Changing Spark Plugs.. Input Please
Thread Starter
Instructor
Joined: Apr 2009
Posts: 193
Likes: 1
Changing Spark Plugs.. Input Please
i am wondering if there is a general concensus for plugs.
i would like to know if there is a particular brand, heat range and gap that most use. i am not looking for some silly claim of additional power but just a good solid plug to run with my upgrades.
i have ac delcos in there now and they are a nice light brown but some of the diodes seem to be wearing away which of course is changing the gap on those affected.
also very important.. are we supposed to use anti seize on the plugs?
tks, dal
i would like to know if there is a particular brand, heat range and gap that most use. i am not looking for some silly claim of additional power but just a good solid plug to run with my upgrades.
i have ac delcos in there now and they are a nice light brown but some of the diodes seem to be wearing away which of course is changing the gap on those affected.
also very important.. are we supposed to use anti seize on the plugs?
tks, dal
Melting Slicks
Joined: May 2004
Posts: 3,017
Likes: 2
My tuner recomended TR6Ix..One heat range cooler..They come pre-gapped at .040 I believe. The car runs great, a little smoother idle..I would also consider changing wires to MSD superconductor..Good probability you will damage one of the stock ones getting them off..Use some dielectric grease on the plug boots to make them easier to get off next time..
Drifting
Joined: Feb 2006
Posts: 1,339
Likes: 1
From: Lake Delton (WI Dells) WI
second the MSD wires. I have them on my Firehawk and they are a nice wire that "snaps" on the plug nice. I used some other brands that basically just slide on the plug and one could never tell if they were on correctly. With those MSD's you will feel it "snap" on. I have also been using NGK plugs for awhile w/o any issues in my LS1.
Race Director
Joined: Nov 2005
Posts: 14,545
Likes: 1,532
From: Supporting the Corvette Community at Abel Chevrolet in Rio Vista, CA 707-374-6317 Ext.123
St. Jude Donor '08
I can not believe people are recommending using Anti-sieze on spark plugs. That is a HUGE 
. I have seen countless instances where a misfire code can be traced back to anti-sieze on the plug. GM does not recommend using it and neither will any good shop. It not only effects the torque value on the plug, but also the grounding of the spark plug body. Never use anti sieze on spark plugs, simply clean the area with compressed air proir to removing the plug and torque the new plugs to 15 LBFT max. 
Here is a little paragraph from GM's Service Info about similar chemicals:
Fastener Notice
Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque, grounds and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
. I have seen countless instances where a misfire code can be traced back to anti-sieze on the plug. GM does not recommend using it and neither will any good shop. It not only effects the torque value on the plug, but also the grounding of the spark plug body. Never use anti sieze on spark plugs, simply clean the area with compressed air proir to removing the plug and torque the new plugs to 15 LBFT max. Here is a little paragraph from GM's Service Info about similar chemicals:
Fastener Notice
Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque, grounds and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
Pro
Joined: Apr 2005
Posts: 702
Likes: 82
From: Ronkonkoma NY
St. Jude Donor '08-'09
I can not believe people are recommending using Anti-sieze on spark plugs. That is a HUGE . I have seen countless instances where a misfire code can be traced back to anti-sieze on the plug. GM does not recommend using it and neither will any good shop. It not only effects the torque value on the plug, but also the grounding of the spark plug body. Never use anti sieze on spark plugs, simply clean the area with compressed air proir to removing the plug and torque the new plugs to 15 LBFT max.
Here is a little paragraph from GM's Service Info about similar chemicals:
Fastener Notice
Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque, grounds and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
. I have seen countless instances where a misfire code can be traced back to anti-sieze on the plug. GM does not recommend using it and neither will any good shop. It not only effects the torque value on the plug, but also the grounding of the spark plug body. Never use anti sieze on spark plugs, simply clean the area with compressed air proir to removing the plug and torque the new plugs to 15 LBFT max. Here is a little paragraph from GM's Service Info about similar chemicals:
Fastener Notice
Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque, grounds and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
2027 Corvette Buyer's Guide: Everything You Need to Know!
Joe Kucinski
10 Things C8 Corvette Owners Hate (But Won't Tell You)
Joe Kucinski
10 Best Corvettes Coming to Barrett-Jackson Palm Beach 2026!
Brett Foote
Every Corvette Grand Sport Explained! (C2, C4, C6, C7, & C8)
Joe Kucinski
Grand Sport & Grand Sport X Launch Alongside All-New 535hp LS6 V8!
