Setting Gap on Iridium Plugs (2011)

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comnoz said:
I see Denso is making an iridium plug with a platinum pad on the side electrode for wasted spark cars. I wonder why they don't use an iridium pad instead of platinum. Jim
Click to expand...

I imagine that it is because it would be a waste of the iridium; that is, presumably a platinum side electrode, having a short heat path/being in close proximity to the head - unlike the center electrode, runs at such a low temperature that there is absolutely no danger of the platinum getting vaporized by detonation/heat. That of course is why iridium can be run on the (long heat path) center electrode in boosted engines; it has a far higher melting point and thereby a greater tolerance for heat/detonation.

I've seen platinum center electrodes just disappear in turbo engines.
 
I'm running a Tri-Spark ignition, one of CNW's single coil conversions and NGK iridiums and they've been in for over 6,000 miles now with no issues apparent. I had them out the other day and all looked fine. I love them and I'm a compulsive spark plug changer normally.
 
I'm paying attention to yoose guys on this - especially on the boosted plug issues.
I intend to use copper core leads and R plugs. Apparently there is some issue on the spiral wound suppression leads as concerns the PowerArc ignition but was a few years ago when designer advised me on HT leads and plugs. Will ask again and let ya know what I'm told. I've used the spiral wound in many craft P!! to boats and vans and lawn mowers w/o any issue I could detect. Moss Motors has copper y/b Bumble Bee lead stock if ya care.
 
xbacksideslider said:
IMO, iridium plugs are the ultimate, I like the Densos over the NGKs because Densos have a smaller diameter center electrode and also the groove on the underside of the ground electrode.

They can explain it better than I can, so here's a link to Nippon Denso's Iridium site -

http://www.globaldenso.com/en/products/ ... tures.html
Click to expand...

From what I've read they're the same diameter, both 0.4mm?


On the subject of zero resistance caps NGK do make them but they aren't listed in all catalogues, resistance value is omitted from the part code

http://www.ngkpartfinder.co.uk/files/NGK_Spark_Plug_Covers.pdf
 
Slightly off the iridium topic but the platinum plugs are available as non resistor type. Slightly bigger electrode diameter but still a big improvement on standard.
 
So I fitted iridium plugs a week ago and set carbs again. Suddenly a week later bike farts and carries on misfiring at idle. I'm thinking, fuel starvation as I run only 1 tap or carb idle circuit issue. Quickly strip the carb, clear out any debris with wd40 then reroute the second fuel tap into the mix.
Still misfiring and carrying on. Rip of air cleaner and check Boyer in timing case for loose wires etc. refire. Same issue. Check coils 5.8 ohms each. Check wiring connectors. All good.
Yell at bike. Rip plugs out to see what I can see. Black and sooty but I know mixture is ok via gunston tuning plug.
Refit Autolite plugs. Purrs like a baby tiger.
Plugs not comparatable with my system????

Battery reads 12.59v Boyer unit with 2x 6v coils (I think)
 
Dkt26 said:
coils 5.8 ohms each.

2x 6v coils (I think)
Click to expand...

You should be getting a primary circuit reading of around 2.0 Ohms from a 6V coil.
 
I'm crap at electrics. I have a multi meter but to be honest, I don't know how to use it. I stuffed one pointer in the spark lead hole and one on either the + or - connector post.
How do I measure the ohms of my coil properly then?
 
Dkt26 said:
I'm crap at electrics. I have a multi meter but to be honest, I don't know how to use it. I stuffed one pointer in the spark lead hole and one on either the + or - connector post.
How do I measure the ohms of my coil properly then?
Click to expand...

Primary resistance = measure between the (+) and (-) terminals.

Secondary resistance = measure between either (+) or (-) and the plug lead terminal.

5.8 would be closer to a normal secondary reading but that should be kilo Ohms (Ohms x 1,000), so I think your (digital?) meter is reading 5.8 kOhms?
 
Back to the original question of GAP on NGK: You can add a dash number to the end of the plug number, like BPR7EIX-7 and the -7 specifies the gap in tenths of a mm.
eg, -7 = .028", -10 = .040, etc. I buy them pre-gapped like this for my supercharged Miata and my Norton. I love the Iridiums.
http://www.ngksparkplugs.com/docs/tech/ ... _plugs.pdf

Jaydee
 
Dkt26 said:
Refit Autolite plugs. Purrs like a baby tiger.
Plugs not comparatable with my system????
Click to expand...

Iridium plugs are resistor BPR type.

Are the plug caps and/or plug leads also resistor type?

If so, then there may be too much resistance for the ignition system to cope with.

Of course it could just be a dud plug?
 
I'm not sure bout my plug caps and to be honest, wouldn't know how to tell. At $22 per plug I sure hope it ain't a did plug!!
Thanks for your help LAB. I'LL look at it tonite
 
comnoz said:
Rick,

A dual output coil only has one secondary winding. Each end of that winding has a plug wire attached so when the field collapses one wire will be positive and the other will be negative.

That is why double platinum plugs were created. They have a small platinum electrode attached to the side electrode as well as a platinum center electrode. They are specified for cars using wasted spark ignition and dual output coils. Without two platinum electrodes the plug attached to the positive output of the coil will not get the benefit of the platinum and will erode quickly. Jim
Click to expand...



I know this is an old thread, but I have been reading up on this can't find the answer to this question.
Do 2- 6v coils in series, have this same result?
 
MichaelB said:
I know this is an old thread, but I have been reading up on this can't find the answer to this question.
Do 2- 6v coils in series, have this same result?
Click to expand...

No, not as long as they are connected + to - to + to -. Then you will want to check and make sure the polarity is correct.


Setting Gap on Iridium Plugs (2011)


left is right -right is wrong

ps -this is not a political statement!!!
 
Last edited:
So if I understand this correctly,
A dual output coil will fire one, one way the other reversed.
Where as, the 2- 6v coils, in series, will fire both the same, one way or the other.

To change the polarity would one simply reverse the hot and ground leads?
 
MichaelB said:
So if I understand this correctly,
A dual output coil will fire one, one way the other reversed.
Where as, the 2- 6v coils, in series, will fire both the same, one way or the other.

To change the polarity would one simply reverse the hot and ground leads?
Click to expand...

Yes
 
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