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i just bought a set of four new spark plugs for the 111R. they are denso iridium. i can also post a picture if necessary. this is an original replacement part from lotus.

my question is if these spark plugs need to be measured and bend perhaps before install. :shrug:

please advise only if 100% sure. :panic:

thank you for your time :nanner2:
 

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If you need to adjust the gap on iridium plugs, do NOT use a traditional gapping tool or you can damage the plug:
Frequently Asked Questions: DENSO Iridium

Q. How do I gap Iridium plugs
A. Before attempting to gap any DENSO Iridium Power spark plug, please review the specification chart to see the factory-preset gap. In most cases your Iridium Power plugs do not need to be gapped. Even with small variations in the factory set gap the ultra-efficient firing power design will compensate for those small variations. Should you decide to re-gap your Iridium Power plug, use extreme caution as improper gapping may damage or destroy the Iridium center electrode or porcelain center. To increase the gap size: Step 1 Use needle nose pliers or spark plug gapping tool to bend the ground strap up to the desired height. DO NOT LET THE PLIERS OR GAPPING TOOL TOUCH THE IRIDIUM CENTER ELECTRODE OR PORCELAIN. Step 2 Re-check the gap with a calibrated gapping tool. To decrease the gap size: Step 1 Use the same method as above, however bend the ground strap down to the desired height. DO NOT LET THE PLIERS OR GAPPING TOOL TOUCH THE IRIDIUM CENTER ELECTRODE OR PORCELAIN. Step 2 Re-check the gap with a calibrated gapping tool. WARNING: Failure to follow these directions may permanently damage the spark plug. Note: Never use a round gapping tool to check the gap or to increase or decrease the gap setting.
 

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Densos are not OEM, but work fine. IK24s for SC'ed engine work well. As mentioned, no need to regap in most cases...

Best,

Phil
 

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... Re-check the gap with a calibrated gapping tool. ... DO NOT LET THE PLIERS OR GAPPING TOOL TOUCH THE IRIDIUM CENTER ELECTRODE OR PORCELAIN. ...
I don't know of any standard spark plug gauge or gapping tool that would not touch the center electrode in the process of measuring or setting the gap. Here are some examples of typical gauges and gappers:
KD Spark Plug Gauges
Denso's instructions seem impossible unless you get an optical device for measuring the gap. Anyone know what Denso had in mind?
 

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I don't know of any standard spark plug gauge or gapping tool that would not touch the center electrode in the process of measuring or setting the gap. Here are some examples of typical gauges and gappers:
KD Spark Plug Gauges
Denso's instructions seem impossible unless you get an optical device for measuring the gap. Anyone know what Denso had in mind?
I use one of these to measure the gap on my Denso Iridium plugs


This measuring device won't damage the center electrode that is almost needle thin.

If i need to reduce the gap, i just simply bang the electrode very gently against a piece of wood and re-measure. If i need to increase the gap, i use needle nose plyers. It doesn't take much strength to bend the electrode to the proper gap, so do it very gently.
 

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I use one of these to measure the gap on my Denso Iridium plugs


This measuring device won't damage the center electrode that is almost needle thin.

If i need to reduce the gap, i just simply bang the electrode very gently against a piece of wood and re-measure. If i need to increase the gap, i use needle nose plyers. It doesn't take much strength to bend the electrode to the proper gap, so do it very gently.
That is a standard feeler gauge (feeler meaning it touches), and it will touch the center electrode unless you are trying to eyeball the gap relative to the feeler gauge. Denso explicitly says that it should not touch the center electrode at all. Of course, they probably just used more extreme wording than necessary to protect themselves from people who touch the center electrode too hard.
 

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Discussion Starter #8
ok thank you guys. i have ordered the plugs from Lotus, so that is what i meant that tehy are the original. i asked them for the 111R, and this is what they gave me. my car is not supercharged and does NOT have any other engine modification !! so i guess i stick to the original measurement i just install them as tehy are, right ?


thx you guys !!! A LOT !!!
 

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ok thank you guys. i have ordered the plugs from Lotus, so that is what i meant that tehy are the original. i asked them for the 111R, and this is what they gave me. my car is not supercharged and does NOT have any other engine modification !! so i guess i stick to the original measurement i just install them as tehy are, right ?


thx you guys !!! A LOT !!!

I would still double check the plug gaps are within OEM specifications before installing.
 

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I don't know of any standard spark plug gauge or gapping tool that would not touch the center electrode in the process of measuring or setting the gap.
It says: "DO NOT LET THE PLIERS OR GAPPING TOOL TOUCH THE IRIDIUM CENTER ELECTRODE OR PORCELAIN. Step 2 Re-check the gap with a calibrated gapping tool. "

In other words, be very careful not to put any side loading on the center when bending the ground strap/electrode. You bend that with gapping tool (or pliers). To measure, you use a gauge between the center electrode and the ground strap.

The reason for this warning is that some gapping tools are used in such a way that they are a wedge that is slipped between the center electrode and the ground strap. You push the tool through the gap until the gap size lines up with the ground strap. This bends the ground strap by pushing against the center electrode. Since the center electrode in these plugs is basically a thin wire, you would end up damaging it.

Instead, you use the "hook" part of the gauge to hold the ground strap and bend it one way or another. It is a bit of trial and error to get it perfect - open it too far, and you have to close it; whoops, too far, open it back up, etc.

An example of the wedge type of gauge (okay for measuring, but don't use for setting the gap) is shown in the first photo. As a matter of fact, that particular tool has a lip on the top that is used to pry the ground strap up by leveraging against the center electrode.

The second photo is the better type of gauge/tool to use. The individual wires are the proper thickness for each of the gaps, and the part with the notches sticking out are used to hook onto the ground strap to bend it.

The third photo is an example of the wedge type combined with the hooks to bend the ground strap.

It's not reaially apparent in the photos, but the sides of the tools are tapered - thinner at one end and thicker at the other, and the numbers indicate the thickness.
 

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Traditional round gap tools are fine if you use them correctly....there is no reason to shove them against the electrode.
 

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Yeah but that's what most people will do. I'm sure that's why they warn against using them.
 

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Yeah but that's what most people will do. I'm sure that's why they warn against using them.
Exactly - Although I've used the sliding kind too when I needed to.
 
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