Michael S. Palmer
5 Reasons Bad Drivers Crash & 5 Ways to Avoid a Costly Mistake!
Joe Kucinski
7 Bolt-On Upgrades From Extreme Online Store to Level Up Your C6 Corvette
Pouria Savadkouei
Le Mans Master
Joined: Jan 2005
Posts: 5,611
Likes: 5
From: Thousand Oaks California
i am wondering if there is a general concensus for plugs.
i would like to know if there is a particular brand, heat range and gap that most use. i am not looking for some silly claim of additional power but just a good solid plug to run with my upgrades.
i have ac delcos in there now and they are a nice light brown but some of the diodes seem to be wearing away which of course is changing the gap on those affected.
also very important.. are we supposed to use anti seize on the plugs?
tks, dal
i would like to know if there is a particular brand, heat range and gap that most use. i am not looking for some silly claim of additional power but just a good solid plug to run with my upgrades.
i have ac delcos in there now and they are a nice light brown but some of the diodes seem to be wearing away which of course is changing the gap on those affected.
also very important.. are we supposed to use anti seize on the plugs?
tks, dal
The AC Delco Iridium plugs are very good.
Safety Car
Joined: Feb 2007
Posts: 4,684
Likes: 107
From: Opelika Alabama
My tuner recomended TR6Ix..One heat range cooler..They come pre-gapped at .040 I believe. The car runs great, a little smoother idle..I would also consider changing wires to MSD superconductor..Good probability you will damage one of the stock ones getting them off..Use some dielectric grease on the plug boots to make them easier to get off next time..
with the MSD wire's the stock wire's are crap! car runs better than it ever had after the new wire's!
Safety Car
Joined: Sep 2006
Posts: 4,364
Likes: 407
From: Greer, SC
I can not believe people are recommending using Anti-seize on spark plugs. That is a HUGE . I have seen countless instances where a misfire code can be traced back to anti-seize on the plug. GM does not recommend using it and neither will any good shop. It not only effects the torque value on the plug, but also the grounding of the spark plug body. Never use anti seize on spark plugs, simply clean the area with compressed air prior to removing the plug and torque the new plugs to 15 LBFT max.
Here is a little paragraph from GM's Service Info about similar chemicals:
Fastener Notice
Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque, grounds and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
. I have seen countless instances where a misfire code can be traced back to anti-seize on the plug. GM does not recommend using it and neither will any good shop. It not only effects the torque value on the plug, but also the grounding of the spark plug body. Never use anti seize on spark plugs, simply clean the area with compressed air prior to removing the plug and torque the new plugs to 15 LBFT max. Here is a little paragraph from GM's Service Info about similar chemicals:
Fastener Notice
Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque, grounds and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
Safety Car
Joined: May 2006
Posts: 4,288
Likes: 129
From: Providence Forge, VA
St. Jude Donor '08-'09-'10-'11-'12
Race Director
Joined: Jan 2004
Posts: 18,721
Likes: 708
From: Bergen County, NJ
That's what anit-seize was made for, and used by mechanics for a jillion years.
Drifting
Joined: Oct 2004
Posts: 1,790
Likes: 29
From: STL MO
St. Jude Donor '09-'10
I just spoke with my buddy who is an ASE certified tech for GM and he said you do want to use anti-seize on the threads of your spark plugs, just don't go crazy and get the product near the tip.
I always have and will continue to do so. NGK TR-55's gapped at .045
I always have and will continue to do so. NGK TR-55's gapped at .045
Last edited by Neumonic2002; Aug 8, 2009 at 04:01 PM.
