96 XLT 4.0 Spark plug gap

[CrownRoyalRacing]

Hey all,
I bought some Autolite Platinum plugs for a change. According to the website, the are pre-gapped to the .054 spacing required. When I pulled them out of the boxes, they were all over the place. Now the last time I changed the plugs, I re-gapped them to the .054 that is required, replaced with wires, and it ran like crap!! I went back to the auto-parts place and they said it was because I re-gapped them. So, I bought 6 more plugs, and installed them out of box verifying they were all gapped the same. (I took an avg and gapped them to that) The car ran fine after that. So my questions is, Do I gap them to .054 or do I take the avg (about .045) gap them to that setting, and install them?? I've heard both ways.........

Let me know what you guys think?!!?

 

[jd4242]

i had the same prob,i gap mine to around .060 but ive got the accel coil and 8mm plug wires and alot of mods but it seems to run fine,i didnt know what to do so thats what i did.

 

[CrownRoyalRacing]

Mine is all stock. I really don't want to have to do it twice so I'm hoping that someone here has ran into this before.

 

[CrownRoyalRacing]

Well, I installed them doing the "AVG" way and it runs fine.......I guess the gapping instructions underneath the hood are obsolete these days........

 

[Verno]

I've never trusted "out of the box" installs. I always gap plugs myself, regardless of what they are going in. The autolite plugs I put in my Ex the last time were pretty close to correct, but I gapped them at .054 I use a round gap tool, and once at the setting always rotate them towards the lower value to remove so as not to set the gap too wide, something Dad taught me years ago when I worked in his shop.

 

[Four0Sport]

autolites might say they are pregapped but by the time they get to the bin at the auto parts store they have been tossed around, jarred, and bounced enough to mess up the gap. always check the gap.. re-gapping shouldnt have any effect on how they perform, despite what the parts store guy told you.

 

[ranger7ltr]

New plugs pre gapped?

Recently I have bought Autolite 103's, Autolite Double Platinum, and AC Platinum plugs...All 3 sets were gapped around .045+/-.005 out of the box...

Gapping them to .054 seemed to misalign the outer and the center electrode...By opening up the gap the side electrode is slightly aligned away from the center electrode and not parallel to the center electrode as it was out of the box...

Not really convinced that this gapping is the best way to go but I tried the correct gap of .054 and then .044 on the replacement set and can't tell any real difference in performance...

Is anyone else seeing this problem?

EDIT: I was changing plugs trying to deal with a dead misfire in cylinder #2 which turned out to be an intake valve that had no pushrod opening it... After fixing that problem I installed the last set just to baseline the engine without an oil fouled plug...

 

[Tbars4]

...This is from Autolite...

Q. Do Autolite® spark plugs come pre-gapped from the factory?
A. Autolite® and all spark plug manufacturers offer spark plugs pre-gapped in the most popular gap sizes. Because of the many gap sizes required, no one offers spark plugs properly gapped for every application. Gapping has always been the job of the installer. You can be sure that the Autolite® spark plug recommended for your application has been engineered to meet the requirements of your engine, and that the gap can easily be adjusted as required.

...Just curious if there is a note on the side of your platinum plugs box...:scratch:

...I have seen previous discussions on this and they say do not use a slide ramp gap wheel to gap platinum plugs...

 

[CrownRoyalRacing]

I had originally gapped my Autolite Plat's to what I found to be the average when I pulled them out of the box. (.045) The X ran just fine. I just had all of the plugs back out yesterday for other maintenance and re-gapped them all to .052. I didn't even notice a difference. Someone should run a thread in which they run a tank of gas for different gaps and see how the performance/effeciency changes. It would interesting to say the least.

 

[CrownRoyalRacing]

And to answer Tbars questions, I have the Autolite Platinum box right here. On the back there is a note:
"Important Check Autolite spark plug catalog for proper application, torque specs, and gap settings. Set gab before installing."

Who has actually ever read the spark plug box anyway?!?

