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I'm thinking about doing the spark plug swap as my next project. I've looked up gaping and am under the impressions .033 mil is the best bet for performance, however I'm curious its interference with my turbo and the computer tuning, or if it will affect at all and I also need the part number to order at advanced or auto zone if anyone has that information handy, like I said I have a turbo and am open minded to the copper being a better conductor so send me your thoughts as well ! Thanks all !


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The gap should be 0.028 inches. Spark blowout occurs when the gap is so big that the air flow through the cylinder extinguishes the spark before the fuel can be injected in to the cylinder.
 

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How often are you guys needing to swap out those copper plugs? I went with ACdelco 41-121 so I can easily go another 75,000 miles before I even look at them, that way I can probably trade the car before I need to do that maintenance again.
 

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How often are you guys needing to swap out those copper plugs? I went with ACdelco 41-121 so I can easily go another 75,000 miles before I even look at them, that way I can probably trade the car before I need to do that maintenance again.
Not sure, I been through 2 sets of them before going EIX iridium's. I waited to the "V" was gone to toss them.
 

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Like spaced I haven't had any problems with the Delcos either. Matter of fact, my tuned car runs best on them. Bc I am tuned, I am gapped at .030 with no problems.
 

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Maybe I am too critical, can notice a slight difference in performance even after 15K miles of driving, just cleaned my plugs yesterday. Slightest amount of carbon build up on that center electrode insulation shunts a portion of that spark back to ground.

Heard a rumor there is carbon in our fuels. Anti-seize is a must, a steel plug in an aluminum head causes electrolysis that bonds these two dissimilar metals together. Leaving them in for a long time, the treads in the head come out with the spark plug.

Been dealing with copper spark plugs, far longer than most of you kids that weren't even thought of, melting point of copper is low, electrodes get rounded, ground electrode has a gap worn in it. Some vehicles were an absolute PITA to replace the plugs, like removing the entire upper intake manifold, an AC compressor or a PS or alternator to reach them. The Cruze is an absolute pleasure.

To me, double platinum is a blessing from heaven, checked my plugs under my stereo microscope, edges were still sharp even after 40K miles, use ground walnut shells in my blaster to clean them, does not remove the plating, just the carbon. Difference between a sharp edge and a rounded edge is huge in electrostatics.

Here is another reason to keep your plugs in top condition, the catalytic converter, one even slight misfire puts excess oxygen into the O2 sensor and it thinks the engine is running lean, so it increases the dwell to ALL the injectors putting raw gas into this cat that over heats it and burns it up.

Even a partially restricted cat causes a chain reaction and we knew this back in the 70's so insisted on using an O2 sensor for each cylinder, the bean counters won out. Gap mine at 25 mils, and keep them clean, saves a lot of long term grief.
 

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I checked the gaps on all my plugs which where never checked before 83,000 miles, 3 were exactly 0.28 and one was 0.26. I see no need to check them let alone replace them as often as some on here are. On the same note, my coil pack came off with ease as well as the plugs, neither had any anti-seize or dielectric grease previously.

If you put anti-seize on your plug would it not be the same thing as lubing your lug nuts when it comes time to torque them down? Seems this would throw off any reading and probably cause them to be over tightened.
 

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Like spaced I haven't had any problems with the Delcos either. Matter of fact, my tuned car runs best on them. Bc I am tuned, I am gapped at .030 with no problems.
You must not drive that aggressive or stay in eco. .030 is P0300 for me all day if I even so much climb a hill.

Stock plugs are "doable when gapped right" but the Coppers and EIX iridiums are great. I puled mine yesterday and they need to be replaced soon. Gaps were still .028 and they been in for about 20K miles and a coil pack failure with 1 cylinder not even firing.

I also agree cleaning the plug the best I could helped. I also tossed seafoam down the holes and let it sit for 10 mins at normal tems. I cleaned the holes before of debris, looking down with a flash light the pistons look almost clean at 55K. Wish I could take pics of them.

I also didn't use anti seize, just MP on the springs and silicone on the rubbers.
 

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Torque specifications are based on clean lubricated threads, been this way since the beginning of time. With this darn road salt, if I don't put on a thin coat of anti-seize on my lug studs, will break them off trying to remove the lug nut.

With aluminum heads, a necessity to embed steel inserts for the valves, if they don't, particularly in the exhaust valve, a head would only last about ten minutes. Some even go as far as using steel inserts for the plugs, have to admit ignorance on exactly what the Cruze is doing, kind of a very deep hole even to look at them.

Not talking about using a gallon of this stuff, just a very thin coating, but had some very bad experiences with this when they started using aluminum heads, this dates back to the early 70's. Particularly on small engines. That 98 Ford ZX2 sure gave me grief, so don't want to risk it.

KD tools makes a kit using a steel spark plug insert with a high temperature epoxy to hold it in. Had to do this with my Onan generator, but to do it right, had to remove the heads, two cylinder engine valve in block that was fairly easy. Not an easy job on any overhead cam engine, so prefer preventative measures. All that timing chain stuff has to be removed.

