Seeking advice on spark plug gap

[jrcowboys]

Guys:

Background:

-Replacing spark plugs on 1999 Lincoln Continental
-Manual calls for .052-.054 gap
-Using Autolite double platinum APP104 for replacement
-APP104 are gapped at approx .040 gap out of the box
-Talked to local mechanic that I sorta trust and he did not recommend changing gap on double platimum plugs. He said they just install them at whatever gap they are set at out of the box.

What do you guys think? Note: I pulled one of the existing plugs out and it was gapped at .040.

JR

 

[mechanicx]

I don't see why you wouldn't regap these plugs. The engine will run smoother at the wider proper gap. They're really not that different from conventional plugs other than the little platinum tabs. The platinum plug gapper with the tapered gap measuring disk has a hole in it where you can you bend the side electrode. If you do it right the platinum tabs are not disturbed in anyway.

 

[dparm]

Multi-electrode typically should not be re-gapped. Single electrode SHOULD.

 

[Jeff_in_VABch]

You do need a special gapping tool (about $70) or use extreme care to regap the fine wire or fragile arc surface plugs.

On a low performance, low cylinder pressure engine like yours, the correct wider gap will make the engine run somewhat better. Will it run okay at 040 or even 030? Sure it will, but I wouldnt do it.

The lack of quality and attention to detail in non-professional services has become epidemic.

 

[Eddie]

Carefully regap the to recomended specs. As jeff stated the engine will run smoother

 

[Chris142]

Set the. Gaps. At Ford's spec

 

[dwendt44]

Back in the old days, there might have been a reason to gap at the small end of the scale(tip erosion). Now, with those 'little or no wear' plugs, the wider gap is the better choice.

 

[justinf89]

Gap it, carefully

 

[doitmyself]

Originally Posted By: justinf89
Gap it, carefully


Someone please describe the procedures for gaping AND measuring the gap on double platinums.

Somewhere I read that carelessly sliding a gap gauge between the double platinum tips could damage them. True??

 

[440Magnum]

Most double platinums are made by bonding a disk of platinum onto the steel substrate, so its theoretically possible to damage the Pt disk by forcing a gauge into the gap. But if you slide the gauge gently and carefully you should be fine. When bending the side electrode to adjust the gap, grip it on the side away from the tip.

 

[beast3300]

Gap to specs!

 

[mechtech2]

Most plugs that are made for a car are pretty close in gap.
These are way small. You may be able to open them up, but they may be at an angle, not square to each other.
But gapping is no problem to actually perform.
And you DO want the wider gap to help fire the mixture better.

 

[Vikas]

At least on the Japanese cars, NGK come pre-gapped or may be Japanese manufacturers select the appropriate OEM plug with necessary gap.

 

[GMBoy]

Gap to specs. The Autolite double plats are just copper plugs with platinum attached to both ends...easy to gap. They are good plugs, too. Never put a plug in ungapped except for Bosch +2/+4 style plugs and others with multi-electrodes. Fine wire Iridium you do have to be so careful or you will break it.

Points that others brought I know - but they are the right answers. Oh and I would question the quality of that mechanic or even mentions to a person to NOT gap a plug! A spec is for a reason.