spark plug info

|V3nom| · 01-13-2012, 05:02 PM

trying to find out the correct gap and torque settings.

i seafoamed my car the other day before an oil change at 51k and decided to replace the spark plugs. no big deal right?

so i got out my 2008 M-car service manual, a huge 3 volume encyclopedia like set of service books for the kappa solstice and sky, and in volume 2 of 3 on page 9-26 it shows the spark plug torque at 12.5-17 lb-ft and the gap at 0.035-0.030 in.

straight forward enough but heres where it gets weird. on page 9-292, the spark plug installation procedure, it shows different specs. it says to tighten the spark plugs to 15 lb-ft and gap them to 0.45 in (im guessing its a typo and should read 0.045 in). what the heck?!

thats so confusing, why would they have two different torque and gap specs for the 2.0 in the same book? also when i look online, Sparkplugs.com - Application Search Results, it shows the gap at 0.044 in.

man gm blows my mind.

also on page 9-292 it says: "Notice: Do not coat spark plug threads with anti-seize compound. If anti-seize compound is used and spark plugs are over-torqued, damage to the cylinder head threads may result."

i was planning on using anit-seize too but im not sure anymore. says to apply dielectric grease to spark plug boot so i picked up some along with 4 autolite xp iridium spark plugs, which i have to de-gap from 0.050 to whatever the correct setting is.

so i have everything i need to do the job along with a torque wrench and spark plug gapper, have to de-gap first, but i need the correct specs first. if no one really knows then ill just do what page 9-292 says and torque to 15 lb-ft and gap to 0.045 in.

40rty · 01-13-2012, 06:30 PM

Torque spec by GM is 18in lbs for the lnf.Currently mine are at .32

Elff · 01-14-2012, 10:04 PM

I just changed spark plugs. I tried .035 first and my Sky did not like it.
Went back to .032 and it runs great.

the AC Delco 41-108s come gapped at .032

|V3nom| · 01-16-2012, 02:05 AM

Quote:

Originally Posted by 40rty

Torque spec by GM is 18in lbs for the lnf.Currently mine are at .32

well my service manual, by GM, says 12.5-17lb ft and 0.035in but it also says 15lb ft and 0.045in. this is crazy.

Gordon shamway · 01-16-2012, 03:15 AM

Last year of the end, I chenged my RL spark plugs.
Elff adviced me my RL much better 0.032 gap.
I checked new spark plugs gap was all 0.03.
Now my plugs gap is all 0.032, engine running condition is very smooth

Thanks Elff!
I recomend you should try this gap.

kudelt07 · 01-16-2012, 08:50 AM

+1 for the 0.032 gap. I believe my plugs are torqued to 15 lb-ft, and I've always used anti-seize... I guess we'll see if it actually does any damage the next time I change them out. 40rty, are you sure it says 18 in-lb and not 180? You could just about get 18 with your fingers.

wspohn · 01-16-2012, 09:31 AM

They no doubt tell you not to use antiseize compounds as you can easily overtorque the plugs with a friction reducer on the threads. Still, I always use antseize in alloy heads as the steel and aluminum tend to latch onto each other PDQ without.

|V3nom| · 01-17-2012, 08:51 PM

ill try without anti-seize and see how i like that. dont really want to take a chance over torqueing it and screwing up the threads. since my plugs are at .050 i need to degap them. any ideas on how to do that without messing anything up?

kudelt07 · 01-18-2012, 08:17 AM

If they are OEM style plugs, there is no trick (that I know of, anyway)... just be very careful. Though, if they are at .050, I suppose they probably aren't OEM plugs.

dipolley · 01-18-2012, 11:27 AM

I gapped mine to 44 once. My god what a horrible time that was. Everytime I got on it the car just sputtered. Just blew them right out. Pushed them down to 32 and all is good. But when ever I buy new plugs I have to degap them. I press them on a piece of hard wood and check the gap. It does not take much to bend them back into place, just be careful.

wspohn · 01-18-2012, 11:35 AM

Quote:

Originally Posted by dipolley

But when ever I buy new plugs I have to degap them. I press them on a piece of hard wood and check the gap. It does not take much to bend them back into place, just be careful.

I don't like this method as it risks pushing too hard and closing the gap excessively if you miscalculate.

I find that tapping the electrode on something hard (a vice, or hard casting on the engine, bolt head etc.) gently, checking after every tap with the proper feeler gauge results in much less risk. I hate using the notch tool found on many combination gauges to open the gap up again, as they act on one side of the electrode only, and would rather get down to the right gap carefully.

|V3nom| · 01-21-2012, 12:16 PM

yeah i just tapped my on my desk chair plastic arm rest and it worked. did it gently till i got it right. well i gapped mine to .045 like the book said and torqued to 15lb ft, which didnt feel as tight as i thought it would be, and i havent had any problems yet. havent really gone wot yet but i will once i replace my dp gasket.

SkyVue2 · 01-21-2012, 10:51 PM

Quote:

Originally Posted by |V3nom|

Well I gapped mine to .045 like the book said...

Now that you have the experience of changing the plugs
it will a lot easier when you pull them to reset the gap to 32.

flaxenfilly23 · 01-22-2012, 01:05 AM

Quote:

Originally Posted by SkyVue2

Now that you have the experience of changing the plugs
it will a lot easier when you pull them to reset the gap to 32.

Lol, ^ probably very true. My boyfriend and I regapped his plugs to .032 (his car was having some misfire issues) and afterwards his car ran like $#!^ any time he got on it. Talked to Vince at Trifecta and he recommended .028. Regapped them and its been running great ever since! I couldn't imagine if we had opened them up to .045! I honestly don't think it would have ran at all!

dipolley · 01-22-2012, 03:31 AM

Quote:

Originally Posted by wspohn

I don't like this method as it risks pushing too hard and closing the gap excessively if you miscalculate.

I find that tapping the electrode on something hard (a vice, or hard casting on the engine, bolt head etc.) gently, checking after every tap with the proper feeler gauge results in much less risk. I hate using the notch tool found on many combination gauges to open the gap up again, as they act on one side of the electrode only, and would rather get down to the right gap carefully.

I use a hard piece of scrap wood because the wood will give before the plug does. As opposed to using metal or plastic. This lessens the chance of degapping the plug too much because the plug will press into the wood, denting the wood. I can put a lot of presure on the plug and it only moves it a little bit. Plus I don't dent the plug by tapping it on metal.