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Guest Message by DevFuse

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repair spark plug threads ?

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6 replies to this topic

#1 Guest_McBrat_*

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Posted 28 December 2002 - 07:45 PM

any fix you can do to spark plug threads without pulling the head?

#2 Guest_edrach_*

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Posted 28 December 2002 - 08:01 PM

I take it you've tried a thread chaser already. I believe that a heli-coil can be installed without pulling the head.

#3 Guest_Mike W_*

Guest_Mike W_*
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Posted 28 December 2002 - 08:53 PM

Put lots of sticky grease on the threads when tapping the hole (to pick up the shavings.) And/or use a Shop Vac with a smaller hose taped on the end to get into the sparkplug hole to clean out the shavings. Try not to lose the helicoil tang down the hole. Getting a tang out of the cylinder can be most unpleasant and leaving it in there not a good idea. One advantage of helicoiling with the head off the engine is that it allows you to file off the end of the helicoil after snapping off the tang. On rare occasions, the sharp burr left from popping off the tang will act like a self-locking device and cause the helicoil to un-thread from the cylinder head when you unscrew the sparkplug. I can tell you from personal experience that it sucks when that happens.

#4 Guest_GlCraigGT_*

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Posted 28 December 2002 - 09:04 PM

You defiantly want to use a helicoil, not one of the cheap spark plug hole repair kits. A lot of the time they will come out the next time you remove the spark plug. :(

#5 Guest_Surfhunter_*

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Posted 28 December 2002 - 09:44 PM

I just went through the same prob with my soob. I was going to try a helicoil, but after checking around I found a threaded steel sleeve that is easier to install than a helicoil. I did the repair with the head on the motor, they suggest that you remove the head, but it can be done in car if you are careful. I got my parts from NAPA, you need part # 2129: 3/4" Long, 14mm Spark Plug Rethreader and part # 2123: 14 mm Spark Plug Insert Tap. I think it was close to $30 for the parts. The Tapping tool is a combination reamer and tap, so it is a one step operation, no drilling required. The tool is also self-centering, so it is very hard to get the threads crooked as long as you keep downward pressure on it until it gets a good bite. Make sure the piston is all the way down before you start!!!! Once the tap part of the tool starts cutting new threads it will get very tight and tough to turn, because it is reaming and tapping at the same time. Use heavy grease on the tool, I used wheel bearing grease. I only greased about the bottom 1/4 of the tool, but put a good coating on it. As it turns and cuts it will force the grease and chips up towards the top of the tool. You will have to back the tool out several times to clean the old grease with the chips off and put new grease on. Go slow, I had to use a breaker bar on the tool once the tap part started biting real good, it got very tight. Once the hole is tapped, you just thread the sleeve onto your spark plug. Then you apply the thread locking compound (Loctite, comes with the sleeve) and thread the spark plug into the hole. Torque the spark plug to spec and you can drive it immediately. It does not say how long it takes for the Loctite to set, but I did not mess with the spark plug for 24 hours. If you have any questions feel free to email me. Bueno suerte!!!

#6 Guest_McBrat_*

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Posted 30 December 2002 - 09:29 AM

thanks for the ideas. well, this "new" motor I put in grizzly is the one with teh problem. when I put the plugs in (by hand) it went in cross threaded, so it was already that way, but I didn't noice it at first because it went in so easy. it even tightend up okay, but then I noticed it was crooked, so I backed it out and got it threaded the proper way, but it only snugs up, like the threads are stripped out. the plug worked it's way loose a bit over the last 500 miles. if I try and tighten it, it gets snug, then loose again. I snugged it, and it still runs okay, but I'm sure the plug is a little loose again....

I'm not in the mood to pull this motor back out again :)

#7 Guest_Mike W_*

Guest_Mike W_*
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Posted 30 December 2002 - 03:12 PM

I had my re-threading adventure with a Ford Escort. I got tired of the spark plug being blown out from engine compression. It was kinda cool how each time the plug was blown out, it made a new outward dent in the hood.

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