What's up with plugs?
 

Checked my plugs yesterday and all of them looked real dirty but #4 is perfectly clean?? I changed intakes a few weeks ago and noticed there was a little oil on top of the closed valves. ( assuming I need new seals possibly guides). I also did compression test and all cylinders were within 5 psi of each other. Could this be rings? Blowed head gasket steam cleaning plug? There is no water loss though. Maybe the valve seals on that cylinder are good? Plugs are tr6 Thanks for any help
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That crazy clean compared to the other, doesn't even look used. I'm definetly interested to hear the answer.

How much oil is in the old intake? PCV system can put a lot of oil in the intake port without a catch can. How long have you had the (vehicle?)? Did you install these plugs yourself to know they are the same age? How old are they?

From those pics, both look to have oil on them; the top plug looks to have more carbon build-up.

Oil wasn't in the intake just some on intake valves ( likely seals or guides). Had the motor running for 2 years. I don't run a PVC just breathers. Plugs are about 2 months old. That is never sieze on the clean plug not oil

Well aside from the obvious then(and what you've stated), could it be fuel washing the plug?

I guess it's a possibility but with a Vic jr and a carb I don't see how it would be only one cylinder. I though maybe that cylinder wasn't firing but the engine runs amazing

When you say #4 are you referring to the second plug from the radiator on the passenger side? I grew up Ford so I was thinking maybe fuel puddling in the back of the intake between runs or similar. Remembering now LS is numbered cross-bank.

Yes second cylinder from front on passenger side

That's all I've got unless somehow the NO2 plate is washing that one off. But fuel probably wouldn't get it that clean anyway if all else was the same. Let's go the valve seal route--not unlikely--but it seems like the other plugs would look dirtier by comparison. Maybe just a combo of your camera and my monitor but the insulators on both of those plugs look surprisingly "white" for 2 month plugs with oil in the intake port. Then again, I have no idea how much/little you have driven/run in that time. I am also not terribly experience with NO2. I understand it all but I haven't run it so maybe something else about that dynamic we're missing.

Maybe stick a little camera in the hole and take a look at the tops of the pistons. I have heard of some real cheapie USB cameras that will fit in a spark plug hole and viewable through a laptop.

In haven't run the nitrous through it yet because I want to get this oil issue figured out first. Nitrous and oil don't mix well. I would say the plugs have maybe 100 miles on them. Just a weekend toy. I know it runs a little rich and that could be the cause of the soot on the plugs too but there is oil on the threads and the motor burns a little oil. Not a lot. I was just amazed when I pulled that one plug out and it was so clean? Maybe an excuse to get new heads

Well I consider a bad day at work an excuse to get new heads...so by all means if you have actual supporting physical evidence. :)

Cylinder 8, 6, & 4
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Drivers side bank
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Fire it up and see if that header pipe has heat. Checking with an infared gun against the other cylinders is easiest. One of my coils was going out. Mine however was fouling them due to weak spark. If yours is not firing at all it would be clean. Was hard to tell, but a very small miss at idle. However, eventually my o2 sensors ( I know you don't have them) started commanding a ton of fuel and causing the motor to break up.

Glad you said that my dad has a temp gun I will borrow from him tomorrow and try it.

Agreed. That's a great idea. Nice if the only problem is a dead coil. And if you thought it ran well before..1/8th more power should be outstanding.

Well it was the coil! Shot it with the temp gun and it was a couple hundred degrees colder. Swapped a coil off my daily driver Sierra and the temp came up with the others! I did notice a few bubbles in the radiator though. Compression is all within 5 psi of each other though. Haven't really noticed water loss and there doesn't seem to be any in the oil. Am I just paranoid with the bubbles?

If it was pushing water the overflow would be full. Or a plug would have crystals on it.