the spark plug are bent, so my guess is that only the top one or two of the threads in the head are bent. Thinking about it now, I'm not sure it's such a bad idea to just use a tap.

I'm thinking of worse comes to worst, I could just have the top 1 or 2 threads just grinded out completely. There would still be plenty of threads left to hold the plug in place. Is this a terrible idea?

I just got another idea. The threads really don't look that bad. I'm going to try to screw the old spark plug back into it since the threads have been smushed a bit, they'll probably fit, and hopefully the fully intact threads near the base of the plug will straighten it out enough to catch the threads on the new plug.

 

Ok, that didn't work.

I guess I'm just going to talk with my brother's friend who runs a machine shop and has taps and see if he can come up with a way to tap it and keep anything from getting into the cylinder, or a way to get anything out once he's done. If anything, I can rig up an attachment for my carpet vacuum with a flexy straw, and some duct tape. I really don't want to go to have to take the head off.

Yeah, the plug came out and was hammering up and down between the coil and threads apparently. The coil was toasted as well.

 

Those plugs look so bad, I wouldn't insult my garbage can with them. Get a new set.

 

It was just one plug (and I already purchased a new one), and it only looks like that because it came out and was probably engulfed in flames. The others are fine.

 

This is an "aside":
Did you not get the spark plug recall done? I'm curious why the plug backed out in the first place.

 

Nope, I didn't. I bought it with 30k miles, assumed it was done, didn't find out it wasn't until a month or two ago when I went in for the taillight recall, but didn't have enough time that day to leave it there, and figured I'd just have it done when I went in for the seatbelt one (which takes a long time). I never got around to it. You have my permission to call me an idiot.