DIY re-gap factory spark plugs

[Brischke]

So a lot of people have mentioned (mainly xtreme revolution who has helped to point this out) that the spark plugs are gapped incorrectly from the factory.

I checked on mine which were way off (around .02) , took about 20 minutes to get them to normal (.035), haven't driven it around yet to test but am happier knowing its done. Here is a quick write up of this process:

Tools needed:
5/8 inch spark plug socket
T30 Torx Bit
Spark Plug Re-gapping tool ($1.99) at any autoparts store. Be careful to check the sizes make sense (I'm pretty sure the one I received was put together backward - notice .045 is smaller than .035)




Pop off engine cover




Remove the two torx screws
Wiggle out the spark plug boots




Not sure why this boot has so much dust



Remove the spark plug and re-gap as shown in this video

Spark Plug Gap - NGK Spark Plugs - Tech Video - YouTube

Reverse the procedure and put everything back together.

Have a few beers... not many things to work on yet with this car, might as well enjoy the small tasks.

[iCruze2]

Nice write up man

[Snuze]

Just a note - 0.035" is not "normal." The factory spec is 0.029" not 0.035." However many have noted improved performance with the higher than spec gap.

Great write up though, and I love the pictures. Very helpful.

[EcoCruzer]

Is it necessary to put anything on the plug threads when reinstalling?

[Brischke]

I'm not sure about the plug threads. I didn't because I figured it didn't make a difference from how they were in there prior to me taking them out.

[XtremeRevolution]

I posted the specs, which were pulled directly from AllData and GM's literature. It's .033-.037 for the 1.4T and .028 or .029 (I forgot which exactly) for the 1.8.

I would put some antisieze lubricant on them, but make sure you torque them down to 18lb-ft.

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[Snuze]

I posted the specs, which were pulled directly from AllData and GM's literature. It's .033-.037 for the 1.4T and .028 or .029 (I forgot which exactly) for the 1.8.

I would put some antisieze lubricant on them, but make sure you torque them down to 18lb-ft.

Sent from my Bulletproof_Doubleshot using AutoGuide.Com Free App

Interesting. I must have missed the post where the specs changed. My owners manual for my 2012 1.4T states gap is 0.029" which is what I'm going by. I don't know too much about AllData other than having heard of them, but are they correct, and has GM confirmed this?

[The Butcher]

Re-gapped to .035 this afternoon, three of the plugs were at .020 and one was at .019 which would probably explain why despite running 91 octane gas and adding a drop in k&n filter I still haven't been able to get my avg mpg above 26mpg... not sure how GM messed this one up but I'm really glad to have it fixed! It took me all of ten minutes and the car drives completely differently, no more extreme bogging down at low speeds or lagging at low rpm's and after an hour and a half of driving around tonight (50% city 50% highway) in AZ's 90 degree heat with the A/C on I'm currently averaging 31mpg, the highest I have EVER seen this car get since I've owned it! If you haven't made this modification yet it is a must, GM really needs to release a TSB about this issue...

[01sleeperZ]

The owners manual in my 12 Eco with manual states that the gap is to be 0.28 for the 1.4L engine and the 1.8L engine. I am concerned going to 0.35 when this higher number is not in compliance with my owners manual. Has anyone gotten Chevy to formally reply to this discrepancy between the owners manual and the Alldata & GM's other literature?

[XtremeRevolution]

Interesting. I must have missed the post where the specs changed. My owners manual for my 2012 1.4T states gap is 0.029" which is what I'm going by. I don't know too much about AllData other than having heard of them, but are they correct, and has GM confirmed this?

Yours says .029, the below says .028, AllData says .033-.037, and GM says .033x and .037x (they got one decimal point more accurate). The gaps are extremely inconsistent out of the factory.

The owners manual in my 12 Eco with manual states that the gap is to be 0.28 for the 1.4L engine and the 1.8L engine. I am concerned going to 0.35 when this higher number is not in compliance with my owners manual. Has anyone gotten Chevy to formally reply to this discrepancy between the owners manual and the Alldata & GM's other literature?

I'll call my dealership tomorrow and confirm with them. Going up to .035 will not have a negative effect. There are numerous people now who have done this with both the 1.4T and 1.8 and experienced great results.

The fact that many people have noticed a complete absence of extreme bogging, bad hesitation, and lagging throttle after increasing their gap to what I and a few others have confirmed to be the correct spec according to AllData should indicate that this is the correct gap to be using, not a random variety from .020 to .029 as they came from the factory.

If you walk into a shop tomorrow and have them change your plugs for no reason, they will gap them to .033-.037 because that's what AllData tells them to. I trust that AllData is much more current and accurate than the owner's manual, considering nearly every mechanic's shop in the nation relies on it.