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Setting Gap On Spark Plugs


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#1 hpracing10

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Posted 02 March 2010 - 01:12 PM

I am about due to change the plugs in my truck again. I have always used the AC Delco Iridium plugs but have never set the gap before. I am worried about setting the gap for my new plugs. The center electrode on the Iridium plugs come to a point at the end, so I took an old plug from a few changes back and just practiced setting the factory specified gap. Each time, I broke off the tip of the center electrode even while trying very carefully not to. It seems brittle and just crumbles off each time I put any amount of pressure on it. Will the center electrode on the new plugs be this brittle, and if so how do I go about gapping them so they are correct? Thanks

#2 ken1mod

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Posted 02 March 2010 - 01:14 PM

Plugs are pre gapped at the factory and should not be touched before installation.

Ken

#3 hpracing10

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Posted 02 March 2010 - 01:27 PM

Oh ok well thank you that was the information I needed. I was under the assumption that the gap was just set at the factory "universally" and it was required to gap them to what the owners manual says. I will continue to not touch them then! I am used to having to set the gap in all the plugs I run in my racecar so I figured it went for all applications, not just performance. Thanks again!

#4 brims

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Posted 02 March 2010 - 01:59 PM

Sometimes the plugs get screwed up in transport. Check them all to make sure they have the right gap. They sell a little metal disc at AutoZone and PepBoys and everywhere else that is a gap gauge. You need to have the correct gap for your vehicle, so I'd check what the plugs are compared to what they should be. If you gapped plugs for racecars, it's the same proceedure.

I recently replaced the plugs in my mom's Jeep, 2 of the 8 plugs weren't gapped properly.

Edited by brims, 02 March 2010 - 02:00 PM.

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#5 ken1mod

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Posted 02 March 2010 - 02:01 PM

I normally would agree with the last poster but the platinum/iridium plugs are just too fragile. I would just eyeball them. For the record, before i knew better, the plougs were all perfectly gapped from the factory.

Ken

#6 hpracing10

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Posted 02 March 2010 - 02:18 PM

Right, and I do have a little tool to gap plugs, I was just concerned about the little point on the center electrode of the Iridium plugs for my truck as compared to just the flat blunt center electrode on the plugs I use for my racecar. Thanks

#7 Gregorio

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Posted 02 March 2010 - 03:08 PM

Where necessary, spark plug gap is adjusted by bending the side electrode. No attempt should be made to move, bend, push or otherwise alter the center electrode. The dime store gapping tools should have a notched tooth that is used to grab the side electrode to accomplish this. The stepped portion of the tool is a measuring guage. It is not intended to be used to gap the plug by cramming it in between the electrodes.

#8 MS3DALE

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Posted 02 March 2010 - 03:11 PM

#03-06-04-060B: Information on New Spark Plugs and Gapping - (Jul 30, 2008)


Subject: Information on New Spark Plugs and Gapping


Models: 2004 Buick Rainier

2002-2004 Cadillac Escalade, Escalade EXT

2003-2004 Cadillac Escalade ESV

2004 Cadillac CTS-V

1997-2004 Chevrolet Corvette

1998-2002 Chevrolet Camaro

1999-2004 Chevrolet Silverado

2000-2004 Chevrolet Suburban, Tahoe

2002-2004 Chevrolet Avalanche

2003-2004 Chevrolet Express, SSR, TrailBlazer

1999-2004 GMC Sierra

2000-2004 GMC Yukon, Yukon XL

2001-2004 GMC Yukon Denali, Yukon XL Denali

2002-2004 GMC Sierra Denali

2003-2004 GMC Envoy XL

1998-2002 Pontiac Firebird

2004-2005 Pontiac GTO

2003-2004 HUMMER H2

with 4.8L, 5.3L, 5.7L or 6.0L V-8 Engine (VINs V, P, T, Z, G, S, N, U -- RPOs LR4, LM4, LM7, L59, LS1, LS6, LQ9, LQ4)



Attention: Please disregard the Set Gap Per Vehicle Specification statement on the side of an ACDelco® Iridium Spark Plug Box. The statement will be removed from the boxes in the future.


