Best way to use a spark plug thread chaser?

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This is about the Dakota in my signature. I have to change out my spark plugs tomorrow. I did a tune up not long ago but now I have valve cover gasket leaks and I can smell hot oil when I shut off my engine. Tomorrow I will be changing the vc gaskets along with new plug wires and plugs. I do not know just now if the plugs are damaged, but I had a no-start problem this past Sunday so I am changing the plugs and wires for peace of mind and to be sure I fix the vc gasket problem correctly. I remember the new plugs went in pretty tight when I did my most recent tune up. The old ones were tight to remove as well, I was praying they were not stripped. I believe the tightness may have been from my liberal use of anti-sieze over the years. I have since learned about spark plug thread chasers and picked up one at AAP today. I can't find much info on using it though, other than to "thread it in and turn it back out". Some say use lubricant on the chaser but what kind? WD-40? Kroil? Spray silicone from a can? I also read to put a little grease on the chaser's threads to trap the particles it cleans out. I want to do this right without stripping the spark plug threads. My engine is old school Mopar, it has a cast iron block and also has cast iron heads. Any info on the chaser technique is very much appreciated. Thanks for your help.
 

JHZR2

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Interested in this too. Bought one a while back, but can't figure a good way to use it in deep-set spark plug holes like in dohc engines.
 
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CA
Problem: spark plugs left in too long. The solution: - Loosen the spark plug 1/2 a turn (or 1 turn). When you meet resistance. STOP! - Spray PB Blaster or WD-40 down there and let it work its way down the threads. - Then turn the plug CW and CCW. - Work it back and forth and back and forth. Don't hurry. - Eventually the plug will come out. I don't like the idea of a thread chaser much. I'd say use grease on the chaser, to try to catch the shavings. Load it up with grease. If you really have a choice try to get the piston close to the top, with the exhaust valve still open, and use a vacuum cleaner with a tube attachment to try to get the rest of the shavings out of combustion chamber. Here's a novel idea: get some of those tiny strong magnets from China. Put a few of them on the end of the tap. Should catch the cast iron bits. Could epoxy them to the tip if you're worried about losing one. I see a 12.5mmx1.5mm on dx.com. 20 for $10.13. Or, consider a spark plug back-tap.
 
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Originally Posted By: spackard
I don't like the idea of a thread chaser much. I'd say use grease on the chaser, to try to catch the shavings. Load it up with grease.
The stickier the better.
 
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3,619
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Clermont, Florida
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Thanks for the info. I will update here how the chaser worked. I think it's probably a good idea to chase the threads, my engine is 13 years old, I have put plugs in it probably 5 or 6 times, I always use anti-sieze and have never cleaned the threads. To be honest about it I never heard of a chaser until recently.
 
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A thread chaser is nowhere near as sharp as a true thread tap, it wont cut into the iron without some serious effort it just cleans the carbon, junk and rust (iron head) of the threads. There should be no metal particles dropping into the cyl anyway as you are not "cutting" threads just a little carbon which will be blow out the first crank of the engine. You can put a bit of grease on the chaser but don't get to OCD about it. If I use a chaser i just use a little engine oil then disconnect the ignition and crank it over a couple of turns with the plugs out. If you were cutting new threads for a timesert, etc then yes plenty of grease. The 18mm end (most have 14mm and 18mm) was originally for Ford 18mm plugs but its the same thread as O2 sensors. For smaller plugs you can make one easy enough by dremeling 3 equally spaced lines down the threads. A dremel cutoff wheel x2 together is just the right width, cut them about 1mm deep.
 
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Well as it turned out I was unable to use the thread chaser. It takes a 13/16" socket to turn it and my spark plugs have heat shields on them that are too small for a socket that big. So I just used an old toothbrush and sprayed it with Kroil, stuck it down in each spark plug hole and cleaned the threads the best I could with it. Then I wrapped a shop rag around the handle of the toothbrush and wiped out the residue from each plug hole. The old plugs came out fairly easy and the new ones went in much better than the last set after I had cleaned the threads and only used a very small amount of anti-sieze on just the first few threads of the new plugs. I have now learned that just a little dab will do ya on the anti-sieze. The new plugs started and threaded in a whole lot easier than the last set did. I did break off the plastic breather tube elbow on the right side valve cover so I will exchange the thread chaser for a new elbow and get a couple bucks back in change. Then I have to go to Autozone and pick up a new torque wrench. The torque on my valve cover bolts is 95 inch-pounds. My inch-pound torque wrench only goes as low as 120. Once I get back home I hope it does not take long to button it all back up.
 
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If I would have had problems screwing in the new plugs I would have taken your advice Trav. As it was, the first plug went in very easily and so did the others so I just used the toothbrush and Kroil method.
 
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Quote:
The torque on my valve cover bolts is 95 inch-pounds. My inch-pound torque wrench only goes as low as 120.
I have a feeling that this is NOT going to end well.
 
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Originally Posted By: Vikas
Quote:
The torque on my valve cover bolts is 95 inch-pounds. My inch-pound torque wrench only goes as low as 120.
I have a feeling that this is NOT going to end well.
Why is that? Torque spec per the Dodge Factory Service Manual is 95 in-lbs. I torqued it exactly like the book says. I checked it very thoroughly with the engine running and found no leaks whatsoever. What is wrong with that?
 
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Yes Kroil is some pretty good stuff, glad that worked out without jumping through hoops with tight plugs. I don't think Vikas saw you got another torque wrench that went lower than 120 in-lbs. It sounds to me like you did it right.
 
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