Correct Iridium plug gap in NA MM is???

[Ozz]

I ask because since I have installed my Autolite XP104's there is a noticeable loss of power over the stock plugs (which had a .054" gap when I took them out at 33k miles). When I bought the XP104's I saw on a couple of the internet part stores had the gap for iridium plugs listed as .054" in a MM so I set them to .054".
In another post, RF Overlord mentioned that I should set them to .044". I have also seen .050" in other threads...

I would like to know others experience with iridium plugs before I regap them. Any insight as to why iridium plugs would need to be gapped less than platinum plugs (which have lower conductivity)? I just want to redo this once so I want to get it right.

One other thing - I used a little dielectric grease inside the ends of the plug boots. Is this acceptable? I noticed that the COP connectors do not really snap onto the plugs but rather just sit on the tip of the plugs. I'm waiting for a GMS COP connector group buy to upgrade...

THANKS!

[tddpop]

As far as I know, iridium plugs should not be gapped. They should come pre-gapped. They have a coating on the electrode that will get rubbed off. They also have small electrodes that break off and chip easily. I only have experience with Denso and NGK iridiums on my mustangs and they say on the box not to gap them. I don't know about the Autolites. If you experienced a power loss I would go back to stock replacements, and gap to specs. I had a 1997 Cobra that I put Denso's in, and I to lost power. I switched back to stock replacements and it felt normal again.

I personally have never used dielectric grease. It is supposed to make removing the plug boots easier, but I have never had a problem without it.

[Smokie]

My experience with the Densos IT20's (when N/A) was install them exactly as they came out of the box, I had no boot problem, no grease; just push 'em back over new plugs, they did snap on to plugs.

The positive results were slight but it could be noticed at idle and throttle tip-in.

[grampaws]

I don't use dielectric on th boots just change the plugs
regularly and never been a problem..I Have tried It with no noticeable
difference..The no click on the spark plug coils has me wondering
how much did you use..having to much might stop you from pushing
the boot firmly on?? A light coating on the inside of the boot is all
that is necessary..
I am not directly familiar with the autolite plugs the one I re-gapped
where bosch iridiums I was not impressed with them and went back
to motorcraft and NGK platinum plugs..using their recommended gap
and had no problem..

[Ozz]

The car seems somewhat better today after I regapped the plugs to .045" although I still think it was peppier with the stock plugs in it. I am not giving up on my $50 plugs yet...
As for the lack of snap, I thought this was normal with stock COP wires. I don't think they snapped onto the stock plugs either.

[warren]

The Denso folks suggest you gap are cars to .050 - the plugs come gaped to .044.
http://www.densoiridium.com/find_part.php?type=auto&autoYear=2003&make=MERCURY&action=Search
Stock- IT16, With tune/180stat.etc- IT20, Super Chgd. - IT22
However many leave them as is.
Use great care when you re-gap these as it is real easy to break the iridium
electrode.
These have a bigger spark ball and thinner iridium electrode made of a
different iridium alloy (95%iridium & 5%rodium) than any other for a more
complete burn.

Warren