changing plugs in a Jeep w/waste spark

[Donald]

I am looking to change the plugs in my Jeep. Never did it before as the engine got replaced first.

It looks like I can just remove 6 bolts on the cover (has 3 humps) over where I assume the plugs are? Is that about it? I have plugs and new boots.

Less than one hour?

 

[Nick1994]

Apparently the newer 4.0L's are different than the older ones? I've changed plugs several times on a 91' and 96' 4.0L, all in the open and easy to do.

 

[bubbatime]

Originally Posted By: Donald
I have plugs and new boots.


New boots? What is that? I've heard of replacing the spark plug wires but not boots???

 

[bubbatime]

Should be SUPER simple on that straight six. The plugs are pretty easy to get to. Just remove any plastic covers or shrouds if there are any.

Jeep 4.0

 

[Donald]

Originally Posted By: bubbatime
Originally Posted By: Donald
I have plugs and new boots.


New boots? What is that? I've heard of replacing the spark plug wires but not boots???


The Jeep 4.0 for this year, has no wires. Plugs, and a boot with spring. All under a cover.

 

[Donald]

Originally Posted By: bubbatime
Should be SUPER simple on that straight six. The plugs are pretty easy to get to. Just remove any plastic covers or shrouds if there are any.

Jeep 4.0

Things have changed greatly with respect to the ignition on a 2001.

 

[Chris142]

13mm socket,extension and ratchet to remove the coil rail.pull up on it and let it flop out of the way. No need to unplug its harnes.5/8 plug socket to remove the plugs.

No Bosch platinums and no single platinum plugs as that waste spark system is very picky. I prefer autolite app985 gapped @.035.

Put dialectic grease on the boots and put the coil rail back on making sure that the boots go over the plugs.

13 mm socket,extension and ratchet puts the coils back on.

20 minutes tops!

 

[zrxkawboy]

Yep, starting in very late-1999, the 4.0 got a coil pack/rail. Chris142 is right on, except that I prefer standard copper plugs (either Champion or NGK) in the 4.0.

 

[SwampSurvivor]

Cheapo coppers work the best. I have ngk platinum in my 2000 currently because I couldn't find any copper plugs for it.

Be careful to not break the coil rail when removing it. Unbolt the bolts, the pull carefully. Also, when replacing the boots be careful to not lose any of the springs; they will fall out when you remove the boot.

When putting it back on, make sure the boots are all seated before bolting it back in

 

[Donald]

Originally Posted By: Miller88
Cheapo coppers work the best. I have ngk platinum in my 2000 currently because I couldn't find any copper plugs for it.

Be careful to not break the coil rail when removing it. Unbolt the bolts, the pull carefully. Also, when replacing the boots be careful to not lose any of the springs; they will fall out when you remove the boot.

When putting it back on, make sure the boots are all seated before bolting it back in


The new boots come with springs.

 

[Donald]

I have some NGK ZFR5N which I think are just copper.

 

[SwampSurvivor]

Should work fine.

 

[Donald]

Originally Posted By: Miller88
Cheapo coppers work the best. I have ngk platinum in my 2000 currently because I couldn't find any copper plugs for it.

Be careful to not break the coil rail when removing it. Unbolt the bolts, the pull carefully. Also, when replacing the boots be careful to not lose any of the springs; they will fall out when you remove the boot.

When putting it back on, make sure the boots are all seated before bolting it back in


I assume that when assembling it the boots w/springs go on each plug. The coil rack must have a contact prong that goes into each boot and touches the spring. The spring carries the spark to the plug.

What torque for the plugs? 20 ft/lb. Its not in the Haynes manual.

 

[artificialist]

Originally Posted By: Donald


What torque for the plugs? 20 ft/lb. Its not in the Haynes manual.

Sometimes the spark plugs will have a torque spec on the package. Do you still have the packages for those spark plugs?

 

[jeepman3071]

Originally Posted By: Donald
I have some NGK ZFR5N which I think are just copper.


Those are the recommended plugs for the 1999-2006 4.0s.

 

[Mitch]

NGK was the OEM plug for 2003. The ZFR5N is the plug I always use. I change mine at 25K,the factory recommends at 30K. There are 3 bolts holding the coil rail on. While you have the coil rail off check the heater hose for wear because the coil rail rubs on it. I put a piece of rubber sleeve on mine to protect it, seems like there was a TSB for that some years ago

 

[Donald]

Originally Posted By: artificialist
Originally Posted By: Donald


What torque for the plugs? 20 ft/lb. Its not in the Haynes manual.

Sometimes the spark plugs will have a torque spec on the package. Do you still have the packages for those spark plugs?


I have the box, it has 2 little spark plug icons, one says 1/16 and the other 1/2-2/3. No wording or torque. I believe its saying with crush washer (which mine has) its 1/2-2/3. I just love little uncommon icons with no words.

 

[Chris142]

The taper seat plugs only get about 1/8 turn .the washer plugs get about 2/3 turn.

 

[artificialist]

Originally Posted By: Donald
Originally Posted By: artificialist
Originally Posted By: Donald


What torque for the plugs? 20 ft/lb. Its not in the Haynes manual.

Sometimes the spark plugs will have a torque spec on the package. Do you still have the packages for those spark plugs?


I have the box, it has 2 little spark plug icons, one says 1/16 and the other 1/2-2/3. No wording or torque. I believe its saying with crush washer (which mine has) its 1/2-2/3. I just love little uncommon icons with no words.


Sometimes it means they want you to finger tighten the spark plug, then get a wrench and turn the spark plug a certain number of degrees.

On most iron heads, you can torque the spark plug until it feels right, and you will not have any problems.

 

[jeepman3071]

Originally Posted By: artificialist

On most iron heads, you can torque the spark plug until it feels right, and you will not have any problems.


This.

The torque spec for the plugs is 26-30 ft-lbs. I torqued them the first couple times on my Jeep, but it was kind of a pain to get to the last one with the torque wrench so I have just been tightening them by feel since then and they have been fine.