Also coat the insides of the boots with dielectric grease, if you don't do this, they will bake on. Like a Chinese finger puzzle, the harder you pull, the tighter they get. While I do have a right angle tool with a U cut into it, can slip that on the side of the plug and pull the boot off while compressing it. But can't do this in a blind hole.

Then those springs inside of the boots, the tips can get hung up on the shoulder on the inside. So had to stretch them out so this won't happen. At an angle, can see if I am getting good contact with the plug terminals, say a pray and push it down and hold it until those two screws are firm.
 

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Torque specifications are based on clean lubricated threads, been this way since the beginning of time. With this darn road salt, if I don't put on a thin coat of anti-seize on my lug studs, will break them off trying to remove the lug nut.
The lug studs are supposed to be clean and dry.

Installing lube alters the fasteners stretch vs torque curve which results in overstretching of the lug-stud to achieve the specified torque. You could snap off the lug due to over stretch because of the lubrication.

 

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The lug studs are supposed to be clean and dry.

Installing lube alters the fasteners stretch vs torque curve which results in overstretching of the lug-stud to achieve the specified torque. You could snap off the lug due to over stretch because of the lubrication.

In addition to doing the same with spark plugs, it alters the heat range and heat dissipation of spark plugs as well.

The coppers lasted about 20k for me before they're worn out and performance goes downhill. 2-3 regaps in that time - only 2 really necessary.

I too have gone for the iridium ones, mostly because I'm lazy. These iridium ones have a nickel rather than platinum ground strap though, so they will need more frequent regappjng than the IFR/ACD stock plugs, but should last nearly as long.
 

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Only way to keep your nuts and bolts clean and dry is to leave your vehicle in the showroom. Procedure for dealing with proper torquing dates back well over a hundred years, not sure where you are getting your information from.

Spark plugs use to be sold by heat ranges, hot for city driving cold for the highway, add this to the history books.

Could get more life out of copper by using a point file on both electrodes, but the ground electrode had to be perfectly reformed to be perpendicular to the axis of the plug, takes a bit of skill to do this. 10K miles was just about the limit, but so were the ignition points.

Iridium is a gift from aliens from outer space, not sure if a good or bad gift. Electrodes are so thin, very poor heat conductivity, I never had good success with these.

Double platinum, lots of mass, after cleaning still look good after 40K miles. But any plug will carbon up with carbon in the fuel and is conductive. But also depends on the kind of driving you do, will stay cleaner a lot longer with lots of highway driving. City driving is the worse possible scenario for carbon build up. So really no set rules on this subject.

Any of you guys design ignition coils? The size and type of material use in the core is the key factor in determining the energy in joules for each spark plug firing. In one sense, the larger the core, the more the energy, ever deal with bean counters? The smaller the core, the cheaper it can be manufactured.

For years, the only limited factor for the coil current was the resistance of the primary, this not only increased the power dissipation of the coil, but also increased the secondary losses. But we got around this by firing it with a controlled current device.

Since energy is fixed with the quantity of joules can either get high easy to blow out voltage and weak current with a larger gap. Or a much stronger spark with a smaller gap, the smaller the gap, the better. Key limitation is having that gap bridged by carbon, again, carbon is the problem. So larger gaps are typically recommended. Real cure is to use a larger coil, but then the bean counters come into play. Or just use a smaller gap and clean them more frequently. High performance engines use a very small gap in the neighborhood of 10-15 mils.

So just don't look at automotive, look everywhere where a spark plug is used. Kettering started all this in around 1910. Lots of technical data has been written since then.
 

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No 10. A standard spark plug socket, long extension, and socket wrench. I think the coil pack bolts are T25.

Make sure to get yourself a gap tool and have a set of needle nose pliers on hand. The spark plug feeler gauges are better than the cheap coin things.
 

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I have the quarter looking gaping tool, and the T25 where can I find the spark plug socket?
Would the Home Depot "husky" one work?

2011 Chevy Cruze LTZ 1.4L Turbo
5/8" spark plug socket - should be included in most sets. It's the one deep (long) socket that has a hex shape at one end to fit a wrench on. Otherwise available at the counter at any auto parts store for a couple of bucks. They're usually 3/8" drive.

You'll need a 6 inch socket wrench extension to reach down into the plug well.

The job literally takes 15 minutes, tops, to change all 4 plugs. Definitely isn't Ford mod motor on a 2000 Expedition or F150. You gotta take too much stuff off to get to the rear plugs and coils. I will never buy one of those if I can help it.
 

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Discussion Starter · #20 ·
Definitely isn't Ford mod motor on a 2000 Expedition or F150. You gotta take too much stuff off to get to the rear plugs and coils. I will never buy one of those if I can help it.
Was talking to some guys in my class and they were saying the same thing about their f150s lol, thanks though I'll pick all that up Saturday morn


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