Spark plugs backing out

lrt23 · #1 01-10-2016, 08:14 PM

I apologize if someone has posted a similar thread, but I have not seen it. Every so often some of my spark plugs back themselves out of their holes. The threads seem to be fine and they tighten back up without any issue (no cross threading, etc.). What can I do to stop this? I am thinking some blue locktight, but I'm not sure if this is a good idea.

2006_FX4 · #2 01-10-2016, 08:47 PM

That is not a good idea. Would not recommend anything like that on plugs. Are you sure you're tightening them to spec?

Krazy-baja · #3 01-10-2016, 08:54 PM

Make sure you have the right plugs to start with.
Other wise you are not tightening them enough

tomw0 · #4 01-11-2016, 06:56 AM

The 2.3 has 'tapered seat' plugs, as there is no washer on the plug to provide sealing. The taper on the plug seals against the cylinder head. The friction of that seal is what is used to keep the plug in place. If you do not tighten the plugs enough, they will back out over time (they sure won't get tighter...).
As they back out, they will OVERHEAT as there's no transfer of cylinder heat from the firing through the plug to the cylinder head. If the plug were tight, the threads would be in tighter contact(under tension) as would the taper where it is forced against the cylinder head.
Beyond the inconvenience of having to stop, to search for the plug when it blows out, there is also the possible pre-ignition (pinging) you can get with an overheated plug. Possible emissions problems also.
I think the torque is in the 10-15 ft/lb range. NOT super tight.
tom

lrt23 · #5 01-11-2016, 04:25 PM

I usually tighten them around 15 ft/lb. Autozone tells me I have the right plugs. This only happens like once every 6 months but I'd still like to get it right. I'm afraid of stripping the threads out of the head. Thanks for the advice guys

2006_FX4 · #6 01-11-2016, 05:19 PM

Quote:

Originally Posted by lrt23

I usually tighten them around 15 ft/lb. Autozone tells me I have the right plugs. This only happens like once every 6 months but I'd still like to get it right. I'm afraid of stripping the threads out of the head. Thanks for the advice guys

I have an electric ratchet that at full force will torque to 35 ft/lbs. I never put plugs in a full force but at about the 70% range on the trigger. So mine are always put in at ~20-25. Never had any back out or be too tight when removing. That's on multiple vehicles. I would think you just need to tighten them a little more.

barneycat11 · #7 01-11-2016, 05:24 PM

If your using never seize or a anti seize don't.

sheltonfilms · #8 01-11-2016, 06:22 PM

Quote:

Originally Posted by 2006_FX4

I have an electric ratchet that at full force will torque to 35 ft/lbs. I never put plugs in a full force but at about the 70% range on the trigger. So mine are always put in at ~20-25. Never had any back out or be too tight when removing. That's on multiple vehicles. I would think you just need to tighten them a little more.

Not to be off topic but what ratchet do you have? Milwaukee m12? That's the one I have and it is probably my favorite tool.

As far as anti-seize, I use it on all my vehicles' spark plugs with no issues. If plugs are torqued correctly they shouldn't come out.

tomw0 · #9 01-12-2016, 09:07 AM

I cannot say if it is needed, but if the cylinder head was made of Al and the plugs their normal Fe, the I would use anti-seize. For Iron to Iron, I never used it, BUT you want to make sure the head & plug threads are clean to insure that the torque is tightness, not just overcoming friction from crud on the threads.
You should be able to thread most plugs in using a piece of vacuum line onto the plug ceramic, all the way to where the plug seats on the head, and then tighten them that portion of a turn to apply proper torque.
Plugs back out if the threads are damaged in some cases. If you cannot torque the plug to the proper measure, and it keeps turning, likely the threads are too worn, and a repair is necessary. There are two brands of thread repair, and both names escape me. They can be used to ream out the old threads, cut new ones, and leave the head as it was before. Not exactly a $5 repair, either, so be prepared to cough up some bucks.
I always treat aluminum heads plug threads as if they were made of angel hair... Remove when the engine is cool to warm, not hot. Replace when cool, and use anti-seize AND a torque wrench.

heli-coil & timesert ... google works when brain does not search: thread repair kit

tom

Jeff_Birt · #10 01-12-2016, 09:22 AM

Sparkplugs come with an anti-seize coating applied from the factory (unless you getting some junk from China). There is no need to apply anti-seize unless you have taken the plugs back out (as the factory coating could have been scraped off.) It won't hurt anything to apply anti-seize to new plugs though.

And you guys using power tools to install plugs? That is just a bad idea from the get go. Plugs are relatively delicate and have fine threads AND many are hard to get to. A built in recipe for screwing things up. I suspect you also use your pneumatic impact gun to torque your lug nuts as tight as possible as well...

sheltonfilms · #11 01-12-2016, 11:24 AM

Quote:

Originally Posted by Jeff_Birt

And you guys using power tools to install plugs? That is just a bad idea from the get go. Plugs are relatively delicate and have fine threads AND many are hard to get to. A built in recipe for screwing things up. I suspect you also use your pneumatic impact gun to torque your lug nuts as tight as possible as well...

This tool isn't gonna screw up a spark plug or thread. Maybe a 14mm thread but not an 18mm thread.

2006_FX4 · #12 01-12-2016, 11:30 AM

Quote:

Originally Posted by sheltonfilms

Not to be off topic but what ratchet do you have? Milwaukee m12? That's the one I have and it is probably my favorite tool. As far as anti-seize, I use it on all my vehicles' spark plugs with no issues. If plugs are torqued correctly they shouldn't come out.

yes. It's my second favorite tool. Right behind my 18v 1/2 brushless impact.

----------

Quote:

Originally Posted by Jeff_Birt

And you guys using power tools to install plugs? That is just a bad idea from the get go. Plugs are relatively delicate and have fine threads AND many are hard to get to. A built in recipe for screwing things up. I suspect you also use your pneumatic impact gun to torque your lug nuts as tight as possible as well...

The ratchet works great. Never done any damage. Use it or don't, I really don't care. And as a matter of fact I do use my impact to torque lugnuts down.. With torque-sticks. There is more than one way to skin a cat Jeff.