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broken spark plug...any tips? 900 1993

Hi everyone,

Changing the plugs in my 940na two weekends ago, I broke one off in the head. The only thing left in there is the threaded collar with the outer electrode on it. All the ceramic and the center electrode came out in my wrench. I've sprayed it with PBlaster a half dozen times now since it broke, and I still can't get it out with a screw extractor (also called an EZ/easy out, I think). Any thoughts on what I should try next? Heat? Power/air tools? Maybe it's time to give up and call for a tow? Thanks in advance.








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broken spark plug...any tips? 900 1993

Hello, I have had the same problem, just never in a Volvo. I used a torx socket for the big torx bolt on the olds cutlass front caliper. I can't remember what size, because I don't use it any more. What I do is, take a hack saw blade and grind the back off untill it fits into the hole of the spark plug. Wrap some tape around the end or use a small handle. Cut through the spark plug just untill you get to the threads. Then go ahead and cut the opposite side same way. Once you have cut through both sides, use a small punch and knock the threads loose. Then give it a good spray of lubricant and using a flat tip screw driver (must be wide enough to reach both cuts in the threads). A grinder is helpfull to make adjustments. I have better luck with the torx tool though. Take a spark plug and cut the end where the other is broke right below the nut. It is where the crimp is for the seal to the cermic plug. Bring that into a NAPA and get the torx that will not quite fit inside. Use you hacksaw tool again and make six shallow cuts that match up to the torx edges. You want the fit snug, but not so you have to drive it in with a three pond ball peen hammer, just enough to ease the plug base out. I uase a vacuum that has a reduction nozzel down to a 3/8 hose (lots of electrical tape), I use that to vacuum up most of the chips that come off from the saw. Use a coat hanger to wrap around the hose and then wrap it around the oil fill, leaving enough hanger to get the hose near the hole (about 1 inch), that gives you enough room to work and hands free of the hose. If all that doesn't work. Napa has a sleeve and tap kit for such problems. The debris though is a bit hard to remove from cylinder afterword. I use a 1/4 inch hose to vacuum out the metal shavings from the drill bit. I wish you luck. I had to do two in a Nissian Maxima. The customer towed it to three different shops before me. Everybody wanted to take the heads off. I can tel you I got the first one out with the hacksaw method in less than 20 min. The second took three differnet approaches before I ended up sleeving the hole. I ran fine when I was done. Once again, PATIENTS is the key. Pauli








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broken spark plug...any tips? 900 1993

I used an ez out, it work like a champ. drill out all the ceramic and place EZ out in plug and slowly turn it out.








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broken spark plug...any tips? 900 1993

It sounds like you already tried what the previous messages tell you to do,
even what was mentioned in previous threads (file & visegrips)
Are your EZ-outs the square tapered ones or the left threaded spiral ones.
The left threaded spiral ones might expand the thin wall of the plug to much even though they are a better tool.
I would try heating up the head as mentioned (running or flame) and try again with a bolt/screw extractor.
Last resort would be drilling when piston is at top of compression stroke (all valves closed in cylinder. High pressure blow out, then rinse out with water oil or something liquid and blow out again. You don't want metal shavings in there.

Good Luck
--
EJO now a 1993 944T 193K; ex '65 123S; ex '75 245; and ex '81 242GT; also Chrysler 2002 T&C and 2006 MINI Cooper








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broken spark plug...any tips? 900 1993

EJO, thanks for the help. My ez-out is the reverse threaded kind. It would seem to me, though, that you'd create the same expansive pressure by driving a square one in far enough to get a good bite as you do by twisting in the tapered threads, so I haven't tried anything square yet. I'm afraid I'll break off a file handle. The only heat source I have is a propane torch, which goes out after a few seconds of being held upside down (which is the only way to get the tip down in the hole) and is therefore pretty useless. I do have an electric soldering iron, but doubt that would get things hot enough. If I heat it up by running the motor, is there anything to watch for/be careful about while running on three cyl with #2 open to the elements? I would assume it'd have to run for a good 10-15 min to heat up this area since only the adjacent cylinders are firing, no?

