How do I remove a broken spark plug?

[Farrar]

Can't believe there isn't a thread here already, so I'm starting one.

Technically, I don't have a broken spark plug stuck in the engine. What I have is the end of a compression tester stuck in the engine. Technically, though, it's the same problem.

The internet is full of advice on how to remove broken spark plugs from truck engines, but nothing for the PRV. I can't find anything long and skinny enough to get down in there and grip what's left of the thing.

Suggestions?

[opethmike]

Can you post a picture of it? It could be broken off in a bunch of different ways.

[David T]

This is potentially harder than the removal of a typical broken spark plug. With a spark plug you have some idea of what you are dealing with. There is no good way to grab anything in that well. Not too many ways to deal with this. The best bet might be to take the head off and have a machine shop deal with it. With the head off maybe you can get an "Easy Out" or something and try turning it from the other end? Worst case you punch it out, destroy the threads and fix with an threaded insert.

[Ron]

+1 on a pic!

Seems you might use an Easy Out as is, i.e. w/o removing the head...

[Farrar]

OK, here's a pic.

58401

The hole is where the air goes through to register on the gauge. It's dead center, so that might be as good a place as any to put a drill bit. I went to the hardware store and asked for a long drill bit, but they suggested I buy a drill bit extension instead... which they didn't have in stock... so I ordered one online. In the meantime I bought a screw extractor set, but none of the bits is long enough to reach down in there. I guess I will have to wait for the extension to arrive.

Thanks, y'all.

[Ron]

fwiw, most Easy Outs have a square head on them, which would fit a 12 point socket....

I wouldn't drill it unless I had to because of the metal shavings that might fall into the cylinder (depending on how the tester end was made...).

[Farrar]

depending on how the tester end was made...).

If memory serves, at the bottom is a check valve. Assuming I don't drill into the valve,

... but what am I saying? I'll definitely screw this up. After all, I couldn't manage a simple compression test without turning it into a disaster.

Thanks for the tip.

[opethmike]

Pic says invalid attachment?

[dn010]

More details - how far in were you able to thread this before it broke, did it break while removing or while installing, etc. Also your picture did not come through.

[Ron]

Pic says invalid attachment?


Also your picture did not come through.

That's odd, it comes up for me...

How about this one?

58402

[dn010]

Thanks! That worked.

PITA but what I would try is -

Remove the collar/ring that goes into the plug well for more access.

Find someone to weld a rod to the extractor.

After rotating the engine to be sure the fitting doesn't hit, run the engine (you'll flood the cylinder) or find a way to heat the cylinder head up.

Try a long small pair of needle nose pliers

Try the extractor.

Try drilling with left-hand drill bit.

Try liquid metal on a rod pressed down into/on the fitting.

I doubt there is enough room to weld a rod to the actual fitting but that would be another option.




That's odd, it comes up for me...

How about this one?

58402

[David T]

If that part of the tester is hardened you will not be able to drill it or get an extractor to "bite" into it. Welding a wrenchable stub to it may be an option. Try tapping it back and forth, up and down. If you can get it to move you may be able to get it loose enough to turn. At this point it doesn't matter if you damage the threads, you can repair them after you get that thing out. I don't agree with trying to run the motor.

[dn010]

So don’t run the motor then. But find a way to heat the head up. Heat makes things much easier to remove.

[David T]

No good way to get the heat where you need it unless you remove the head. I agree heat can help but only if you can heat the right part. That part is only supposed to be hand tight. I can't believe it is so stuck that some tapping and prodding can't get it loose.

[DMC-Ron]

58402

Based on the photo, I would first start with a small extractor connected to an extension. The small extractor needs to fit into the inner compression tube. They make extractors small enough. The problem is a small extractor may not have enough grip to turn the stuck compression tool if it is somewhat tight. On the other hand, it may have broken because of lateral forces not because it was over-tightened. If so, it may turn relatively easy. If the extractor doesn't work, a next approach might be to select a reasonably stout section of tubing that will fit snugly right over the compression tool. Fill the end of the tube with JB weld 8627 steelstick steel reinforced epoxy putty. Keep the putty recessed in the tube to avoid getting any putty in the opening. Insert the tube and press it on the compression tool. This must be done quickly because the JB weld will begin to harden and you want it to still be pliable when to "set" it to the tool. Let it set for at least a day before trying to turn the tube and extract the compression tool.

Ron

[Nicholas R]

Try drilling with left-hand drill bit.


I'd be hesitant about drilling unless it was a true last resort. I assume this thing is hollow, and any drill shavings that drop are going to end up in the cylinder. I suppose you could send a hose connected to a vacuum into the cylinder afterward, but I still don't know if I'd risk it.

I'd probably try one of the square easy outs that you hammer into a hole. Find one small enough to go into the hole that is already there, and use it to extract it. There can't be much torque on it if you hand screwed it into place so it's just a matter of getting a bite on it.

[David T]

The smaller the extractor (Easy Out) the less strength it has and is easy to break off. I have had a bunch of cases where I had to fix something that someone broke a tap, a drill, or an extractor off in and that makes fixing things another magnitude harder than the original problem. Going for that extractor, drill or tap might seem like the quick, easy fix but you must consider what you are going to do if it doesn't work out as optimistically as you hope.

[Farrar]

I bought a drill bit extender. That plus the easy-out worked like a charm.

58413

Thanks, everyone!

[eight8toy]

I say take off and nuke the entire plug from orbit. It's the only way to be sure...

I've had some frustrating times with this car but you've definitely got it worse this time. Hope you're able to use some of the good advice above to get it out, good luck!

Edit: oh sweet you got it free while I was typing a reply, good job!

[Farrar]

I assume this thing is hollow,

Sorry, didn't see this until now.

No, it's not hollow. It has a Schrader valve in the end. I drilled just enough to fit the smallest easy-out in my set, then blew out the shavings with compressed air and used the easy-out. Looked down in there and it's clean.

This is an Arctron (sp?) compression tester kit, by the way - if anyone was interested.

[David T]

Well you lucked out. Was it the correct adapter in the first place? Why did it break off and get stuck? Make sure it did not damage the threads in the head. Run a thread chaser or a tap to make sure.

[Farrar]

I fault the design of the tube that came with the compression tester - it was screwed together rather than being one solid piece. (Since the tube is now broken, I will use the hose instead.) It didn't take much to remove the thing, which means it wasn't badly stuck in the first place, and in my opinion the tool was poorly designed to have a weak point so close to the end.

The threads are fine - I gently put the spark plug in and took it back out by hand and it was as smooth as silk. Cleaned the threads and then reinstalled with fresh anti-seize. Moving on to the next project now.

[opethmike]

Please let me know what the compression numbers are once you've done the test.

[Farrar]

Please let me know what the compression numbers are once you've done the test.

Will do. Might be another week or so.

[Ron]

So don’t run the motor then. But find a way to heat the head up. Heat makes things much easier to remove.FWIW, spark plug manufacturers and shop manuals all have warnings to let aluminum heads cool before removing the plugs...

[dn010]

FWIW, spark plug manufacturers and shop manuals all have warnings to let aluminum heads cool before removing the plugs...

Understood, but the situation here is trying to remove a stuck object. Running the engine with the cylinder dead won’t make the steel object expand like a spark plug that is firing.

Regardless, congratulations on getting it out. Now, onto the next problem.