Dry ice for busted spark plug?

Frankenstein

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#1
So long story short a 13 year old spark plug decided to snap while attempting removal (in a Nissan with freaking coils and a plug recessed almost 6 inches in the motor head assembly) earlier, number 5 extractor isn't exactly budging but after breaking (yes litteraly breaking) 2 socket wrench extensions I removed the extractor and toodled around with a large flathead and I think I saw it move a bit, which means it's probably loose but still stuck from probably carbon.

I'll go back to it tomorrow afternoon, wondering if anyone tried something like dry ice to shrink a part like this for better removal? Sometimes on stubborn stuck things I'll heat the whole area with a torch and then hit the specific part to be removed with a little bit of water carefully. Basically to make it smaller a bit and it seems to help, especially on old bearings to be yanked and the water means nothing nor burning off grease. Anyway there's an ice cream shop nearby that has dry ice for sale by the pound, would it be worth it to get a bag and trying to shrink it a bit?

The threads are steel, head is aluminum, aluminum shrinks and expands much more than steel so for it to be effective it has to be quick enough so that the aluminum doesn't shrink tighter around the threads than it already is.. Thinking about leaving it in the sun with the hood up to help get some warmth into the engine block before proceeding if I go this route. Any ideas before I try explosives? Plenty of gunpowder around here to make that happen.. Hmm
 


Frankenstein

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#2
Oh and I'm thinking dry ice simply because I've never broken 2 extentions before and obviously since it's dry it doesn't mean I'm putting water in an otherwise healthy engine.
 

Stoneman

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#3
Might not help, but can you use a bit of pvc pipe or something to concentrate the dry ice around the plug?
 

Spare_Parts

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#4
Soak it with pb blaster and let it sit. It will soften the carbon as well.

You could also try canned air for electronics. Flip the can over and spray the plug.
 

Frankenstein

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#5
It's been soaking up pb for over 12 hours now, the main problem is the plug that left the threads of the plug behind, it's hollow, looks like this right now.
GuzziBrokenSparkPlug002_640x480.jpg


The portion on the right is still in the motor, I'm thinking I could drop a pellet right in the middle of it, I could guide it or just move it with a long screwdriver. Either way this is what I'm dealing with, there's another stuck in the next cylinder over, and the ceramic started breaking off, but the plug is still in one basic piece at the moment.
 

Frankenstein

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#6
So it's still in there, no choice but to pull the head and make some very careful decisions.. At least the engine mechanical manual is only 192 pages with lots of detailed diagrams. Anyone know how to pull plug threads instead of using an extractor or drilling and helicoil? I'm thinking I could slowly use a diamond file to cut into it and stop at the top of the aluminum threads, then twist it inward to hopefully break it free, I'm kind of not happy with the situation and would like an easy solution. Fire, dry ice, and pb blaster have all failed and the only extention bits that won't break are the craftsman ones, I'm afraid to test that limit since it could wreck the head if the steel decides to take the aluminum with it...
 

G

greg78gs750

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#7
maybe try a left handed drill bit? bigger than the plug bit but smaller than the hole....with any luck it will spin it out?
 

gary55

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#8
This is probably a not so good idea, but if you have exhausted all other options maybe once the head is off if you could get a jig saw blade inside the threaded area to make a expansion cut . Then put some heat to it, and chase the threads in the head once you get it out. That would be my last ditch effort before the heli coils.
 

FurryOnTheInside

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#9
So the steel thread is stuck in the aluminium head? I never got around to trying this but I had a plan which was to try an alum bath to rot some nasty old pedals out of some not too shabby aluminium crank arms that they had become seized into.
 

Frankenstein

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#10
So the steel thread is stuck in the aluminium head? I never got around to trying this but I had a plan which was to try an alum bath to rot some nasty old pedals out of some not too shabby aluminium crank arms that they had become seized into.
I was thinking about this, I know of the many benefits of alum and have a container of it in my bathroom cabinet. Naturally when looking over the thousand ways to pull a dead bolt the mention of alum interested me. That could be a unique cop out for this.. Maybe after pulling the head I could use some chemistry to simply wipe the plug metal out. Would be kind of an impressive fix too.. Especially after the magic of dry ice failed. Coolant temperature isn't exactly what it should be anyway so perhaps pulling the head might reveal something related.. Funny how the stuck plug is the one closest to the tstat outlet to the radiator, generally that would be the hottest cylinder since that's the last to get the coolant. The first was definitely the easiest to pull, this is what you'll get if you leave the plugs in there for 13 years people, don't do that.
 


Frankenstein

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#12
The plug after 2 deep cuts and a 3rd partial and more of everything still refuses. The threads started getting gnarlled from prying, it's a lost cause, time to just helicoil it. Order placed for the kit should see it Monday.
 


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