94GrandPrix Posted April 12, 2015 Report Posted April 12, 2015 The owner's manual states that a .060 spark plug gap is recommended, but would it hurt/change anything if I use a .045 gap instead? If anyone asks why the .045 gap, it's what the spark plugs I'm planning on buying are pre-gapped to Quote
rich_e777 Posted April 12, 2015 Report Posted April 12, 2015 It will probably run like shit. Why would you want .045? The ignition system on the GM V6s is one of the best ones out there from my understanding compared to other make/models out there. What spark plugs are you planning to use? Quote
94GrandPrix Posted April 12, 2015 Author Report Posted April 12, 2015 It will probably run like shit. Why would you want .045? The ignition system on the GM V6s is one of the best ones out there from my understanding compared to other make/models out there. What spark plugs are you planning to use? Like I said, why the .045 gap? It's the pre-gap on the AC Delco plugs I was looking at. Guess that's why they recommend .060 in the owners manual right? Quote
redgrandprix Posted April 12, 2015 Report Posted April 12, 2015 i'm pretty sure all almost all later model gm vehicles fall under a tsb for .045" gap, those should be fine, i gapped mine around .028-.030 and it runs perfectly fine for regular driving without boost. Quote
RobertISaar Posted April 12, 2015 Report Posted April 12, 2015 a gap too small is preferable to a gap that is too big. too small might run oddly, but too large will fail to spark at high load, which does really interesting(bad) things to your secondary ignition, along with falsely triggering the knock sensor most of the time. that being said, a 3100 can run .080 and still not misfire under heavy load, especially with platinum/iridium plugs. I would just gap them to the correct spec and be done with it. Quote
pitzel Posted April 13, 2015 Report Posted April 13, 2015 I ran 0.06 for a few years and found that it was very hard to start in the winter. Practically impossible below -25C. Removing the plugs and re-gapping to 0.045 resolved problems starting at those temperatures completely. Intuitively this makes sense as the dielectric strength of air is improved with decreased temperature. Also, since re-gapping, high load low-RPM misfires disappeared. Anecdotally I believe the fuel efficiency decreased slightly, but I haven't taken it on a good 400-500 mile trip yet to definitely prove this. The manufacturer specified gap is printed on a sticker underneath the hood. IMHO, this should be obeyed unless there's a really good reason to want something different. Quote
SilverSport Posted April 22, 2015 Report Posted April 22, 2015 (edited) I see on many auto parts websites it is still .60... http://www.rockauto.com/catalog/x,carcode,1430618,parttype,7212 Bill Edited April 22, 2015 by SilverSport Quote
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