Safety Car
Joined: Sep 2006
Posts: 4,364
Likes: 407
From: Greer, SC
I can tell you I used anti-seize it on my 2002 LS1 Z28 and put a lot of miles on that car after I put plugs in and never had an issue. I did only put a dab on and only on the threads. I also went with the NKG TR55's and probably will when the vettes plugs need changing.
Drifting
Joined: Feb 2007
Posts: 1,537
Likes: 1
From: Southlake Texas
First time I heard that. Without ant-seize how do you keep the plugs from fusing with the head? I have always heard that you need anti-seize especially with dis similar metals like steel and aluminum. Was that information incorrect? I could have sworn that the service manual for my 2002 Z28 LS1 said to put anti-seize on the plug threads before installing. I guess GM found that caused an issue later? Thanks for the updated information.
Also, plugs are cheap. Don't leave them in the head for 100,000 miles and you will not have a problem if they were installed correctly.
EDIT: For everyone using anti-seize on spark plugs (living in the 1960s?
), you might consider the recommendations of spark plug manufacturers. For example:"Champion recommends that you do not use an anti-seize compound, since one has already been applied to the plugs at the factory. Next, install the spark plugs finger tight and, it using a taper seat spark plug, use a ratchet to rotate 1/16 of a turn. If using a gasket seat type spark plug, after installing finger tight, turn 1/4 to 5/8 of a turn. If this procedure is followed, spark plugs will not back out nor will they seize in the cylinder head."
"NGK specifically states do not use anti-seize."
"Autolite -We do not recommend the use of any anti seize products for installing spark plugs. Anti seize compounds have a torque multiplying effect when installing plugs. This can lead to thread distortion and thread galling resulting in cylinder head damage. Autolite spark plugs are nickel plated to resist the effects of corrosion and seizing.
Anti-seize on the threads of your spark plugs will slow down the rate of heat transfer from the plug to the head. The worst place to use it is on the tapered seat, which is where the most heat transfer occurs between the spark plug and the cylinder head. Even just a small amount of anti-seize is the equivalent of using a hotter heat range spark plug."
"AC Delco - Do not use any type of anti-seize compound on spark plug threads. This will decrease the amount of friction between the threads. The result of the lowered friction is that when the spark plug is torqued to the proper specification, the spark plug is turned too far into the cylinder head. This increases the likelihood of pulling or stripping the threads in the cylinder head. Over-tightening of a spark plug can cause stretching of the spark plug shell and could allow blowby to pass through the gasket seal between the shell and insulator. Over-tightening also results in extremely difficult removal."
Last edited by WHT; Aug 9, 2009 at 10:08 AM.
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
I agree totally... just went through that myself. Noise gets induced into the systems by NGK's for sure and causes charge system fault issues. It was hard for me to believe it, but it was true.
Team Owner
Joined: Nov 2006
Posts: 21,136
Likes: 212
From: Long Island New York
First time I heard that. Without ant-seize how do you keep the plugs from fusing with the head? I have always heard that you need anti-seize especially with dis similar metals like steel and aluminum. Was that information incorrect? I could have sworn that the service manual for my 2002 Z28 LS1 said to put anti-seize on the plug threads before installing. I guess GM found that caused an issue later? Thanks for the updated information.
Read that other post and dont think that applies to Spark Plugs. Never heard the word "fastener" in relation to plugs.
Whenever to have disimilar metals in contact with each other, the less noble metal will be sacraficial and corrode. Many times I have seen aluminum head threads come out with plugs. USE ANTI SEIZE
Intermediate
Joined: Nov 2003
Posts: 48
Likes: 0
From: Arcadia CA
There I went and wasted my money again!
Like a dummy I went and bought the shop manuals shortly after buying my new C6 Z as I have done for the 7 perviously owned Vettes.
I like to read and/or review procedures that I do to my toys so that they will last and perform for a long long time.
I like to read and/or review procedures that I do to my toys so that they will last and perform for a long long time.