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Unread 04-18-2010, 06:36 PM   #1
I8AHUMR
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Hemi spark plug change write-up

Just changed the plugs on my Hemi and thought some might find a write-up useful?

First thing is the tools (see first picture)
1) 3/8" drive (could be 1/4" or 1/2" with the right adapter)
2) Spark plug socket
3) 10mm socket
4) 10mm wrench
5) 2 3" extensions
6) 1 6" extension
7) Spark plug gap
8) Angle adapter
9) Compressed air
10) Torque wrench
11) Dielectric grease
12) Anti-seize

Note the second picture where it shows the connector disconnected from the ignition coil. My setup is different from that found on wkjeeps.com. I have 8 'banks' of 2 plugs. In each bank one plug is underneath the coil and the other is right next to it with a normal plug boot. wkjeeps.com shows both plugs under the coil.

The first thing to do is notice that there's a small tab, pointed to in green, that needs to be pushed up towards the center of the engine. You really can't see it too well but it's in the green part of that connector. As this is pushed up you can use a flat head screwdriver to pull back the tab pointed to in red. After this push down on the connector with your thumb, pointed to in blue, and pull the connector towards the center of the engine.

After this remove the two screws pointed to by the yellow arrows. These are 10mm and are self retaining so you don't need to worry about backing them out all the way and dropping them somewhere where they don't belong.

Next just pull the coil out to expose the plug. Now you'll be able to get the plug socket into the hole so you can remove it. Before you do this and remove the plug blow some compressed air into the hole. On many of these you will be able to look and see if there's any junk in the hole. After blowing some air down there you can remove the plug. See the third and fourth pic.

Now you can remove the plug wire just to the back of that front plug hole. This boot comes out by simply pulling and twisting. Don't pull on the wire itself but rather the point at which it enters the hole. Now you'll be able to blow air in this hole and remove this plug. You should actually remove this boot before removing either of the two plugs. You don't want to remove the first plug and then remove this boot and have some junk fall back into the first hole and then into the head.

Now that you have the plugs removed from a bank take 2 new spark plugs (Champion 570 or equivalent) and gap them to 0.045. I've heard nothing but bad things about anything OTHER than copper plugs!!!! Research it yourself if you don't believe me. Anyway, I decided to put some anti-seize on the threads of the plug. Nothing excessive, just lightly fill the threads of the thread shank. After this I put a bit of dielectric grease on the ceramic part of the plug.

Now install the plugs and torque them to 12 in-lbs. Thread the plugs as far as you can with your fingers as you don't want to go crazy with the wrench and cross-thread them. You should be able to thread them by hand almost all the way. I really only needed to do at most a 1/4 turn with the wrench. Now just reinstall the plug wire/boot and the ignition coil the reverse way that you removed them. I put a bit more dielectric grease on the inside of the boots before reinstalling them.

Repeat for the other 7 banks (pairs). I found that the hardest bank to work with was the front drivers side. This is where the 10mm box wrench and the angle adapter came into play. The rest were easily accessible with various combinations of the 2 3" extensions and the 1 6" extension.

Hope this is useful to someone. Good luck!

Forgot to mention to remove the oil fill cap, remove the shroud, and put the oil fill cap back on first.

Last comment, if you're like me you'll start the motor and run it for a minute or two after doing each bank. If you get a OBD engine light you probably forgot to put the connector back on. ( I know from experience ) Don't panic, just put it back on, with the motor OFF, and recycle the motor a few times. That or you can just remove the negative terminal of the battery and reset it.

1.jpg   2.jpg   3.jpg   4.jpg  
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Last edited by I8AHUMR; 04-18-2010 at 06:47 PM..
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Unread 04-18-2010, 08:12 PM   #2
Texas WJ
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Nice write up.
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Unread 04-18-2010, 09:12 PM   #3
90grandoneer
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Installation Tips
Here are a couple of tips to help assure the success of changing spark plugs. The first is to remove spark plugs from aluminum cylinder heads only when the engine is cool. Since aluminum and steel expand and contract at different rates, removing spark plugs from an aluminum cylinder head while hot can actually cause thread and cylinder head damage. Before installing the spark plugs, make sure the threads are clean and in good condition. If in doubt, run a thread chaser through the plug opening in the cylinder head. 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.
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Unread 04-19-2010, 12:11 PM   #4
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Thank you very much for posting this. I'll be doing this in the next few weeks.
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Unread 04-19-2010, 12:20 PM   #5
Texas WJ
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I added this to the FAQ.
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Unread 04-19-2010, 05:29 PM   #6
90grandoneer
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I8ahumr, your write-up is very good, except as I indicated above. That paragraph is from the following: Champion - A Complete Guide To Spark Plug Performance
As far as I know, all spark plug manufacturers put anti-seize on the threads of new plugs. Now, if you take a plug out and reinstall again, then I would definitely use a small dab of anti-seize. Some of the other DCX forums have had this very discussion (heated at times). We went round and round and it is a very touchy subject with some folks, especially the ones that say it must be used on new plugs. The anti-seize acts as a thread lubricant and it becomes very easy to overtorque the plug (especially critical in an aluminum head), and risk stripping it out on the next removal. When using anti-seize on a reinstall, you should reduce the torque setting a couple in./ft. lbs. Also, on aluminum heads I personally would never change the plugs without using a torque wrench. Nowhere in the shop manual does it say to use anti-seize on a plug change. Also, you won't see any on the plugs you take out if they're the factory installed plugs. Hope this helps clarify this important issue.
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Unread 04-19-2010, 05:46 PM   #7
I8AHUMR
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Point taken... I've just always used a small amount. I only put anti-seize on the first third of the shank. On top of that I was very conservative with the amount. I'm sure it's been debated and everyone has their own opinion. I encourage everyone to research it for themselves and then do what they think is best. I also only mentioned torquing to 12 in-lbs. The spec is 12-14 with a max of 15 according to wkjeeps so if the anti-seize did affect it I doubt there's a major issue there.