 

[Tbars4]

...I believe the spec book says .052-.056 for gapping your plugs...

...I believe Aldive has already done the test on various gaps...Do a search on here for "Milage Monster" by user "Aldive"...

...Here is the information for Autolite catalogs...
Q.How do I order Autolite® catalogs?
A. The latest Autolite® catalog, publication number ASP2002, can be ordered free of charge by calling our distribution center toll free at 1-800-890-2075, menu option # 5.

...Other useful info can be found at their website here...
http://autolite.com/

...And I know I am not the only one to read the notes on product boxes...Notes on the boxes and/or shipped with the product, are usually more current or product/vehicle specific than what are originally used for the general product brochure...

 

[CrownRoyalRacing]

lol.....I wasn't being critical......I was just saying that most of the people I know would never even think to look at the box. My Dad always taught me to look at the chart under the hood. What it said was what goes!! It's just funny how things have changed.

 

[dmc80]

just dealt with this yesterday, had motorcraft plugs in gapped at .045, and was missing, sputtering etc.Motorcrafts were only a year old in a rarely driven explorer. Pulled them and replaced with autolite xp's gapped at .055 and now runs great.

 

[CrownRoyalRacing]

Well, here it is about a week later and now all of the sudden I started getting a CEL P0306 Cylinder no. 6 misfire detected. This is very similar to what I saw the last time I changed the plugs. I pulled the coil wires to check the Primary and Secondary coil resistances. According to Dr Haynes.....Primary resistance should be .3-1.0 ohms and Seconday resistance should be 6500-11,500 ohms. Mine were the following:
Primary: .8 ohms x3
Secondary: 1-5 cylinders=14,800 ohms; 6-2 cylinders=14,990 ohms; and 4-3 cylinders 14,600 ohms.

I replaced the ignition coil and haven't gotten the CEL light again. So, to sum it up, ignition coil resistances should be considered when gapping your spark plugs. I guess it depends on if you want to spend the money for a new coil pack or not. I could have re-gapped them back to the smaller gap that I had before and saved $75. But I chose to do it the correct way, and now shouldn't have a problem with spark plug gapping for a while.

 

[Cobraguy]

The first thing you need to do is get rid of that Hayne's manual and find you a factory manual. Hayne's manuals are totally worthless. They are great for 95% of the information...but it's the 5% that will get you in trouble. Since you never know that that 5% is, none of it can be deemed trustworthy.

When detecting misfires, the secondary ignition side is just one piece of the puzzle. Compression and air/fuel ratio makes a big difference on the required voltages to fire a plug. i.e. a lean mixture is much more difficult to fire.

Also keep in mind, factory recommended plug gaps are there for emission purposes too. If you purchase the correct plug, it will be designed for the correct gap. Make sure your ground strap is parallel with the tip of the center electrode and your gap should be very close...yet it will give you the greatest firing surface to work with. You would think that all plugs fire from the center electrode to the ground. That may not be necessarily true in all instances. There are some pretty smart engineers that feel a DIS ignition system will allow spark to travel conventionally down the center electrode on one firing cycle, and do just the opposite on the wasted cycle. It's very interesting stuff if you are interested in that sort of thing. Worth the read.

 

[kendrellh]

New plugs pre gapped?

Recently I have bought Autolite 103's, Autolite Double Platinum, and AC Platinum plugs...All 3 sets were gapped around .045+/-.005 out of the box...
What u mean by intake valve

Gapping them to .054 seemed to misalign the outer and the center electrode...By opening up the gap the side electrode is slightly aligned away from the center electrode and not parallel to the center electrode as it was out of the box...

Not really convinced that this gapping is the best way to go but I tried the correct gap of .054 and then .044 on the replacement set and can't tell any real difference in performance...

Is anyone else seeing this problem?

EDIT: I was changing plugs trying to deal with a dead misfire in cylinder #2 which turned out to be an intake valve that had no pushrod opening it... After fixing that problem I installed the last set just to baseline the engine without an oil fouled plug...