2004 GT MT, I just replaced the plugs and wires. Used NGK wires and plugs. I have read a lot on this forum and the job was not too bad (thanks all) I did not use a torque wrench so I am wondering what is going to happen if I over torqued the plugs.

Also, the reason I did this was because all of a sudden the engine could hardly start moving from first gear. Very rough and NO power. 2 of the plugs were white and damaged at the tips, the others just looked used. The coils should be here tuesday and will be replaced promptly. Any info is welcome

Thanks in advance.

 

hand tight, then another 1/4 turn should do the trick.
Make sure all plugs are on properly.

Also, there are other threads regarding this.

 

First post...welcome. You're about to meet TeamRX8, but don't let that bother you.

Worst thing that can happen from overtightening plugs is stripping the threads in the engine. Second worst thing is that you may have trouble getting them out next time. Hope you used anti-sieze, or at least a couple of drops of oil, on the threads.

Ken

 

.

 

Overtightening may also deform the housing when it expands (heat)... That's less fun to deal with. Same happens, to a greater extent, when somebody fits some other rotary plugs without proper washers\spacers\care\brain\whatever.

 

To overtighten spark plugs to the extent where you would have to be concerned about possible detramental effects, you'd really have to put quite a bit of effort into it. Most likely, if you weren't straining yourself completely, you need not worry.

 

buy a freaking torque wrench.

 

+1 on that ^

 

A normal torque wrench will also work.

Ken

 

No necessary or adviseable for new NGK plugs:

http://www.ngksparkplugs.com/pdf/TB-...1antisieze.pdf

 

Wow! I've never seen that before. NGK is in the business, so they should know.

I don't think I've ever seen a spark plug that did not have shiny threads, either. I've never broken a plug, though.

Ken

 

the cluelessness doesn't end there


https://www.rx8club.com/showpost.php...89&postcount=9


https://www.rx8club.com/showpost.php...1&postcount=10


thanks for playing the repost game, better luck next time though probably not ...

 

And yet Mazda gives a torque spec in the shop manual.

Do the instructions on the side of the box apply to re-installing used plugs using the old washers? Or just new plugs with fresh crush washers?

Ken

 

Thanks everyone. All the replys and knowledge are much appreciated. As for the "buy a freakin torque wrench". Thanks and in 40k I will make sure to have one.

 

The installation instructions on the box apply to the new plugs in the box, obviously taking into account the new crush washers on the new plugs.

Re-installing old plugs with used / crushed washers cannot be done under the same instructions. Attempting to turn used plugs to the same degree after seating will result in overtorquing them, as there is little crush left in the used washer. In this case, I would use a torque wrench to factory spec. Also, since the factory coating has been compromised, I would also apply a little anti-seize to used plugs for reinstallation.

 

I expect to keep using a torque wrench and anti-seize on both new and old plugs. Although I can't remember the last time I removed plugs from a car and put the old ones back in.

Another place I defy the official instructions is lug nuts. Having been stuck a couple of times with rusted-on nuts, I always put a drop of oil on the threads and on the tapered seat. Never had a problem with that.

Ken

 

maybe we can get a moderator to change the title to ...

DIY: How to be a bunch of numnuts having a conversation thread where it is not permitted.