5.7 Hemi spark plug question

[Ronsant]

For any Chrysler/Dodge mechanics- I just changed the plugs on my 2006 Magnum. It was running rough when under acceleration, and I found a code for a misfire in cylinder #4, but no check engine light had come on.
These 2 plugs are from the same cylinder, and both are damaged and oily.
(Aside, Dodge dealer used iridium plugs instead of recommended copper plugs)
What would cause that type of damage to those plugs ?

Am I looking at replacing a spark plug tube seal, or more serious than that?

Thanks

 

[AandPDan]

Can't tell but is the electrode complete on both of the plugs?
Foreign object ingested? How is the air filter.

 

[f355spider]

I would suspect an ignition issue on that cylinder (coil). If that prong came off (or did it erode away?), that can cause damage to the intake or exhaust valves. Hopefully it exited the cylinder without causing damage to the valve seat or valve...and is probably lodged in the catalytic convertor...but that shouldn't be a big deal.

Might want to do a compression and leakdown test.

 

[Ronsant]

Can't tell but is the electrode complete on both of the plugs?
Foreign object ingested? How is the air filter.

Ground electrode is gone on one, and center electrode is gone on both.
Air filter is clean and relatively new.

 

[Rand]

at this point besides using a borescope on it.. put in fresh plugs and see what happens?

 

[Ronsant]

I would suspect an ignition issue on that cylinder (coil). If that prong came off (or did it erode away?), that can cause damage to the intake or exhaust valves. Hopefully it exited the cylinder without causing damage to the valve seat or valve...and is probably lodged in the catalytic convertor...but that shouldn't be a big deal.

Might want to do a compression and leakdown test.

Yes, I assumed that the ground electrode got spit out the exhaust valve.

 

[Ronsant]

at this point besides using a borescope on it.. put in fresh plugs and see what happens?

I installed the new plugs today and went for a short ride. Seems OK. I clears the misfire code and will take it for a longer ride tomorrow where I can warm it up and get on it a bit.
I don’t recall ever seeing a plug with the center electrode missing.
The plug tubes on that cylinder were very oily as well.

 

[slacktide_bitog]

Maybe a spark plug tube seal leak, valve cover gasket, possible coil problem

If those plugs were installed at the dealer, they're less likely to be counterfeit, I hope

 

[Ronsant]

Maybe a spark plug tube seal leak, valve cover gasket, possible coil problem

If those plugs were installed at the dealer, they're less likely to be counterfeit, I hope

Dealer did them about 40k miles go. Weird that they installed iridium. I went with NGK standard plugs and will plan on 30K replacement.

I’ll need to read up on the plug tube seals. Hopefully not too difficult.

 

[clinebarger]

The seals are just figure 8 looking gaskets that fit into the Valve Cover.

 

[Ronsant]

The seals are just figure 8 looking gaskets that fit into the Valve Cover.

Ordered Fel-Pro kit from rock auto. Looks like the passenger side is gonna be a poopshow to r&r

 

[OVERKILL]

I suppose it's possible that sufficient oil was making its way into that cylinder to cause detonation, thus damaging both those plugs, but I'd be looking to run a borescope on that cylinder, because the metal had to go somewhere and that doesn't look good.

Regarding why the dealership used Iridium plugs? I'm assuming because the later HEMI's spec'd precious metal tipped plugs and this recommendation has likely been back-spec'd to the older HEMI's.

 

[Ronsant]

Got the valve cover gaskets changed. Pass side is a huge PIA. Can’t come in straight with the cover, too much crap in the way.
First attempt had a leak where I couldn’t even see it. Bottom rear corner. Must have hit the gasket on a rocker arm while trying to get it on. Not wanting to ever do this again.
Plugs and coil are clean.