I can't shake the feeling that this is headed towards me drilling the #%*% thing out...how do I tell whether I'm at the top of a compression stroke or exhaust stroke? Do you have to take off the valve cover and look, or is there a trick? Thanks everyone, I'm starting to get in over my head here and really appreciate the help.








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omg, I got it...long step-by-step for future reference 900 1993

In the hopes that this will help somebody else someday, here are the steps I had to go through to get this broken spark plug out. First, a quick recap: #2 plug was snapped off inside the cylinder head. Hex head, ceramic insulator, and the center electrode all came out with my plug socket, leaving just the threaded sleeve with the outer electrode still screwed in. I was using a regular 3/8" ratchet with a fairly long cheater bar on it when it snapped. This was on a car I had just purchased, and the plugs were only a couple years old, but the thing was frozen solid.

The crucial tool here is a size-5 screw extractor, known colloquially as an ez-out. It's basically a tapered, reverse-threaded drill bit. Stick it down inside the hole, and as you turn it counterclockwise, it screws itself in and bites into whatever you're trying to get out (they're meant for bolts with broken/rounded off heads that you then drill down through the middle of). I got mine at Ace hardware for about $4. The company that makes it is called Hanson, but I'm sure there are others. The end you attach your tools to is square, and it fits a 3/8" drive extention perfectly (though you have to put it on upside-down). Use a large crescent wrench to turn the assembly by clamping onto the male end of the extention. A 6" extention works well in this car. On a n/a car, you'll have plenty of room to work...turbos, good luck. I don't like the file/vise-grips idea that's mentioned elsewhere because I was afraid I'd break the file.

Mine was either corroded, cross-threaded, or over-tightened (haven't figured that part out yet) to the point that it wouldn't budge using only the above technique. I sprayed it with PBlaster 10 times over the course of three weeks and it still wouldn't move. Finally, I replaced the other three plugs, making sure to chase and clean the threads, which were a mess, then started the motor on three cylinders. NAPA sells a combination 14/18mm spark plug thread chaser for $7...you'll be amazed at how much crap comes out. Make sure you take your ez-out out of the dead cylinder before you start the car or it'll go flying. Also make sure your garage doors are open and your cigarettes are out because there are going to be gas fumes everywhere. It's also going to be really loud. Start the car and let it run for a few minutes. Turn it off and give it a shot of penetrating oil. At this point, I started using Deep Creep instead of PBlaster...who knows which one actually did the trick. Now spray the hole for several seconds with freezing spray, which you can get at Radio Shack for around $8. It's used for testing circuit boards. Temperature shock of the different metals (aluminum head/steel spark plug) to break the corrosive bond is the theory here. Give it another good, soaking shot of oil. Put the ez-out in, tap it gently a bunch of times with a hammer, take it out and spray the hole again with Deep Creep. Let it sit for as long as you can stand to wait, then put the ez-out back in with the extention and try to actually turn it out with the wrench.

I had to repeat this heating/freezing/tapping cycle three times before it finally gave. I waited about a half-hour or so between tries to let the different parts come back to equal temperatures. I feel pretty confident saying that eventually it WILL work if you're patient. Might have to give it an overnight to really let the oil soak in. I never had to use a cheater bar on the crescent wrench, and once it broke free, it was a real bear, but it got progressively easier to turn as it came out.

Hope this helps if somebody else gets stuck with the same situation.








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omg, I got it...long step-by-step for future reference 900 1993

Brilliant: I especially like the use of the freeze spray, which will likely work on a lot of stuck components such as brake lines, etc. To the FAQ.








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broken spark plug...any tips? 900 1993

I feel for you.
Luckily I have never had to face this problem. There were some quite good posts i the past on this though, like this one:
http://www.brickboard.com/RWD/index.htm?id=431212&show_all=1

Make sure you vacuum/blow the debris out of the combustion chamber before you install the new one.

Erling.

--
My 240 Page







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