It sounds like the debate on whether or not to use a friction modifier with a limited-slip differential when the gear oil manufacturer claims it's not needed. For example, I use Mobil 1 synthetic and they claim 'enough' is added to prevent chatter although I have still gotten chatter from my limited-slip without the modifier. As a result, I still add 4-5% by volume.

Anyway, I'm not debating this, just saying it's good information for anyone consulting the write-up...
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Unread 04-19-2010, 06:15 PM   #8
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Yep, the friction modifier debate is the same kind of deal as the anti-seize. I too don't think what you've done will cause you a problem, but some folks say to put a "liberal" amount on. I would vigerously oppose that. I also think by you staying at the lower end of the torque spec. is a good idea, especially when using the anti-seize. I am going to change my diff./Xfer case fluids soon, and will add the friction modifier to the Mobil 1. In this case I don't believe the additional will cause any addverse effects......I hope, LOL!
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Unread 09-09-2010, 01:05 PM   #9
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I8AHUMR -- Thank you for the GREAT writeup.

I have a 2006 Grand Cherokee with a Hemi. Are there any tricks I should know for removing the engine shroud? Do I just remove the oil filler cap and yank, or are there screws/bolts holding it on?

I just changed spark plugs on my 4.7 L Dodge Dakota. All of the controversies here (anti-seize, copper vs platinum, torque, etc.) are also running on the Dakota boards. I just used the original equipment copper plugs, added a tiny bit of anti-seize and dielectric grease, and tightened them a quarter turn after they were finger-tight. It worked FINE. This is car maintenance, not brain surgery.
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Unread 09-09-2010, 02:59 PM   #10
I8AHUMR
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Glad it's helpful for you...

The shroud isn't held on by any bolts/screws. Just remove the filler cap and pop it off. I'd show a bit of restraint b/c you need to shimmy it around the support bar. It should just pop off though. It's trivial
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Unread 09-09-2010, 03:02 PM   #11
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The shroud is only held on by the oil filler cap and 4 plastic post and rubber ball socket connections. Basically just pull it straight up. The strut tower brace makes this a tad more frustrating than it really should be.

You can see one of these suckers pretty clearly in the second photo. It's just to the right of the red arrow.
In the last photo you can see both of them per side as well.
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Unread 09-09-2010, 03:56 PM   #12
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Nice writeup ! IM doing it next week !
Can you tell us which brand/spec of the torquewrench you used please ?
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Unread 09-09-2010, 05:04 PM   #13
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I have a 3/8 in. drive Snap-On, but any good one will do.
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Unread 09-09-2010, 05:05 PM   #14
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I have no idea which brand I used. I have 5+ torque wrenches laying around and I don't know off the top of my head what the brand is of the one in the picture. The torque setting is 12-14 IN/LBS not FT/LBS. For torque settings that small it's going to be a 1/4" socket. You could pick up a cheap one anywhere I'm sure.

But of course you could use a 3/8" as noted in #13 if it goes that low (12-14 IN/LBS). No biggie...
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Unread 09-09-2010, 05:40 PM   #15
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Quote:
Originally Posted by I8AHUMR View Post
I have no idea which brand I used. I have 5+ torque wrenches laying around and I don't know off the top of my head what the brand is of the one in the picture. The torque setting is 12-14 IN/LBS not FT/LBS. For torque settings that small it's going to be a 1/4" socket. You could pick up a cheap one anywhere I'm sure.

But of course you could use a 3/8" as noted in #13 if it goes that low (12-14 IN/LBS). No biggie...
On WKJeeps, they say 12-14 Ft.lbs ! My torque wrench don't go under 20 Ft.lbs... also, the torque is critical... they say to dont go over 15 Ft.lbs. Cheap torque wrench and/or bad calivrated ones can go over 15 Ft.lbs even if they are set at 13... Beside using a torque wrench, it look like we can finger tigthening them and after, make 1/10th turn... What if my finger are too strong ? and if I make 1/8th trun ??
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