Pre-gapped sparkplugs

January 14, 2008 7:54 PM

Is there any difference in performance between pre-gapped sparkplugs (such as these) and ones that you have to gap yourself?

I'm going to be replacing my sparkplugs soon and I wanted to make sure that these pre-gapped plugs aren't a problem. Assuming the gap is correct I can't see any reason why not to use them, but I wanted to see if anyone else had any experience with these types of plugs. Thanks!

posted by Aanidaani to travel & transportation (7 comments total)

No.

Pre-gapped spark plugs became possible due to the increase in accuracy of production of spark plugs. The reason you don't need to gap them yourself with feeler gauges is that they can be made consistently enough that the gap can be set accurately during manufacture, and so the structure of the electrode made string enough to withstand any potential ill-treatment during shipping (the main reason you needed to check them anyway).

They are 'pre-gapped' as in 'the setting you'd be doing years ago has already been done for you'.
posted by Brockles at 7:59 PM on January 14, 2008

What Brockles said.
posted by knave at 8:08 PM on January 14, 2008

What Brockles said, two times.

That being said, however, it's very easy to gap plugs yourself. Plus, you'll feel all old-school and shit. But at the very least, you can buy one of those .99 cent gap gadgets and double-check the pre-gapped gap before you screw in the plug.
posted by Cool Papa Bell at 8:15 PM on January 14, 2008

That being said, however, it's very easy to gap plugs yourself.

On the more traditional style ones, yes. The clever, 2 or 4 electrode ones are a little tough, though. No straight edge to speak of and no way to get into it. Then you HAVE to trust the gap...

(I checked 'pre-gapped' plugs for years before I believed them. I think I gave up after finding 100% accuracy after trying about a gazillion plugs, and mumbled something about 'Well, I'll trust you THIS time" begrudgingly. Old habits die hard...).
posted by Brockles at 8:34 PM on January 14, 2008

...you can buy one of those .99 cent gap gadgets and double-check the pre-gapped gap before you screw in the plug.
Maybe not such a good idea -- one of my motorcycles uses platinum electrode, pre-gapped plugs. The manual specifically warns about checking/changing the gap: apparently, the gap feelers can scratch the very thin platinum coating, which is bad for the plug.
posted by spacewrench at 8:51 PM on January 14, 2008

Ah, okay. I figure I'll still buy a gauge just to have in case I ever need it (They're cheap anyway), but pre-gapped seems the way to go. Thanks for the advice!
posted by Aanidaani at 9:05 PM on January 14, 2008

Note: It is highly advised you not try to re-gap iridium plugs. Apparently, the iridium is so fragile that re-gapping them can easily crack/damage them.

Note the second: I recently changed the plugs in my Maxima (my aching back) I used "pre-gapped" NGK platinums. I still had to re-gap two of the six. So, in my non-representative experience, it would still pay to, at the very least, check the gap.
posted by Thorzdad at 4:15 AM on January 15, 2008