Technical Tightening torque for spark plugs Panda 2016 1.2 69HP
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Technical Tightening torque for spark plugs Panda 2016 1.2 69HP
25Nm is too much and could seriously overtighten them if there is any grease on the threads.
The NGK recommendation is 15-20Nm. Most general purpose torque wrenches (particularly the cheap DIY ones) aren't accurate at settings this low, so proceed with caution.
With new plugs, and just a trace of thread lubricant, I'd not want to go over the lower figure. I've seen far more that have been overtightened than undertightened.
The screenshot below is taken directly from the NGK Europe website.
Be aware also that it's quite easy to cross thread them, and some folks have reported damaged heads as a result. I'd suggest using only light hand pressure to tighten until you are sure they're correctly seated, before reaching for a ratchet handle and torque tools.
Some folks (myself included) have fitted Iridium plugs; you won't notice any difference in performance, but they'll last least 60,000 miles, so a good choice if you're planning to keep the car awhile.
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Have you much experience of working on cars? I ask because if you are fitting new, out of the package, plugs then it's quite easy to tighten them by feel - I'll say more on that in a minute.
I'm mentioning this because it's not unusual to find some well meaning person, and I used to do this, has applied anti seize paste of some sort to the plug threads to stop them corroding in place and make removal easier later. The problem with this is that using a torque wrench then becomes meaningless because a torque wrench relies on the friction needed to install the plug for it to "click off". Put a lubricant of some sort on the threads and you'll overtighten the plug for any given setting of the wrench, possibly, in extreme cases, resulting in thread damage or even stripping of the thread. The plugs in the Panda have quite a long threaded length so, unless you cross thread them, thread damage is less likely than some.
For some time now, especially since long life iridium type plugs became popular, the manufacturers of the plugs have been applying an electrocoating (trivalent I think they call it?) to the threads - looks like chrome plating compared to the older type of plug - which is actually a sacrificial coating which, if a plug has started to corrode in place, will shear and release the plug when you start to unscrew it. So the advice these days is not to coat plug threads with anti seize, install them dry.
So, if you remove the old plugs and look closely at the threads and where they screw into the head and can see no signs of anti seize then using a torque wrench would be a sensible thing to do. If you do see antiseize traces - and often it's very obvious as copper based greases are commonly used and often applied "liberally" - then you should think of maybe reducing the torque wrench setting. The problem then becomes by how much? Well, it's just going to be what you guess, I'd say by a quarter, but who really knows.
These days though, not many people remove plugs at service time and clean and gap them as in days of old. Modern engines control their fueling so precisely that plug fouling is rare unless your engine is worn so burning oil or there is a serious fueling problem due to a faulty sensor etc. So plugs tend to stay in until the recommended change interval time is up - couple of years for a standard cheap plug and maybe 6 years or so for a ling life one. I'm mentioning this because if you have a new plug the sealing washer (crush washer) won't be crushed and this makes installing by "feel" quite simple.
To install a new, unused, plug with a new crush washer, by "feel" simply remove the old plug and wind the new one in by hand - don't use a ratchet, "T" handle, power bar, etc, just twist the socket (or extension) with your fingers until the plug is fully home with the washer seated between the plug shoulder and seating in the head. Now put a ratchet, "T" handle or whatever, on the socket extension and GENTLY apply a clockwise force. You'll feel the plug start to tighten up and resist your turning effort as the plug just begins to "nip" the crush washer between itself and the head seating. Now grip the ratchet, "T" bar, etc firmly and apply further tightening force. You'll find it tightens with moderate force being applied but then continues to turn for another quarter turn more or less with out any further increase in force being needed as the washer is crushed against the seating. This is a bit alarming if you've not done it before because it feels just like the thread is stripping! However, after this quarter turn, or thereabouts, of washer crushing the plug will have fully crushed the washer and the wrench will go "solid" - it would require a great deal more effort to now continue turning it, and if you did you'd strip the threads! You are aiming to fully crush the washer and stop turning when the plug becomes much harder to turn.
All that sounds a bit daunting doesn't it? However once you've got the feel for it, like with so many "how tight is tight" situations with vehicles, it becomes a nice and easy way to install new plugs and, arguably, actually safer than using a torque wrench where someone has previously applied anti seize? If you've never done this before You might like to do a "dummy" practice run on a scrap head if you have the luxury, but I used to teach this installation method to my students, as well as doing it the "proper" way with a torque wrench, and they all mastered it within minutes.
Of course once the plug has been installed the washer will remain crushed so you can't use this technique if reinstalling a used plug. However once you've done a good few installations this way you quickly develop a feel for "how tight is tight" and you can then use this sense of feel to tighten used plugs into place if reinstalling and not changing them for new.
PS, in theory you should fit a new crush washer every time you refit a used plug but in practice most people don't. Not many suppliers stock just the washers.
Well, I tightened many screws by hand and never broke anyone.
Actually, I used to do so with the spark plugs as well and didn't brake any. Somehow I started using torque wrenches with my BMW's some time ago, hence the question. 
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All my sparkplugs have been hand tightened until stop. Then one quarter tuned down. Then ignored until replacement. Never lubricate them with anything above sewing machine type oil. Most other things will burn until carboned.
I'd bet you'd probably be just fine tightening them by hand. As long as you have have "the feel" for it I think you're less likely to strip one by hand than just relying blindly on a torque wrench to click off?
I'm not saying torque wrenches don't have their place, I'd default to one every time on the likes of engines and gearboxes, also critical suspension and brake components. But I think there's an over concentration on their use in less safety critical tasks these days - no doubt fueled by the fact everyone looks for someone to blame/sue these days if something goes wrong.
I'm not saying torque wrenches don't have their place, I'd default to one every time on the likes of engines and gearboxes, also critical suspension and brake components. But I think there's an over concentration on their use in less safety critical tasks these days - no doubt fueled by the fact everyone looks for someone to blame/sue these days if something goes wrong.
