Pre-Gapping Spark Plugs to 0.065”

[calisoundmix]

Just a quick question, are there any ill-effects of gapping new spark plugs at 0.065” and running them with the stock coil pack for a week or so?

I have a new Screamin Demon coil pack ordered but its backordered and won't ship until Monday. The reason I wanted to put the spark plugs in this weekend is because my brake pads are due for a change and I figured I'd might as well do both, since my Hawk pads came in today. Thanks!

 

[aldive]

You should be fine.

 

[calisoundmix]

so a followup, after gapping my new plugs to .065" i had misfire codes thrown on both cylinder 1 and cylinder 4 ( P0301 & P0304 ), took plugs out and it turns out they were gapped at 0.069", changed them back down to .065", put them back in and no more codes thrown.

however i have been lacking low end power and the engine "stumbles" at low rpm's, the check engine light still turns on at startup but is not giving any codes. is this just my old stock ford ignition having a hard time with the gapped plugs (new SD coil pack will be here thursday) or is this possibly a battery problem? (just had alternator re-maned 1 month ago), i measured the voltages and they are below.

Battery Alternator
12.25V 12.22V - After sitting Overnight
14.62V 14.88V - One min after startup

 

[gijoecam]

You've almost doubled the OEM gap... I can see that causing a misfire the same way running 200,000 miles on properly gapped plugs could cause the same problem. The spark is only going to jump so large of a gap...

-Joe

 

[CDW6212R]

The voltages are fine, the .065 gap is a hair too much(stock is .054) for running long with OEM coils.

How are the plug wires, those cause more trouble than spark plugs?

 

[gijoecam]

Why was I thinking the stock gap was .035? Must've been a brain fart..... Guess I'm confusing the lawnmower with my Explorer.

-Joe

 

[CDW6212R]

Why was I thinking the stock gap was .035? Must've been a brain fart..... Guess I'm confusing the lawnmower with my Explorer.

-Joe

Don't do that, just say that you were recalling the gap of your supercharged Cobra.

 

[calisoundmix]

forgot to mention that i replaced the wires as well, got a set of the magnecor's. i only mentioned the battery because when i'm sitting at a stoplight at night the lights dim slightly when it stumbles, if i lightly keep the gas going (~1200 rpm) it is fine 99% of the time.

thanks for the replies guys, ups shows the coil pack still on time for a thursday delivery, i just wanted to make sure i wouldn't cause any long term damage in the meantime with the engine stumbling, the ex has been good to me the past 100k miles and i hope to have it for many more.

 

[calisoundmix]

installed the coil pack during my lunch break and much of the lost power is back, however there is still a very slight idle problem, with the engine shaking likes it's misfiring, but so far no codes have been thrown. it doesn't "stumble" at all when accelerating, only when sitting at a stoplight about half the time. anything else to check besides the IAC? the computer has been reset by the way after the new coil pack was installed.

 

[Firestorm]

You may want to clean the MAF as well. Even though you're not throwing a code, I've seen this mostly as a combo cleaning with the IAC as well.

 

[calisoundmix]

MAF and IAC were cleaned 2 months, i use an amsoil ea filter so no oil to worry about dirtying the MAF up. I've regapped all the plugs down to .06" but i'm still getting misfires on cyl 1 & 4. I bought some seafoam and i'm replacing the fuel filter later tonight but i'm puzzled as to what this could be. it was running very good before the ignition overhaul and now it's sputtering, any ideas?

thanks.

 

[Firestorm]

After the seafoam and fuel filter are you still having the same problem?
If so, see what your fuel pressure is.

 

['97 V8]

why the large gap? Gap them to normal oem specs.

 

[Jakee]

Because he has a screaming demon coil pak and he want's to take advantage of it.

You may want to check all your plug wire connections. Make sure they feel tight, and if you find one that doesn't feel right, you can squeez crimp it to fit. I had this problem with the JBA wires I currently use. That's the only thing that makes sense to me because you didn't have this problem before, right? If you didn't have this problem before, don't look at things you didn't mess with yet.

 

[Turdle]

I'm not a fan of wide gaps.

 

[calisoundmix]

so i decided to spend the roughly $25 to get a new set of bosch platinum +2's hoping this would solve the misfire problem. (i know some don't like them but they had been working great the past ~60k miles)

and guess what? it did! all i can think of is that my low gearing (3.55) doesn't like having wide gaps at the low rpm's it runs at, so i will keep the +2's in unless i receive any more misfire codes, and on a side note for future searches, the new coil pack has improved my idle which is worth it for me. thanks for the help!

 

[CDW6212R]

Having plugs cause misfires is very common, even when "new" out of the box. That is why it isn't really the best idea to spend big money on such undependable parts.

Choose quality parts, but not the high cost specialty stuff, often you end up replacing them to hunt an issue. Spend big money on the plug wires, those are very fragile and easy to damage. Either buy the cheapest because you are about to sell the vehicle, or the best to keep it forever. Regards,

 

[djsk8r33]

dont plugs come pre-gapped at .055? or something close. i recently change out my plugs but i didnt gap anything. just a direct swap, i guess you could call it.

i told the autozoo idiot what kinda truck i had and i asked him for whatever was stock. i think it was motocraft gold? or something or other.

 

[aldive]

Plug gap should always be checked. I have seen great variety in new plugs.

 

[CDW6212R]

Ditto, they should come gapped, but always check them. They often are off a little.