Spark plug gap

[Mike GMC]

When I put the plug in my 6.0 transplant engine, I looked up the plug gap.  The book said for 99 to 04, use a 0.060 gap and for 05 and up use 0.040 gap.  The 0.060 gap seemed huge to me, so I used the 0.040.  It runs fine, but I was wondering if anyone uses the 0.060 gap or knows why there is a different spec for the newer engines.

[00Silverado4x4]

I don't have a link or document handy but GM put out a notice years ago now changing the gap from .060" to .040". When I  changed my plugs on my truck I also set the gap to .040". You'll  be fine with that gap.

[txab]

GM changed the specified plug gap several years back for the older models. No longer is .060 recommended, .040 is the preferred. Buy plugs that are gapped to that spec.

[Mike GMC]

Good to know I used the right gap, but I wonder why the gap ever was 0.060?  Seem like a huge gap that would be hard on the coil packs.

[sefiroxx]

On earlier models, platinum plugs where spec'd at .06. Iridium plugs soon came out and they tested newer engines with the plugs and changed the gap spec. I believe they went back and checked the new gap spec on platinum plugs and found it to be acceptable ( Engine ecu was able to adapt).

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[Bad Bowtie2]

I'd gap 0.050" then!!!

 

HAHAHAHA!!