To clear up some potential confusion about spark plug tightening specs...

[IamFODI]

You guys use toque wrenches?

🤣

One day I will be good enough at feeling crush washers crush

That day is not today

[Tbonem3]

You guys use toque wrenches?

[mrgizmo04]

Yeah I use 18 lbs-ft (around 24 Nm) on all plugs on all cars.

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[IamFODI]

Changed my spark plugs the other day and noticed something potentially confusing that I haven't seen talked about elsewhere. Also, this section of the forum needs content. So, I figured I'd post about this.


BMW TIS states 23 ± 3 Nm for spark plugs (ours are the M12):




I bought the NGK branded ones. Their boxes had directions specifying angles, not torque:



But it looks like those angle specs are for plugs with conical or ball seats, per the arrows in the illustration. Our plugs have flat seats with washers.

Also, NGK's guidance says to follow manufacturer's torque specs: https://ngksparkplugs.com/en/resourc...ut-spark-plugs

...Though they also list their own torque specs, which are not the same as BMW's: https://ngksparkplugs.com/en/resourc...g-installation. That page also lists torque specs for conical seat plugs, which seems to contradict the guidance on the box. Not sure what to make of that, if anything. For the torque specs for flat seat plugs with washers, I'd guess those are just conservative specs that are only to be used if you don't know the manufacturer's spec. IDK.


Either way, I used BMW's 23 Nm spec.

Interestingly enough, 23 Nm always turned out to be roughly half a turn from snug... #ShrugLife