6.4 Plug Change Tips???

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FlatbedHemi

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Looking to see if there are any tips or tricks to changing the plugs out on a 6.4 Hemi. Pretty used to working on old Chevys, and I know Fords have some tricks to getting the plugs out. Just wondering if there's anything to the Hemi, like change them hot/cold, need a certain tool, remove this part or that?

Also, is there anything else that needs to be replaced besides the plug itself?
 

buckeyexx

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Yeah get an engine bay creeper so you can lay across that while getting rear plugs. Lol. Be really when I did mine I didnt have to have anything special other than a couple of extensions and swivel. I think it maybe took about 2-3 hours and that was taking my time
 

Zoe Saldana

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search youtube some good vids there.
Looking to see if there are any tips or tricks to changing the plugs out on a 6.4 Hemi. Pretty used to working on old Chevys, and I know Fords have some tricks to getting the plugs out. Just wondering if there's anything to the Hemi, like change them hot/cold, need a certain tool, remove this part or that?

Also, is there anything else that needs to be replaced besides the plug itself?
 

HEMIMANN

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Yeah get an engine bay creeper so you can lay across that while getting rear plugs. Lol. Be really when I did mine I didnt have to have anything special other than a couple of extensions and swivel. I think it maybe took about 2-3 hours and that was taking my time

Members report going through wheel wells eliminates overhead engine floundering?
 

buckeyexx

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I have seen reports of that. Could be easier access I suppose. I’ve never tried that method or looked at the possibility of getting to them from there myself.
 
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FlatbedHemi

FlatbedHemi

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But as far as changing them on a cold engine, there's no issues? My main concern is getting them out without breaking them. I know on a lot of Fords, you have to change them hot. My Chevy's were never a problem cold, but I've never change plugs on a Hemi before, so I'm not sure of the intricacies associated with. Id rather not work on a hot engine, but I don't want to snap them off either.
 

StickyLifter

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Always change with engine cold and always use a dab (just a dab will do) of antiseize on the threads with aluminum heads.
 

EdGs

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Check the plug mfg - some do not need/recommend that.

What people need to know is how to apply dialectic grease properly.
I believe the NGK site recommends not using antiseize as the threads are already coated.

As far as dielectric grease goes, the guy at NAPA told me he did a hemi and used the good part of a tube.

He must've slathered the entire boot with it, AND filled the plug wells too,......lol.

I simply ran a small bead with my finger around the plug near the base of the insulator, and put a dab on the end of the boot.

I wiped more dielectric grease off my finger than I used on the plugs. A little goes a long way. I have enough left over to last a couple lifetimes, and then some.
 

Wild one

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I believe the NGK site recommends not using antiseize as the threads are already coated.

As far as dielectric grease goes, the guy at NAPA told me he did a hemi and used the good part of a tube.

He must've slathered the entire boot with it, AND filled the plug wells too,......lol.

I simply ran a small bead with my finger around the plug near the base of the insulator, and put a dab on the end of the boot.

I wiped more dielectric grease off my finger than I used on the plugs. A little goes a long way. I have enough left over to last a couple lifetimes, and then some.
If you're using Dielectric grease,just put it on the plugs porcelin,not in the boot.Dielectric grease is an electrical insulator,so you only want it on the plug ,not the boot,so it doesn't slide up to the coil and plug connection
 

EdGs

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If you're using Dielectric grease,just put it on the plugs porcelin,not in the boot.Dielectric grease is an electrical insulator,so you only want it on the plug ,not the boot,so it doesn't slide up to the coil and plug connection
Oh yeah definately not in the boot, my dab is just like wiping the end of the boot off with the finger, should have been a little clearer about that.

Definately don't want to get it on the plug connections.

Still flips me out about how much the NAPA guy said he used, I don't even see how that's possible.
 

2020PW

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If you use anti seize on the threads of the plug it changes the torque spec and you can damage the heads. I believe that lubing the threads will decrease the torque value 20%.

Most spark plug have a dry film lube on the threads from the factory.
 

HEMIMANN

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If you use anti seize on the threads of the plug it changes the torque spec and you can damage the heads. I believe that lubing the threads will decrease the torque value 20%.

Most spark plug have a dry film lube on the threads from the factory.

Correct - general coefficient of friction for dry threads is 0.15, for lubed threads it's 0.20. That's 1/3 more applied torque to get the same bolt stretch (tightness).
 

Bigskyroadglide

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When it's time to apply antiseize, I stop and look at it for. 5 seconds then install the plug. NGK specifically says, "no antiseize "

So far it's working
 

Zoe Saldana

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I believe the NGK site recommends not using antiseize as the threads are already coated.

As far as dielectric grease goes, the guy at NAPA told me he did a hemi and used the good part of a tube.

He must've slathered the entire boot with it, AND filled the plug wells too,......lol.

I simply ran a small bead with my finger around the plug near the base of the insulator, and put a dab on the end of the boot.

I wiped more dielectric grease off my finger than I used on the plugs. A little goes a long way. I have enough left over to last a couple lifetimes, and then some.

That's about it. People should not put it on metal parts - it inhibits electricity flow/connection.
 

buckeyexx

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When it's time to apply antiseize, I stop and look at it for. 5 seconds then install the plug. NGK specifically says, "no antiseize "

So far it's working
Same here. Have never used it
 
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I have never changed plugs on a hemi and I dread the day I have to do it.
However, I read several articles to go through the fender well on some of the back plugs.
Youtube might give you some ideas too.
Keep us posted on it. Good luck.
 

Neil Derryberry

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+1 to no antisieze.

The back two plugs on the driver's side are not too bad to get from up top if you go under the brake reservoir. You'll see what I mean when you get in there.. not quite sure how to put it other than that.

I had enough room in the wire harness to skip the step of disconnecting the coils from the wire harness. Those locks are a PITA..

Just bring your patience. It wasn't the easiest change I've ever attempted but I got through it ok, you will too.
 
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FlatbedHemi

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Changed em out. All went pretty smoothly considering. Plugs looked well used compared to the new ones. On the rear plugs I was noticing that the threads looked damp and smelled like oil and gas (third picture), but the fronts were dry. The electrode was dry. The fluid appeared to only be on the threads. Never noticed this before when changing Chevrolet plugs. Is this normal for a Hemi, or a sign of a problem?
 

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