318SixPack

Stock Champion plugs are supposed to be .035" gap. New set of Champion Iridium have .045" (measured) gap and this says that is the gap too:
https://drivcat.com/overlays/part-de...pion%20Iridium
Which is right?

RocketMouse

I did mine last year sometime... the .35 sounds about right from memory... now I did the regular Champion ones....read somewhere that our old plants those worked well.
Now with a different material/type of plug, the gap may be different b/c any more narrow or wider depending on the plug... may cause it to not function correctly.
Of course it's a good time and cheap insurance to replace your wires and cap/rotor while you're at it.

Griffyorcono

The gap for the stock ignition system is .035. If you want to run .045 you'll need to upgrade your ignition system. I wouldn't recommend that much gap for the XJ though, as it isn't needed, ask Cruiser he will agree he's been saying he runs .036 on all his plugs for awhile now. I'll be running .040 and 89 octane which I have only heard is great for a cleaner burn but have done no real scientific testing on this yet.

Getting down to the real truth though and not my opinions, stock gap of .035 is going to be best for any ignition system and is how the system was built to work.

Note for 96 and under Kolak kit is ran with an MSD coil pack and I can quote that info from a rep at Kolak if you need proof.
"I bought the Kolak tuneup/ignition kit. It's excellent. I gapped plugs to 0.045 which is appropriate for the upgraded coil, plug wires, and Autolite Single Platinum Plugs the kit provides. My engine starts easier, runs smoother, has more low-end torque and high rpm HP, and it helped my gas mileage a little. The improvements are especially noticeable in cold weather, but also help in all weather. However, after installing Kolak kit (with wider than stock plug gap) I had to switch from 87 to 89 octane gas. The Kolak kit with 87 octane has a very rough idle. With 89 octane it idles and runs great. I notice more performance and gas mileage, especially in cold weather."
https://www.jeepforum.com/forum/f11/...5-ats-1551782/

Griffyorcono

I would agree this may be true, someone needs to call Champion and ask them.

318SixPack

This is what came from Rock Auto, and that is what they (and apparently Champion) specify as Iridium plugs for the 1996 XJ.

Difference because of material?

dave1123

I'm pretty sure the iridium tips of the center electrode is very tiny and should not be gapped because they can break if the tool hits them. Try running them for a while and see how they work out for you. Personally, I wouldn't waste the money on them since standard Champs last at least 50K before they need to be replaced, BUT they can be regapped at any time.

RocketMouse

yeah... just like a lot of things on our old plants... they don't require champagne class parts to keep running... just the ole tried and true stuff keeps' em going for a long time.

cpttuna

standard copper plugs and .035 gap are recommended

318SixPack

Okay I think I’ve solved the puzzle.
There are so many people out there saying you can’t change the gap on iridium plugs. But the Champion web page for these plugs has a caution that says to gap to .035”.
So, looks like I am going to be hunting a brass feeler set with .035 to minimize the chance of damaging the electrodes.

cruiser54

What? Brass? I've been gapping Iridium plugs with standard old feeler gauges for years. Where do you find this stuff?

318SixPack

I still haven't found a set that has. 035, going to just use the standard steel stuff.

cruiser54

I would hope so.