• A new spark plug has been released for use in the above vehicles. The new spark plug has an Iridium tip instead of the current Platinum tip. Due to the different tip design, the gap of the spark plug has also changed.

• The new spark plug, P/N 12571164 with AC Delco P/N 41-985, is gapped to 1.01 mm (0.040 in) when the spark plug is made.


Notice: The spark plug gap is set during manufacturing and should not be changed or damage to the spark plug may result. Any new spark plug found to not be properly gapped should not be used.

Edited by MS3DALE, 02 March 2010 - 03:16 PM.

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#9 MS3DALE

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Posted 02 March 2010 - 03:12 PM

#PIP3069C: Information - Iridium and Platinum Tip Spark Plug Maintenance - keywords 30K major minor preventative removal remove replacement tune up - (Apr 4, 2006)


Subject: Information - Iridium and Platinum Tip Spark Plug Maintenance


Models: All GM Passenger Cars and Trucks

with Iridium or Platinum Tipped Spark Plugs


The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
The information below was originally sent to all GM Dealers on October 14, 1999 as a DCS message. This information applies to all vehicles equipped with Iridium or Platinum Tipped Spark Plugs.

Recommendation/Instructions:
Iridium and Platinum tipped spark plugs are designed to operate under normal vehicle operating conditions for up to 100,000 miles (160,000 kilometers) without periodic maintenance. As stated in the owner's manual, maintenance needs may vary because of all the different ways people use their vehicles. As a result, more frequent inspections and replacements may be needed if the vehicle is operated in extreme conditions.

When no engine performance concerns are present, Iridium and Platinum tipped spark plugs should not be removed for periodic inspection and cleaning of threads, doing so may compromise the spark plug's ability to withstand their corrosive environment. The threaded area, although not sealed, serves as a protective environment against most harmful elements. Removing and cleaning spark plugs will introduce metallic debris and brush scrapings into the thread area which may further the corrosion process.

Chromate coated spark plugs should not be wire brushed or handled in any way once they are put in service. Chromium topcoats form a protective oxide on spark plugs that is not effective if scratched. Both coated and uncoated spark plugs will have the best chance of surviving a corrosive environment if they are left in position. Attempts to maintain spark plugs by removing them and cleaning the threads can actually create the corrosive condition that the procedure was intended to prevent.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

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GM accessories...Hood Deflector,Molded Mud-Flaps,Ventvisors,Catch-All Floor-Mats,Bedrail Protectors,BedRug Bedliner & Bedmat,and a GM Performance Parts cold-air intake.

2011 CAMARO 2SS/RS - LS3/M6 - Inferno Orange Met. - HURST short-throw - Roto-Fab CAI - Kook's LTs - CORSA exhaust - Black Bear tuned (playtoy!)
2012 CRUZE 1LT - Blue Topaz Met. - RS pkg.- Convenience pkg. (work car!)

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#10 USMdude

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Posted 02 March 2010 - 04:10 PM

I am about due to change the plugs in my truck again. I have always used the AC Delco Iridium plugs but have never set the gap before. I am worried about setting the gap for my new plugs. The center electrode on the Iridium plugs come to a point at the end, so I took an old plug from a few changes back and just practiced setting the factory specified gap. Each time, I broke off the tip of the center electrode even while trying very carefully not to. It seems brittle and just crumbles off each time I put any amount of pressure on it. Will the center electrode on the new plugs be this brittle, and if so how do I go about gapping them so they are correct? Thanks


The boxes use to say do not deviate gap. They do not say it any more but I have always heard to not adjust point style plugs....... And do not slide platinum plugs around gap gauges it will cause the coating to peal off, you should bend the platinum ones.

Jbo

#11 hpracing10

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Posted 02 March 2010 - 06:06 PM

Thanks for all the responses guys. I haven't ever gapped them in the past, and from the sounds of it I am doing just fine and I will not touch the gap on my new ones!




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