Changing the Spark Plugs

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tannedstamina
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Re: Changing the Spark Plugs

Post by tannedstamina » Mon Apr 02, 2012 10:48 pm

Last question; they don't quite look like they're all in far enough... I finger tightened them and then gave them a 1/4 turn. Does anyone have any pictures to show what they should look like..?

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Re: Changing the Spark Plugs

Post by Deadly_Viper » Mon Sep 17, 2012 9:04 am

are the hotter plugs (RE7C-L) ok to use on a track day?
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Re: Changing the Spark Plugs

Post by warpc0il » Mon Sep 17, 2012 2:50 pm

yes
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Re: Spark Plugs

Post by ralferoo » Sat Sep 28, 2013 10:00 am

Snake wrote:Did a spark plug change today :)

14mm spark plug wrench
philips screwdriver
I know this particular post is quite old and the user is now an ex-member, but can someone confirm what socket the stock plugs require?

(Backstory: my coils failed about 6 months ago, at the time I bought new coils, plugs and leads from jp4mance, but only fitted the coils as I didn't have axle stands and the plugs were still a year off their service interval... fast forward to now when I still don't have axle stands, but the car has started slightly misfiring, so I think it's time to fit the plugs and leads as I don't want to have to replace the cat again!)

Anyway, I was just about to go to halfords to buy some axle stands and trolley jack (I'd rather go on the internet, but it's urgent as the car is now misfiring). Just before I went, I thought I'd dig out my bits to fit and check instructions on the web and noticed that my new spark plugs seem to have a 13/16" hex nut, but my spark socket is 5/8". And Halfords don't seem to have 13/16" sockets available.

I've seen varying instructions, some on US forums say 13/16", this post here says 14mm (which is 5/8"). If the originals are 5/8", I guess I can undo the old ones and put the new ones in finger tight and order the correct socket for next time. Or is it likely that the old plugs will also be 13/16"? (I'm trusting that Mazda replaced them 2.5 years ago on the 3rd service).

Is it likely the leads will make much difference on their own? If I get the axle stands now, I could still change the leads just not the plugs, but I kind of wanted to do them at the same time to minimise hassle...

BTW the new ones are NGK: RE7C-L and RE9B-T - I'm not sure if older makes are a different revision and so different hex size.

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Re: Changing the Spark Plugs

Post by warpc0il » Sat Sep 28, 2013 10:36 am

You need a standard 14mm sparkplug socket.

"14mm" is the diameter of the thread on the plug, and sparkplug sockets have a rubber insert to protect the insulation.

The A/F (across flats) measurement of the hexagon on the plug is just less than 13/16".
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Re: Changing the Spark Plugs

Post by ralferoo » Sat Sep 28, 2013 11:18 am

Seems a bit bonkers for them to measure the one part of the spark plug they don't contact with, but I'll take your word on it (and it seems to be confirmed as when looking again at the 14mm sockets, one of the reviews for a combined 10mm / 14mm socket mentions that the 10mm socket is used for 16mm hex nuts)...

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Re: Changing the Spark Plugs

Post by warpc0il » Sat Sep 28, 2013 11:27 am

The sparkplugs are described by their thread size, e.g. ours are 14mm plugs.

So it makes sense to describe the plug sockets by the plugs that they fit.
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Re: Changing the Spark Plugs

Post by ralferoo » Sat Sep 28, 2013 5:17 pm

warpc0il wrote:The sparkplugs are described by their thread size, e.g. ours are 14mm plugs.

So it makes sense to describe the plug sockets by the plugs that they fit.
Thanks for your help, also I just realised how awesome your forum name is! :D

So, I've attached a link to some photos, I won't attach them here as they're a bit big: http://www.angrysprite.com/public/sparkplugs/

What's interesting: one of the plugs is very corroded, unfortunately I didn't notice which one until I took the photos, but the front leading plug was very stiff. Also, all but one are very blackened. (I think 63 and 64 are the same plug, just from a different angle).

What's more interesting: the trailing and leading plugs were swapped on both rotors. I triple checked against the legends on the engine, the service manual and every webpage I could find as I couldn't believe it. Perhaps this is why they failed a year before their service interval. Perhaps this even lead to the coils being overloaded and causing them to fail in turn causing my cat failure. Whatever, another reason why I'm never trusting the dealership with my car again...

All in all, a very easy job. I spent the vast majority of the time working out where the front jacking point was and trying to figure out how to get my new axle stands under the car. In the end, I decided it wasn't possible as the jack didn't lift high enough. So, I used the factory jack tightened up to just under weight bearing and also put the wheel under the car as backup. In the end, I don't think I even got more that my arm under the wheel arch at any point, so I think my paranoia of being squashed as a bit too over cautious (for this job at least)... I guess it helps I bought a nice 10" extension bar and have long arms anyway!

One thing, I'd definitely recommend a universal joint. I bought one spur of the moment as I was already getting an extension bar and the plug socket. I don't think I'd have managed it without it.

Anyway, thanks to Spartacus for the original post and warpc0il for the extra info! Desperate to go out for a proper drive now. :D :D :D Just revved at high and low revs to test so far, seems smooth as a very smooth thing now! :)

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Re: Changing the Spark Plugs

Post by Markryan1981 » Thu Dec 18, 2014 5:07 pm

Copper Grease the right stuff to stop the sparkies from seizing up?
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Re: Changing the Spark Plugs

Post by DanBass » Thu Dec 18, 2014 6:11 pm

Yes, a dab on the threads.
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Re: Changing the Spark Plugs

Post by DB2626983C » Sun Apr 15, 2018 8:09 am

An old thread I know but.....do I change spark plugs with engine cold or warm?

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Re: Changing the Spark Plugs

Post by Rotary Potato » Sun Apr 15, 2018 8:14 am

DB2626983C wrote:
Sun Apr 15, 2018 8:09 am
An old thread I know but.....do I change spark plugs with engine cold or warm?

Dave

Either.

Less chance of burning your fingers cold tho. :)
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Re: Changing the Spark Plugs

Post by 13Black » Sun Apr 15, 2018 8:16 am

Shouldn't make any difference. I always do it warm only due to people driving the cars to me to get them changed. Decats as well. Roasting hot 500'C decats.


Edit: Hot potato on the case more so than tired Mr Melon.

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Re: Changing the Spark Plugs

Post by DB2626983C » Sun Apr 15, 2018 8:18 am

Many thanks guys....will do today while the sun shines....for once.
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Re: Changing the Spark Plugs

Post by PeteH » Sun Apr 15, 2018 9:35 am

Rotary Potato wrote:
Sun Apr 15, 2018 8:14 am
Less chance of burning your fingers cold tho. :)
If you're burning your fingers try buying colder plugs.......
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Re: Changing the Spark Plugs

Post by DB2626983C » Sun Apr 15, 2018 10:15 am

Nice emoji
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Re: Changing the Spark Plugs

Post by warpc0il » Sun Apr 15, 2018 10:18 am

DB2626983C wrote:
Sun Apr 15, 2018 10:15 am
Nice emoji

Full forum selection over there >>>>>
when you hit the [Full Editor and Preview] button
View more smilies
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Re: Changing the Spark Plugs

Post by DB2626983C » Sun Apr 15, 2018 10:27 am

:thumright:
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