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My civic has 100,250 miles and the service came up for the spark plugs. B124, I am reading and it says after replacing the plugs to torque it to 13 Lbs. The only torque wrench I have is minimum 15 LBS. Would this be too much torque? What are the chances that I strip the threads?

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    Without running a calibration, I wouldn't trust the the 15-lb minimum on your wrench to actually be 15 lbs.
    – Mark
    Feb 18 at 0:01
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    I'm not a mechanic but pretty-much everyone in my generation maintained his own car… and I never heard of anyone torquing spark plugs. Unless there's something special about your engine, the loose side of hand-tight should do the job. Feb 18 at 0:49
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    @RobbieGoodwin there's lots of science that says torque matters, and that people really stink at setting torques correctly. Feb 18 at 18:56
  • @Harper Thanks and again, unless there's something special about that engine, setting the plugs on the loose end of hand-tight will do the job. Who doubts that, why not cite an instance where a problem arose? Feb 18 at 22:43
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    ft-lbs or in-lbs? Torque wrenches (and specifications) come in both. Also, many spark plugs have torque angle specefications instead, especially if they come with antiseize coating on the threads (ngk typically do, and they are the brand I would suggest for a Honda). A torque angle specification will be more like "1/2 turn after the washer seats on the block" or something similar. Feb 18 at 23:05

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While it most likely will be OK, it is not worth the risk. If you do over torque the spark plugs and strip the threads you will regret it because it will be a big job to get it fixed.

Most mechanics will probably not use a torque wrench for changing the spark plugs, but they have had years of experience and know just how tight to make them. What you will be doing is definitely going past the manufacturers specifications.

If you do want to do the job yourself and dont want to get another torque wrench, use the torque wrench you have on another bolt until it clicks so that you get a feel for what the 15lb/ft feels like. Then tighten the spark plugs using what you feel is a little less force so that the torque wrench doesn't click.

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  • How about if it is under torqued? I found one on amazon with a 10LBS minimum but it jumps from 10lbs to 20lbs.
    – RobNav
    Feb 17 at 14:33
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    Typically for spark plugs, I don't use a torque wrench. My procedure for installing them is to lube the threads with anti-seize, then turn the spark plug down until snug (no real torque applied). Then, if the spark plug has a crush washer type sealing ring, I'll turn the spark plug another 1/4 turn. If the spark plug has an interference fit (no sealing ring), I'll turn it just a bit more past the "snug" to ensure it is fully engaged. That's usually about 5° worth of turn. Feb 17 at 15:04
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    @RobNav. You should be able to get a feel for when it it tight without over torquing it.
    – HandyHowie
    Feb 17 at 22:12
  • Agree with others, you should be able to get a feel for this, but you do have to be more careful about overtightening with an aluminum block than with a cast iron one.
    – Glen Yates
    Feb 18 at 17:18
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The lower and upper ranges of the torque wrenches are generally unreliable. With a bit of bad luck the deviation of the torque wrench is too large for the threads.

I'd consider getting a smaller wrench, as a min. 15lbs wrench is a fairly big tool.

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Given that there will be at least 5 or 6 full turns, the likelihood of stripping threads even at higher torques is unlikely. However, having changed thousands of sparkplugs, I've never ever used a torque wrench. Generally, plugs will have a crush ring, which is there for a purpose. Tighten, probably by hand, even, until that is reached, then turn another 45-90 degrees. That will allow the crush washer to do its job. I say by hand, as most stripping is caused by the first turn or two, when something is crossthreaded, and force is used to get it in.

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No - you'd have to stop tightening before the first click. If it clicks then you've over torqued it.

Another option is to "calibrate your elbow" by paying attention to how much force it takes to remove a spark plug. Using the same tool to reinstall should get you close enough, as long as you use about the same amount of force.

Two downsides, you're installing new plugs that may be less-smooth threads, and you're turning in the other direction which makes it harder to gauge. I work around the second when doing wheel lug nuts by always lifting up from the ground, and always kneeling.

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You can use any wrench really. The torque wrench just makes it quick and easy to get the right amount of force.

Foot/pounds: The foot part refers to the length of the handle, the pounds part refers to the amount of force.

So for your plugs apply 13 lbs of force 12 inches from the center of the socket. Or 26lbs of force 6 inches from the center of the socket. I find a simple hanging spring scale works well for the measurement part when I'm doing something outside the range of my torque wrench.

You can also use what one of my great uncles called the "jeweler's touch". As you tighten a screw thread the amount of force needed to turn it just a little more does not go up linearly. If you tighten the plug slowly you will feel a sudden jump in the amount of force required when all the threads are fully engaged. For the vast majority of applications that's where to stop. Practice on something else of similar size a few times and you'll get a feel for it. Like others have mentioned, most spark plugs need to be just a tiny bit tighter than you can get them with your bare hand.

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