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Unread 03-22-2012, 05:14 PM   #1
modernblueWK
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2008+ 4.7 sparkplug swap how to

((((Update 8/2013 FYI: do NOT use the cheaper/shorter bosch plugs. Get the FR8TE2's as recommended.

They are referred to as SPFR8TE2AA_8

Here they are $36.72 for 8. just for jeeps))))

I decided to swap out my spark plugs today. I read in numerous places online that guys with 2008+ dodge rams and dakotas with the 4.7 have used the Bosch 7962 copper plug successfully in place of the FR8TE2 factory spec plug.
The FR8TE2 are $14 each at the closest jeep dealer to me. The Bosch 7962's are $1.19 each at my local napa. I also read that the coil boots can rip when you remove them since they seem to weld themselves to the porcelain on the plugs. I live 1.5 hours from a jeep or dodge dealer.

Tools:
1/4" ratchet
3/8" ratchet

3/8" long and short extension
1/4" long and short extension

5/8" thin wall spark plug socket
10mm socket

After you remove the air intake tubing and the airbox attached to the throttle body you will see this:


Coil pack:
1. Remove the electrical plug.
2. Remove the Secondary plug wire.
3. Remove the 10mm bolt that holds the coil pack down.


If you push down here with a screwdriver (lightly) and pull the plug it will slide off easliy.


I wiggled and pulled the first coil up slowly. It popped right off with no drama and in one piece!!! Mine had some yellow spark plug boot grease in the boots.


So add a bunch of new spark plug boot grease for the future.


Next you will need a thin wall 5/8" spark plug socket. I got lucky in that the 5/8" that I have is thin enough. It was thin enough for 6 of the 8 cylinder holes. I had to sand it down a bit to get it to fit #8 and #5.


Plugs removed:
Top is the factory FR8TE2
Bottom is Bosch 7962
The old plugs were about .046 gap where the new ones were all right on .040 as spec'd. Not in bad shape though for 51k miles.
Without knowing the combustion chamber profile of the second gen 4.7 we really do not know how shrouded the shorter spark plug is or how far the longer plug sticks into the chamber.


Coil Pack in one piece:


Tighten the new plugs to 20 ft lbs.

Reinstall in reverse. Plug #8 (furthest rear, passenger side) is a real pain though. Everything under the hood of this thing is sharp and black. so be prepared for some skinned knuckles.



I took the jeep out for a drive 20 miles east of town to make sure it was running ok with the new plugs. It felt like it was slightly down on power at first. I removed the negative batt cable in this process so maybe it needed to relearn some parameters. In my 40 mile shakedown I was getting 22-23 mpg average out there and back and all the normal power was there. It idles smoother now too.

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Unread 05-06-2012, 02:26 PM   #2
Mike94ZLT1
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Good write up, thank you! Does anyone have one for the lower plugs? They seem like a real pain.
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2009 Jeep Grand Cherokee Laredo 4.7, 4WD, Stock for now
2006 Ford E-150 4.6, RWD, "The Happy Bus"
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Unread 05-06-2012, 02:55 PM   #3
modernblueWK
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I am avoiding those until 100k miles.
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Unread 05-21-2012, 05:19 PM   #4
modernblueWK
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Update: no problems, runs great with the cheap plugs. Averaging 18+ mpg combined.

FALSE. Read my post below.
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Last edited by modernblueWK; 08-30-2013 at 10:15 PM.. Reason: Not correct
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Unread 05-21-2012, 07:04 PM   #5
Mike94ZLT1
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I just did this tonight, took me about an hour and a half. I spent about 6 hours finding a spark plug socket that would fit. Craftsman won't fit, neither will the ones carried by Advance Auto, Auto Zone, O'Reillys, Pep Boys, or Napa. The one I found that finally fit was at Home Depot. It was the "Husky" brand, and it came in a 3 pack with other plug sockets. The 5/8 Husky that was available by itself was different from the one in the 3 pack, and will not fit. So for those of you that want to tackle this, make sure you stop at Home Depot first.

The job was pretty easy, I did the front drivers first, just to make sure the socket would fit. Then I did the passenger rear, and worked my way forward. Not too bad, but after years of wrenching on LS1's, LS2's, LS3's and LS6's this was a walk in the park comparatively.

It did make a noticeable improvement in idle quality and throttle response, and it just seemed to run a bit smoother overall. Maybe it is in my head, but I would definitely say if you have 50K on your Jeep, do it.
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2009 Jeep Grand Cherokee Laredo 4.7, 4WD, Stock for now
2006 Ford E-150 4.6, RWD, "The Happy Bus"
1999 Corvette FRC 383 LS6 stroker, built drivetrain, full suspension, not much left that's stock
1937 Ford 5 Window Coupe 327 SBC, M-22 4 speed, etc..
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Unread 01-21-2013, 10:25 AM   #6
melibokus
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I was just about to do this but have a problem. The first time I did this I used the shorter reach Bosch 7962's. This time I got the FR8TE2 which is correct in the owners manual etc and has the much longer reach (as modernblueWK shows in his picture) than the 7962's. I am sure that the FR8TE2 I bought are not the right plugs for my '08 4.7 V8 FlexFuel but they could be easily be installed by mistake.

I installed one of the FR8TE2 and it does not fully seat in the socket. The top of the plug is visibly higher up than the 7962's and I could see that the top 3/10 inch of threads on the FR8TE2 was not touched (I put some anti-seize on the plug and tightened it down to see). I guess it would be safe to install the plugs because the cylinder head threads would prevent an over-long plug from being installed but the plug would not seat and is clearly too long for this engine.

Has anyone else seen this problem? Is there a special FR8TE2 with less threads than mine (I measure total threads on the FR8TE2 to be 9/10 inch)

BTW if someone is doing this for a second time. The per plug coil (the boots) came off really easy the second time around (the first time I had problems where the boots were melted to the plugs from factory after 30K miles).

Mark
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Unread 08-30-2013, 10:13 PM   #7
modernblueWK
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Update...

My mpg's have gone down to 15-16 mpg average. I noticed a slight miss around town and noticed a distinct lack of power on a recent trip over monarch pass.

I decided to buy a set of the proper plugs FR8TE2 from just for jeeps. They came in mopar boxes so I am sure they are the right ones. Spent an hour in the garage, swapped the short bosch plugs out for the mopar plugs.

What a difference!!! Power is back, mpg's are up and the engine runs alot smoother at part throttle around town.

So..... Buy the FR8TE2's they work better.

Here is the best deal i have found: http://www.justforjeeps.com/inspplfor08w.html
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